MDI Transportation Guidelines - Polyurethanes - American ...

ALLIANCE FOR THE 

POLYURETHANES 

INDUSTRY 

A BUSINESS UNIT OF THE AMERICAN PLASTICS COUNCIL 

MDI Transportation Guidelines

MDI transportation 

g u i d e l i n e s 

c o n t e n t s 

Chapter 1: Introduction .................................................................................................................1 

1.1 Purpose ........................................................................................................................1 

1.2 Safe Handling Precautions .............................................................................................1 

1.3 Transport and Distribution Regulations ...........................................................................1 

1.4 Scope ...........................................................................................................................1 

1.5 Exceptions ....................................................................................................................1 

1.6 Use of Guidelines..........................................................................................................1 

1.7 Transport Contracting Responsibility...............................................................................2 

1.8 Evaluation Application...................................................................................................2 

1.9 Interpretation Caveat ....................................................................................................2 

Chapter 2: Properties, Hazards and Safety Information for MDI.........................................................3 

2.1 Product Identification and Exposure Limits .....................................................................3 

2.2 Typical Physical Data .....................................................................................................3 

2.3 Reactivity Data .............................................................................................................3 

2.4 Health Effects—Short Term ............................................................................................4 

2.5 Health Effects—Long Term.............................................................................................4 

2.6 First Aid Procedures ......................................................................................................5 

2.7 Disposal .......................................................................................................................6 

2.8 Recommended Formulations for Decontaminant Solutions ................................................7 

Chapter 3: Safety Auditing of Tank Truck Carriers and Bulk Tank Operators ........................................9 

3.1 Carrier’s Capability: Assessment and Control ...................................................................9 

3.2 Carrier Safety Audits .....................................................................................................9 

3.3 Carrier Safety Audit Procedure .......................................................................................9 

3.4 Meeting Safety and Regulatory Standards........................................................................9 

3.5 Scope ...........................................................................................................................9 

Chapter 4: Design and Construction of Transportation Equipment and Packaging..............................11 

4.1 Rail Tank Cars (RTCs)...................................................................................................11 

4.2 Cargo Tanks (Tank Trucks) and Inter-modal Bulk Tank Containers (ISOTainers).................11 

4.3 Intermediate Bulk Containers (IBCs) ............................................................................12 

4.4 Drums.........................................................................................................................13 

Chapter 5: HazMat Training ..........................................................................................................15 

5.1 Training Requirements .................................................................................................15 

5.2 Specific Requirements for MDI .....................................................................................15 

5.3 Driver Criteria for Transporting MDI ..............................................................................15 

5.4 Certified Drivers..........................................................................................................15 

Chapter 6: Personal Protective Equipment for Loading or Unloading MDI .........................................17 

Chapter 7: Loading Operations .....................................................................................................19 

7.1 Compliance With Transport Regulations ........................................................................19 

7.2 Criteria for Loading Facilities and Transport Equipment .................................................19 

7.3 Design and Construction of Transport Equipment ...........................................................19 

7.4 Availability of Written Operating Instructions ...............................................................19 

Copyright 2001, American Plastics Council 

iii



c o n t e n t s 

7.5 Availability of Personal Protective Equipment................................................................19 

7.6 Inspection of the Bulk Transport Equipment..................................................................19 

7.7 Inspection List: Modifications ......................................................................................22 

7.8 Additional Inspections.................................................................................................22 

Chapter 8: Transport of MDI by Rail ..............................................................................................23 

8.1 Responsibilities of Rail Carrier.....................................................................................23 

8.2 Emergency Intervention ...............................................................................................23 

8.3 Inter-modal Movements ...............................................................................................23 

Chapter 9: Transport of MDI by Road.............................................................................................25 

9.1 Routing ......................................................................................................................25 

9.2 Safe Parking................................................................................................................25 

9.3 Severe Weather Conditions ...........................................................................................25 

9.4 Delays or Accidents .....................................................................................................25 

9.5 Inspections During Transport........................................................................................26 

Chapter 10: Transport of MDI by Water Vessel................................................................................27 

10.1 Approved Containers..................................................................................................27 

10.2 Parties Involved ........................................................................................................27 

10.3 Safety Audits ............................................................................................................27 

Chapter 11: Unloading Operations for Tank Trucks and Rail Tank Cars..............................................29 

11.1 Criteria for Discharge Facilities ..................................................................................29 

11.2 Design, Location and Checks ......................................................................................29 

11.3 Criteria for Discharge ................................................................................................29 

11.4 Operating Procedures.................................................................................................29 

11.5 Protective Equipment for Operators ............................................................................29 

11.6 Inspection of the Bulk Reception Facilities .................................................................29 

Chapter 12: Required Shipping Information for MDI.......................................................................31 

12.1 MDI’s Hazardous Materials Classification .....................................................................31 

12.2 Summary of MDI Hazard Information...........................................................................31 

12.3 Preparedness and Emergency Response .......................................................................32 

12.4 Principles of Emergency Response Scheme ..................................................................32 

12.5 Technical Communications..........................................................................................32 

a p p e n d i c e s 

Appendix 1: Sample Certificate of Receipt ...................................................................................1-1 

Appendix 2: Guidelines for the Unloading of Tank Trucks (A Suggested Checklist) ..........................2-1 

Appendix 3: Guidelines for the Unloading of Rail Cars (A Suggested Checklist) ..............................3-1 

Appendix 4: Guidelines for Customer Bulk Storage Facilities (A Suggested Checklist) .....................4-1 

iv Copyright 2001, American Plastics Council



Chapter 1: Introduction 

1.1 Purpose 

These Guidelines have been prepared by the Alliance for the Polyurethanes Industry (API). They are intended 

to summarize both regulatory requirements affecting the transport and distribution of Methylene Diphenyl 

Diisocyanate (MDI), and relevant industry safety recommendations. 

1.2 Safe Handling Precautions 

The U.S. Environmental Protection Agency (EPA) regulates pure MDI to the extent that a release involves 

an amount equal to or exceeding the 5,000-pound reportable quantity (RQ). The U.S. Department of 

Transportation (DOT) regulates the shipment of hazardous substances that are regulated by the EPA. EPA 

lists pure MDI as a hazardous substance, and DOT regulates the shipment of pure MDI when contained in 

single packages equal to or greater than the RQ of 5,000 pounds. Mixtures of MDI are regulated if the 

amount of pure MDI in the mixture equals or exceeds the RQ amount. (Polymeric MDI contains about 50% 

MDI; therefore a single package of 10,000 pounds would be subject to DOT regulation.) It is recommended 

that all federal, state, and local regulations are reviewed prior to the storage and handling of MDI. 

1.3 Transport and Distribution Regulations 

Except in packages containing less than 5,000 pounds, the transport of MDI within the United States is 

regulated by the DOT. In addition, export shipments may be regulated by various international organizations 

that establish specific transport requirements that must be observed by all parties. 

1.4 Scope 

These Guidelines take into account the transportation of MDI in bulk tank trucks, rail tank cars, intermediate 

bulk containers (IBCs), inter-modal portable tanks, and drums. They cover most aspects of transport from 

loading to delivery point. Recommendations are denoted by the use of the word “should”; regulatory 

requirements are indicated by use of the word “must.” 

1.5 Exceptions 

These Guidelines do not deal with bulk movement of MDI in ocean chemical tankers or inland waterway barges. 

1.6 Use of Guidelines 

It is API’s goal to promote the safe transportation and distribution of MDI. API encourages the use of these 

Guidelines as a means of facilitating this goal. 


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1.7 Transport Contracting Responsibility 

When offering MDI for distribution, companies should arrange transport with reputable, experienced carriers, 

to facilitate safe transport. 

1.8 Evaluation Application 

It is the individual responsibility of users of these Guidelines to evaluate and apply them, taking into account 

all specific circumstances of their own situation. 

1.9 Interpretation Caveat 

No part of these Guidelines may be interpreted in a manner that would conflict with existing international 

and/or national legislation. Standards may change, and legal provisions always have precedence over any 

part of these Guidelines. Consult with appropriate legal experts to verify applicable requirements. 

2 Copyright 2001, American Plastics Council



Chapter 2: Properties, Hazards and Safety Information for MDI 

2.1 Product Identification and Exposure Limits 

CAS No. OSHA PEL1 ACGIH TLV2 4,4’-Diphenylmethane diisocyanate (MDI) 101-68-8 0.02 ppm (ceiling) 0.005 ppm (8-hour TWA3 ) 

Polymeric MDI 9016-87-9 — — 

1 Permissible Exposure Limit 

2 Threshold Limit Value (TLV is a registered trademark of ACGIH) 

3 Time Weighted Average 

2.2 Typical Physical Data 

2.3 Reactivity Data 


4,4’ MDI PMDI 

Appearance solid, below 38º C liquid 

Boiling point 200ºC @ 5mm Hg 200ºC @ 5mm Hg 

Color white to yellowish brownish 

Decomposition point 230ºC 260-340ºC 

Density (pounds/gallon) 10.22 10.22 

Freezing/Melting point 38ºC varies 

Odor none slightly aromatic 

Solubility in water not soluble; reacts with the evolution of CO2 not soluble; reacts with the evolution of CO2 

Specific gravity 1.33 @ 20ºC (solid); 1.18 @ 50ºC (liquid) 1.24 @ 20ºC 

Vapor pressure 200ºC 

Auto-ignition Not available Not available 

Explosion limits Not available Not available 

Thermal degradation >200ºC >200ºC 

Hazardous degradation products CO, CO2, NOX, HCN CO, CO2, NOX, HCN 

Materials to avoid water, alcohols, amines, acids, bases water, alcohols, amines, acids, bases 

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2.4 Health Effects—Short Term 

Commercial MDI (polymeric MDI) contains a substantial proportion of monomeric MDI (typically 40 to 60%), 

so the health effects of pMDI are considered likely to be similar to pure MDI, unless there is a specific reason 

or determination that the health effect differs. Typically, there are four routes of potential exposure: inhalation, 

skin contact, eye contact and ingestion. 

Inhalation 

At normal unloading and storage temperatures, MDI has a relatively low vapor pressure. With adequate 

ventilation, airborne MDI vapor concentrations are unlikely to reach or exceed exposure guidelines. 

Nevertheless, at elevated temperature, or if MDI is aerosolized, the following health problems may result: 

• Inhalation of MDI may cause irritation of the mucous membranes of the nose, throat or trachea, 

breathlessness, chest discomfort, difficult breathing and reduced pulmonary function. It is important to 

avoid exposure above the TLV to minimize the possibility of respiratory sensitization. 

• Overexposure well above the PEL may result in eye irritation, headache, chemical bronchitis, asthma-like 

symptoms or pulmonary edema. Diisocyanates have also been reported to cause hypersensitivity 

pneumonitis, which is characterized by flu-like symptoms, the onset of which may be delayed. 

Skin Contact 

Skin contact may result in an irritant or allergic contact dermatitis and may play a role in respiratory sensitization. 

Skin staining or discoloration may occur. Long term contact may cause redness, swelling and blistering. 

Eye Contact 

Eye contact with MDI may result in conjunctival irritation and corneal opacity. 

Ingestion 

Ingestion is not a typical route of exposure unless contaminated food or tobacco products are inadvertently 

ingested. Good industrial hygiene practices do not allow eating of food or use of tobacco products during 

the transfer of MDI. If MDI is ingested, severe irritations of the mucous membrane of the mouth, esophagus 

and stomach may occur. 

2.5 Health Effects—Long Term 

Inhalation 

Control of MDI exposure to the recommended guidelines (0.005 ppm as Time Weighted Average, 0.020 ppm 

as Ceiling) is believed to protect against sensitization. However, if an individual has become sensitized to 

MDI, an asthma-like response may then result from very low exposures. (See Medical Surveillance section.) 

A teratology study in rats showed fetal and maternal toxicity at 12 mg/m3 of pMDI, with no effects at 

4 mg/m3 . There were no teratogenic effects (malformations) even at the highest exposure tested (12 mg/m3 ). (1) 

Carcinogenicity 

A study to determine the chronic toxicity and potential carcinogenicity of pMDI has been conducted. (2) Rats 

were exposed for two years to an atmosphere of respirable aerosol particles of pMDI at concentrations of 

0, 0.2, 1.0, or 6.0 mg/m3 . These tests require a specialized aerosol generation device. Some, mostly benign, 

lung tumors were observed at the highest exposure concentration. A second chronic inhalation study has 

(1) Gamer et al. (2000). Toxicol Sci. Apr;54(2):431-40 

(2) Reuzel et al. (1994). Fundam Appl Toxicol Feb;22(2):195-210 




been conducted on MDI at 0, 0.2, 0.7, and 2 mg/m3 for 17 hours per day, with findings that corroborated the 

pMDI 6 hour/day study. 

Evaluation of the results of the pMDI study suggests that the incidence of the lung tumors is consistent with the 

chronic irritation and inflammation in the respiratory tract observed throughout the study. The concentration at 

which tumors occurred is well above established guidelines, which have been set to protect workers. It is 

unlikely that tumor formation will occur if the guidelines are met. The ACGIH TLV for MDI is 0.005 ppm 

(0.05 mg/m3 ) as an 8-hour Time Weighted Average (TWA). OSHA requires that exposures be controlled to 

below a PEL of 0.02 ppm (0.2 mg/m3 ) as a ceiling. 

Medical Surveillance 

Post-offer, pre-placement examinations and periodic medical surveillance of employees are essential 

elements in any program designed to ensure the health and safety of those who work with MDI. The postoffer, 

pre-placement examination should include a respiratory health history, a clinical examination, and a 

baseline pulmonary function testing. Where appropriate, regular medical check-ups (including spirometry) 

may aid in the early detection of any respiratory related effects. Individuals with respiratory problems, such 

as asthma or chronic lung disease, may be susceptible to having respiratory problems when exposed to 

MDI. Individual assessments should be made to determine whether an individual can perform his or her job 

without threatening the health or safety of that individual or others. 

Exposure control to prevent sensitization, and medical surveillance to detect sensitization as early as 

possible, are believed to be the most important aspects of MDI safe handling. 

2.6 First Aid Procedures 

All employees working in areas where contact with MDI is possible should be thoroughly trained in the 

administration of appropriate first aid procedures. Experience has demonstrated that prompt administration 

of such aid can be important in minimizing the possible adverse effects of accidental exposure. 

Inhalation 

Promptly move the affected person away from the contaminated area to fresh air. Seek medical attention. 

Keep the affected person calm and warm, but not hot. If breathing is difficult, oxygen may be administered 

by a qualified person. If breathing stops, a qualified individual should give artificial respiration. 

Skin Contact 

In the event of skin contact, wash thoroughly with soap and flowing water (A recent study has indicated that 

corn oil or polyglycol-based cleaners may remove MDI more effectively than soap and water. (3) Cleaning soon 

after contamination was also important). Promptly remove all contaminated clothing (including shoes) while 

washing. If the skin is burned or irritated, seek medical attention. Decontaminate clothing prior to re-use by 

soaking the garments in an 8 percent ammonia solution for one hour prior to laundering with hot water and 

detergent. Destroy all contaminated leather items, including shoes, belts, and watchbands because these 

items cannot be decontaminated. 

Eye Contact 

If liquid MDI comes in contact with the eyes, irrigate immediately and continuously with low-pressure flowing 

water, preferably from an eyewash fountain. Remove contact lenses, if present, and continue eye irrigation 

for at least fifteen minutes. Seek medical attention at once. 

(3) Wester et al. (1999). Toxicol Sci. 1999 Mar;48(1):1-4 


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Ingestion 

In the event MDI is ingested, have the affected person drink large amounts (i.e., 2-3 glasses) of water or milk, 

do not induce vomiting. Immediately transport to a medical facility and inform medical personnel about the 

nature and extent of the exposure. 

Note to Physician: There is no specific antidote for MDI. Care should be supportive and treatment based 

on the judgment of the physician in response to the reaction of the patient. Post-incident checks are needed. 

2.7 Disposal 

Disposal of Waste MDI 

MDI is not a listed hazardous waste under the Resource Conservation and Recovery Act (RCRA). 

The easiest and most convenient way to dispose of waste MDI is to react it with waste polyol to produce a 

low-quality foam, which can then be sold or used as a manufactured product. However, if the foam is to be 

disposed of, it must be done in full compliance with all federal, state and local regulations and requirements 

governing the disposal of such materials. 

It is generally agreed that neither MDI nor the foam products produced from it possess the characteristics of 

a hazardous waste. Thus, according to the federal regulations, low quality foams produced by reacting waste 

MDI with waste polyol may be discarded or disposed of as a non-hazardous waste. However, it should also 

be noted that state regulations may have stricter requirements than federal regulations. In short, some states 

may consider MDI to be a hazardous waste. Be sure, therefore, to check with the appropriate state 

regulatory agencies before disposing of waste MDI or MDI-based polyurethane foams. (CAUTION: The 

MDI/polyol reaction is exothermic, which may cause spontaneous combustion.) 

Another way to dispose of waste MDI is to react the material with a liquid decontaminant. The waste MDI 

should be added slowly or in increments, under mechanical stirring, to the decontaminant, which should be 

contained in an open-top drum. (Note: Be sure this process is conducted in a well ventilated area or 

outdoors.) Allow the reacted material to stand for 48 hour to permit evolved carbon dioxide to escape. 

Finally, the liquid should be decanted and both the solid and liquid products disposed of in accordance with 

all relevant federal, state and local regulation. Again, since MDI is not a RCRA listed hazardous waste, such 

treatment does not require a federal permit. Also, according to federal regulations, the resulting product may 

be disposed of as non-hazardous waste. However, state and local regulation may be more stringent. 

Disposal of Empty Containers 

Drums and IBC’s destined for a scrap dealer, an incinerator, or a landfill should be decontaminated, then 

punctured or crushed to prevent reuse. (Note: Empty MDI drums and IBCs can be decontaminated by filling 

them with water or a decontamination solution (5-10% sodium carbonate) and allowing them to stand 

unsealed for at least 48 hours. Used decontamination solution and rinse water should be disposed of as 

non-hazardous wastes in strict accordance with all applicable federal, state, and local laws and regulations.) 

There are five acceptable procedures for disposing of drums or IBCs that have contained MDI. They may be sent to: 

• a reconditioner for reuse, 

• a scrap metal dealer, 

• incinerated in an approved facility, 

• processed for material reclamation, or, 

• an approved landfill. 




Regardless of the procedure used, however, all drums should be empty (as defined by RCRA, 40 CFR 

§ 261.7) before they leave the MDI user’s facility. (4) (Note: Drums to be sent to a reconditioner may also need 

to be decontaminated. However, since reconditioners use a variety of different techniques to clean drums 

and to prepare them for reuse, the MDI user should consult with the reconditioner before using any drum 

decontamination procedure.) 

WARNING: Under no circumstances should empty drums be burned or cut open with a gas or electric torch, as toxic 

decomposition products may be liberated. 

2.8 Recommended Formulations for Decontaminant Solutions 

Formulation 1 Weight or Volume % 

Water 90-95 

15-20% concentrated ammonia 1 solution 3-8 

Liquid detergent 0.2-5 


Water 90-95 

Sodium carbonate 5-10 

Liquid detergent 0.2-2 


An alcohol (ethanol, isopropanol or butanol) 50 

Water 45 

15-20% concentrated ammonia 1 solution 5 

Formulation 4 

Use Tergitol formulation 

1 Care should be taken when handling ammonia since it is a hazardous material. 

(4) According to 40 CFR § 261.7, an empty container is one that is “drip dry”—i.e., one that has been emptied of all materials which can 

be removed using the practices commonly employed to remove materials from that type of container; e.g., pouring, pumping, or 

aspirating. (Note that the “one inch” residue rule for determining whether a drum is empty applies only to non-flowable products, such 

as very viscous resins.) 


7






Chapter 3: Safety Auditing of Tank Truck Carriers and Bulk Tank Operators 

3.1 Carrier’s Capability: Assessment and Control 

All MDI manufacturers should use the services of knowledgeable tank truck carriers for distributing their 

products. Manufacturers should be sure that the carriers employed are competent and operate to appropriate 

safety standards. Manufacturers should be aware that carriers sometimes will subcontract with another carrier. 

To ensure that a shipper is aware of any such arrangements, a shipper may include a provision in its motor 

carrier contract requiring the shipper’s consent to any subcontract, and establishing appropriate safety criteria. 

3.2 Carrier Safety Audits 

All shippers involved in transporting MDI should undertake safety audits of their tank truck carriers and bulk 

tank operations periodically. This will enable each shipper to verify that the motor carriers employed comply 

with applicable environmental and safety regulations and adhere to general industry safety standards. To 

protect against liability in the event of an accident, shippers should consider seeking an indemnity provision 

in the contract. This would indicate that they are to be indemnified by the carrier in the event the shipper is 

sued because of the carrier’s failure to comply with applicable regulations or general industry safety 

standards or guidelines. 

3.3 Carrier Safety Audit Procedure 

A carrier safety audit protocol and procedure has been produced by the American Chemistry Council to 

be utilized as a guideline in conducting safety evaluations of the carrier. The American Chemistry Council 

guideline may provide useful information that may be the basis of a carrier audit for those engaged in the 

transport of MDI. 

3.4 Meeting Safety and Regulatory Standards 

Auditing does not replace or diminish the basic responsibility of the carrier to ensure that his distribution 

practices meet the appropriate safety, health, and other regulatory standards and potentially hazardous 

substances are properly maintained as required by the various federal, state, and local regulatory statutes 

and regulations. 

3.5 Scope 

While this section deals with bulk transportation, similar care is required in selecting competent carriers 

to transport intermediate bulk and non-bulk packaging. MDI suppliers may wish to consult the American 

Chemistry Council Carrier Safety Assessment and Audit Protocol procedures for this purpose. 


9






Chapter 4: Design and Construction of Transportation Equipment 

and Packaging 

4.1 Rail Tank Cars (RTCs) 

Rail tank cars used for the transportation of MDI must meet the U.S. Department of Transportation’s design 

and construction requirements for the transportation of hazardous materials. These requirements are found in 

49 CFR Part 179. The various subparts of Part 179 describe the requirements for construction material, 

welding, wall thickness, gaskets, valves, valve protection, and venting devices. 

Specific additional recommendations are as follows: 

• All fittings on Rail Tank Cars should be clearly labeled. 

• Tanks should be thermally insulated to minimize temperature fluctuations and provide extra protection in 

the event of fire or other accident. 

• Heating coils should be located on the exterior of the tank. 

• Tanks may be constructed of mild steel. The tanks may be internally lined. 

• Tanks should be fitted with 2-inch connections for vapor return lines. 

• Although the DOT’s Hazardous Materials Regulations permit bottom outlets, diisocyanate producers 

recommend only top outlets. 

• Pressure relief valves should be present and should be set to 75% of the pressure rating of the tank car. 

• If present, vacuum relief valves should be utilized to prevent negative internal pressure and should be set 

to 1 psig. 

• External fittings should have rollover or crash protection so that the tank car will not leak when involved 

in an accident. 

• Thermowells for temperature measuring devices should be present and have the appropriate relief 

devices to prevent spraying of product in the event of a malfunction of the thermowell. 

• Fittings should be available for pressurizing the car with dry nitrogen or dry air to assist in unloading or 

to apply a nitrogen blanket to prevent moisture ingress. 

• To prevent product contamination, it is recommended MDI not come in contact with aluminum, brass, 

copper, zinc, or their alloys. 

4.2 Cargo Tanks (Tank Trucks) and Inter-modal Bulk Tank Containers (ISOTainers) 

Cargo Tanks used for the transport of MDI must meet the design and construction requirements of the U.S. DOT. 

When MDI is shipped in a DOT specification container permitted by 49 CFR Part 173, it must conform to the 

applicable design specifications in Part 178. 

• Each tank must be fitted with a pressure relief device. 

• Each tank should be fitted with vacuum relief devices as prescribed in the appropriate section of the 

DOT’s regulations. 


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• Loading outlets must be equipped with valves and unloading outlets should terminate in a 2-inch diameter 

male quick connect fitting with proper closure cap. 

• The vapor return valves should be 2-inch diameter and terminate in a quick connect fitting with proper 

closure cap or plug. 

• The air-line valve should be 3/4-inch and terminate in a Chicago coupling with proper closure cap or 

plug. 

• It is very important to prevent atmospheric moisture from entering the tank during off-loading. Dry nitrogen 

is preferred for pressure off-loading. When dry nitrogen is not available, a tank may be pressurized 

using air from the tractor compressor or other source, provided it moves through a desiccant dryer at 

the proper CFM prior to entering the tank. The desiccant drier must be capable of drying the air to a 

dew point of -40ºF. All customer-supplied air or nitrogen should be routed through the carrier’s desiccant 

dryer. 

• Heating systems, when used, should be external and equipped with a temperature indicator (manual or electronic). 

• Off-loading hoses should be 2-inch diameter, color-coded red, and stamped “For Diisocyanate Use 

Only.” Materials of construction should be suitable for diisocyanates. The hoses should be clean, dry 

and capped when not in use. Pressure testing is recommended prior to their first use and at least quarterly 

thereafter. 

4.3 Intermediate Bulk Containers (IBCs) 

IBCs are not recommended for the transport of monomeric MDI owing to its relatively high freezing point. 

However polymeric MDI is normally shipped in a variety of intermediate bulk containers. 

Most IBCs are of a size that would limit the capacity to less than 5,000 pounds of 4,4’MDI, thus excluding 

them from being subject to the DOT hazardous material regulations. However, if shipped in an IBC that contains 

more than 5,000 pounds of 4,4’MDI, the shipper must comply with all applicable DOT hazardous material 

regulations. Even if shipped in quantities of less than 5,000 pounds, it is recommended that DOT safety 

procedures and standards be followed. 

4.3.1 Filling Standards 

Before being filled and offered for transportation, each IBC and its service equipment must be visually 

inspected to ensure that it is free from any damage that would render it unsafe for transport (49 CFR 

§173.35.) 

When filling an IBC with liquid, sufficient headspace (ullage) must be left to ensure that, at the mean 

bulk temperature of 50ºC (122ºF), the IBC is not filled to more than 98% of its water capacity (49 CFR 

§ 173.35(d)). 

4.3.2 Construction and Performance Standards 

Construction requirements for IBCs are specified at 49 CFR Part 178 Subpart N. Containers handling 

regulated amounts of MDI must satisfy the following performance tests, which are detailed in Part 178, 

Subpart O: 

• Vibration; 

• Bottom lift and/or top lift (depending on how the container is intended to be handled); 




• Stacking; 

• Leakproofness (liquids only); 

• Hydrostatic (liquids only), and 

• Drop tests. 

Each container must be visually inspected, tested for leakproofness, and marked with the retest date 

(if used for transporting liquids) every 2.5 years from the date of manufacture (49 CFR §180.352). 

4.3.3 Record keeping 

The person certifying the testing of an IBC in Hazardous Materials service must keep records of periodic 

retests and initial and periodic inspections. Records must include: 

• Design types and packaging specifications; 

• Test and inspection dates; 

• Name and address of test and inspection facilities; 

• Names of persons conducting tests or inspections; and 

• Test or inspection specifics and results. 

Records must be signed by the person conducting the test and must be kept for each packaging at 

each location where periodic tests are conducted. These records must be kept until such tests are 

successfully performed again or for 2.5 years from the date of the last test. 

4.4 Drums 

MDI is not classified as a hazardous material by the DOT if shipped in a single container in quantities less 

than 5,000 pounds. Thus, MDI is not regulated in drums. However, in accordance with their commitments to 

Responsible Care ® , MDI producers typically ship MDI in packaging that satisfies stringent DOT performance 

tests designed to ensure that packaging integrity will be maintained. 

[Although drum shipments of MDI are not regulated by the DOT, producers generally voluntarily comply with the relevant 

modal transport regulations for road (49 CFR), rail (49 CFR), air (49 CFR or ICAO/IATA), sea (IMDG) or inland 

waterway (33 CFR). The producers recommend that drums be constructed in conformance with the standards 

applicable for the particular material of construction (i.e., steel, plastic, and fiberboard). See 49 CFR § 178.505-509.] 

[Additionally, the producers recommend that drums must meet the performance tests prescribed in the regulations. 

See 49 CFR §§ 178.600-178.608. See Appendix 5. These regulations also include a provision that the 

drums bear certification marks indicating compliance with the UN performance oriented packaging standards 

to the appropriate product density and hazard level. 49 CFR § 178.503.] 

4.4.1 Drum Specifications 

Materials of construction of the drum and all fittings and gaskets must be compatible with the product. 

49 CFR § 173.24(e). Drums must be inspected for integrity, tightness, dryness, cleanliness and 

absence of rust or foreign particles before filling. See 49 CFR § 173.22(a)(2). Additionally, all diisocyanate 

producers agree that open head type drums should not be used for PMDI products due to the 

potential for leakage and/or contamination. 


13



4.4.2 Drum Handling 

Personal Protective Equipment 

Persons handling drums should have the proper personal protective equipment. See Chapter 6. 

Transporting Drums 

Drums should be transported by lifting, to avoid damage caused by sliding or rolling. Only equipment 

designed for handling drums should be used, such as fork-lift trucks equipped with “parrot beaks” or 

drum clamps (CAUTION: Drum clamps should not be used on the Euro “W” style drum now used by many 

diisocyanate suppliers). Once loaded/unloaded, the responsible party should examine the drums to 

check for damage or leaks. If any drums are found to be leaking, the procedures for spill response 

should be followed. 

Emptying Drums 

Drums may be gravity discharged or emptied using a standard immersion pump. Air displaced from 

the receiving tank should be discharged to a vapor exhaust system. A silica gel filter may be 

connected to the open drum vent to prevent drums from collapsing while being emptied. This also will 

prevent moisture from entering the drum. The opening of drums should be minimized to reduce 

moisture contamination. 

Caution: Contamination Problems 

Water contamination of drums should be avoided. MDI reacts with water to generate CO2 gas, which 

can cause a potentially dangerous pressure build-up in the container. This reaction is accelerated at 

high temperatures (120ºF). Drums showing evidence of pressure build-up should be vented 

immediately, with caution; otherwise there is a potential for a violent drum rupture. Should such 

evidence be observed, contact your manufacturer immediately for proper handling procedures. 




Chapter 5: HazMat Training 

5.1 Training Requirements 

All employees involved in preparing for transport, and in transporting quantities of MDI at or above 5,000 

pounds are required to be HazMat trained, pursuant to 49 CFR §§ 172.700-704. Training of new employees 

must be completed within 90 days of placement in any job requiring such training, and must be repeated at 

least every 3 years. Further, employees should be advised of changes in the law that occur during that time 

that affect their job performance. All HazMat employees must be trained in each of the following areas: 

• General Awareness 

• Function Specific 

• Safety 

Additionally, employees must receive OSHA safety training and may be required to receive training in EPA 

release reporting and response. Drivers may also need to obtain a hazardous materials endorsement on their 

Commercial Drivers License. 

Records must be maintained on all personnel who receive DOT training, both supervisory and non-supervisory 

personnel. Each employee must have his or her own training log (the formal record) inclusive of the preceding three 

years. The employer must retain the training log for as long as that employee is employed and for 90 days thereafter. 

5.2 Specific Requirements for MDI 

Because MDI is a DOT-regulated hazardous material at or above 5,000 pounds, drivers must be specifically 

trained to understand the particular nature of the dangers that may arise during the transport of this material 

and how to handle an emergency. A guideline for drivers is included in Appendix 2. Under DOT’s regulations, 

an employer whose employees are involved in handling hazardous materials is responsible for ensuring that 

they are properly trained. See 49 CFR §§ 172.700-704. This means that both shippers and carriers are 

independently responsible for ensuring compliance with the training requirements. 

5.3 Driver Criteria for Transporting MDI 

Before a driver is allowed to transport a regulated material like MDI, he must have: 

• Received training to the standard required by federal, state and local regulation and obtained a 

Commercial Drivers License (CDL) and a Hazardous Materials endorsement on his/her license as 

required by 49 CFR §§ 383.71- 383.155. 

• Received MDI specific training as part of his required function-specific training. 

5.4 Certified Drivers 

Before a shipper enlists a carrier he should: 

• Ensure that the carrier can document that all drivers transporting MDI have been trained in accordance 

with DOT’s regulations. 

• A shipper should include training as an item to be addressed in the carrier audit program mentioned in 

Sections 3.2 to 3.5. 


15






Chapter 6: Personal Protective Equipment for Loading or Unloading MDI 

When transferring MDI, personal protective equipment should be worn by employees and/or drivers engaged 

in these activities if the possibility of exposure exists. This may, depending upon conditions, consist of: 

• Chemical goggles; 

• Face shield; 

• Chemical gloves, resistant to MDI (5) ; 

• Long-sleeve coveralls or full body suit, resistant to MDI (5) ; 

• Fitted boots made of material(s) resistant to MDI (5) , and; 

• Head protection, such as a close fitting hood, made of a material resistant to MDI (5) . 

Taking samples for quality control analysis during off-loading is not recommended. 

The use of suitable respiratory equipment is recommended whenever there is a potential for handling MDI at 

elevated temperatures (above 120ºF) or in the presence of unknown airborne concentrations. 

For additional information on Personal Protective Equipment (PPE) refer to the manufacturer’s Material Safety 

Data Sheet. 

(5) See API protective glove/clothing permeation data—MDI User Guidelines for Chemical Protective Clothing Selection (AX-178). 


17






Chapter 7: Loading Operations 

7.1 Compliance With Transport Regulations 

The shipper and the carrier should work together to ensure compliance with transport regulations. 

7.2 Criteria for Loading Facilities and Transport Equipment 

The act of filling any container with a hazardous material is potentially dangerous. It is therefore important 

that loading facilities and transport equipment be correctly designed and constructed, as well as properly 

used and well maintained. 

7.3 Design and Construction of Transport Equipment 

The design and construction of transport equipment is described in Section 4 of these Guidelines. Equipment 

used in the transportation of MDI is subject to periodic inspection and testing requirements by the carrier as 

specified in DOT’s regulations. 

7.4 Availability of Written Operating Instructions 

Written operating instructions should be made available covering the loading of MDI into bulk tank trucks, intermodal 

tanks and containers, rail tank cars, multi-unit tank car tanks, intermediate bulk containers (IBC 

totes/cylinders), and non-bulk packaging. Additionally, persons involved in shipping quantities of MDI in a single 

package at or above the 5,000 pound RQ must be fully trained in accordance with DOT’s hazardous materials 

regulations. Information regarding the specific hazards of MDI must be communicated to all individuals involved 

in the loading/unloading or transportation of MDI above the RQ. 49 CFR § 172.600. Additionally, such persons 

must be trained in the proper procedures for the operation of the filling equipment in both normal operations 

and in any emergency situations (see Section 11.3 for further relevant details). Drivers also must be familiar with 

safety procedures, including the use of safety equipment at the loading point. See 49 CFR § 172.704(a)(3). 

7.5 Availability of Personal Protective Equipment 

Appropriate personal protective equipment must be available for loading operations and persons must be 

trained in the correct use of this equipment. See 29 CFR § 1910.132. Whenever the driver leaves his vehicle, 

he should take with him the appropriate personal protective equipment to ensure its availability in the event 

of an emergency. See Chapter 6. 

7.6 Inspection of the Bulk Transport Equipment 

These Guidelines do not attempt to set detailed operating instructions for filling MDI containers since these, of 

necessity, will depend upon local operating conditions. However, the operating instructions should specify that 

loading personnel inspect the bulk transport equipment before, during and after loading. This inspection does not 

replace or diminish the responsibility of the operator of bulk transport equipment to ensure that it is properly 

tested, maintained, fit for its intended purpose and ready for loading. It is meant to ensure that the loading and 


19



unloading of MDI is conducted as safely as possible. The inspection list detailed below is a guideline which 

loaders may use to check the condition of the bulk transport equipment before and after all filling operations. 

Individual companies should develop their own detailed operating instructions that include inspection procedures. 

7.6.1 Routine Inspection of Tank Trucks and Inter-modal Bulk Tank 

Containers (ISOTainers) 

Administrative Procedures 

The shipper should verify that: 

1. The loading personnel have received DOT HazMat training, if required. 

2. The driver has a valid CDL and, if necessary, a HazMat endorsement and has been trained to 

handle MDI. 

3. The vehicle capacity is adequate for the quantity to be loaded and, when loaded, the total gross 

weight is within regulatory limits. 

4. The driver has been provided with the appropriate shipping documentation and emergency 

response information. 

Before loading 

The shipper should have a comprehensive pre-loading procedure that includes, as a minimum, 

verification that: 

1. The unit is in compliance with all required DOT inspections. 

2. All closures are properly secured upon arrival. 

3. The tank has been inspected and found suitable for loading. 

4. Proper markings and identification numbers for MDI (NA3082) are attached after loading. 

5. The vehicle has all the necessary specific equipment in proper working condition, including: 

• DOT standard equipment 

• Air-dryer, compressor, insulation, heating device, safety relief valves (pressure and vacuum), 

pressure gauge, temperature gauge, vapor return connection and sampling valve, if required 

6. All valves have been checked for freedom of movement and are fully closed. 

7. The person in charge of the loading operation has been notified of the quantity to be loaded. 

During loading 

1. The loading operation should be monitored continuously. 

2. Loading personnel should ensure that specified filling levels are not exceeded. 

After loading 

The shipper and driver should verify: 

1. The maximum permitted gross weight for the vehicle has not been exceeded. 

2. All the valves, blind flanges and domes have been closed and secured properly. 

3. The exterior of the tank is clean and free from product residue. 

4. The appropriate marking and identification number have been applied. 

5. The tank truck is equipped with all required hoses and fittings necessary for unloading. 




7.6.2 Routine Inspection of Rail Tank Cars 

Administrative Procedures 

The shipper should verify that: 

1. The rail car is DOT approved and authorized for MDI transport. 

2. The safety valve and tank test dates are current. 

3. The carrier has been provided with the appropriate shipping documentation and emergency 

response information. 

Before loading 

The shipper should have a comprehensive pre-loading procedure that includes, as a minimum, 

verification that: 

1. The rail car is in good physical condition and is safe to transport MDI. 

2. All the valves and domes are properly secured. 

3. The rail car capacity is adequate for the quantity to be loaded. 

4. The rail car has all the necessary specific equipment and is clean, dry, and in proper working condition. 

5. All valves function correctly. 

During loading 

1. The loading operation should be monitored continuously. (49 CFR § 174.67) 

2. Loading personnel should ensure that specified filling levels are not exceeded. 

After loading 

The shipper and driver should verify: 

1. The maximum allowable gross weight for the vehicle has not been exceeded. 

2. All the valves, blind flanges and domes have been closed, are secured properly, and leak free. 

3. All seals or locks are in place. 

4. The exterior of the tank is clean and free from product residue. 

5. The proper markings and identification numbers for MDI (NA3082) are affixed. 

7.6.3 Maintenance of Transport Equipment 

During operation, unscheduled maintenance of the transport equipment may be necessary. The chemical 

reaction of MDI with water in the atmosphere leads to the formation of urea, which could plug the valves 

and block the pressure relief valves and piping. Customers should be instructed to immediately report 

any difficulties to the shipper and to their maintenance department. One means of communicating is to 

attach an information tag identifying problems to the returning transport equipment. 


21



7.7 Inspection List: Modifications 

The inspection list assumes that MDI is to be loaded and transported domestically. In circumstances where 

MDI is to be shipped internationally—in accordance with regulations that may differ from the requirements of 

the DOT—the inspection list should be modified as appropriate. 

7.8 Additional Inspections 

In addition to the routine inspection of all bulk transport equipment, prior to each loading operation or 

reintroduction after maintenance or repair, each tank truck, inter-modal container tank, or rail tank car should be 

thoroughly inspected prior to its initial introduction or reintroduction, into service after maintenance or repair. 




Chapter 8: Transport of MDI by Rail 

8.1 Responsibilities of Rail Carrier 

Rail carriers are responsible for the safe transport by rail from dispatch siding to final reception siding. 

See 49 CFR Part 174. The selection of the routes, intermediate stopping locations, and cessation of traffic 

because of severe weather conditions are matters to be decided by the railway authorities, and should be 

reported to the shipper. 

8.2 Emergency Intervention 

The relevant federal, state or local authorities may intervene in the event of a transport emergency involving 

rail tank cars containing MDI. Shippers must provide rail tank carriers with the appropriate emergency 

response information, along with a 24-hour contact number. See 49 CFR §§ 172.600-604. 

8.3 Inter-modal Movements 

Where inter-modal (i.e., road/rail/road) movements are arranged that are not driver/tractor accompanied 

during the rail stage, particular attention must be given to ensuring that the motor carrier leg of the journey 

has the appropriate shipping and emergency response information. 


23






Chapter 9: Transport of MDI by Road 

The carrier is responsible for the safe transport of MDI by road from the loading point to the discharge (unloading) 

point. The following summarizes basic regulatory provisions and highlights industry recommendations. 

9.1 Routing 

The route to be followed must be selected carefully by the carrier and should be given, upon request, to the 

shipper. Compliance with bridge, tunnel or local routing regulations and restrictions is the responsibility of the 

carrier. DOT requires carriers of hazardous chemicals to: 

• utilize routes that follow major highways and/or designated truck routes, and; 

• avoid areas of high population density. 

Exceptions to the above restrictions are permissible only where “there is no practicable alternative.” See 49 

CFR § 397.9. 

9.2 Safe Parking 

Motor vehicles containing hazardous materials (with the exception of explosives which are treated separately) 

must not be parked on or within five feet of the traveled portion of a public street except for brief periods when the 

“necessities of operation require the vehicle to be parked and make it impracticable to park the vehicle in any 

other place.” See 49 CFR § 397.7. A secure depot or secure factory premises should be used whenever possible. 

Preferably, parking should be in an isolated location that is illuminated at night. It is strongly recommended that 

receivers provide secure parking to vehicles that have arrived outside specific access times. 

9.3 Severe Weather Conditions 

When severe weather conditions exist (i.e., icy roads, snow or poor visibility) that may affect the ability of the 

driver to proceed safely with the shipment, the vehicle should stop at the first suitable parking place. The 

driver should not continue with the delivery until the weather conditions improve. See 49 CFR § 392.14. 

9.4 Delays or Accidents 

All delays during transport, whether caused by severe weather conditions, breakdown or any other reason, 

should be reported to the shipper as soon as possible. In the event of an accident during the journey 

involving the immobilization of the vehicle, product spillage, or threatened loss of containment, the driver 

must contact the 24-hour emergency contact number, and follow any procedures specified in the emergency 

response information provided by the shipper. In addition, details of the accident must be reported to DOT in 

accordance with DOT’s reporting requirements. See 49 CFR § 171.16. 

Also, the U.S. Environmental Protection Agency considers MDI a hazardous substance. Thus, if more than 5,000 

pounds of MDI is spilled or otherwise released into the environment, the shipper is responsible for immediately 

reporting the release to the National Response Center and the local 911 operator. See 40 CFR §§ 302.6 and 355.40. 


25



9.5 Inspections During Transport 

Under the DOT’s regulations, a driver must examine the vehicle’s cargo and its load-securing devices within 

the first 25 miles after beginning a trip and make any adjustments to the cargo or load-securing devices 

(other than steel strapping) as may be necessary to maintain the security of the commercial motor vehicle’s 

load. 49 CFR § 392.9(b)(2). The truck driver then must periodically examine the vehicle's cargo during the 

course of transportation as follows: 

• when the driver makes a change of duty; 

• after the vehicle has been driven for 3 hours; or, 

• after the vehicle has been driven 150 miles, whichever occurs first. 49 CFR § 392.9(b)(3). 

For the bulk transport of MDI, the temperature of the tank contents should be checked regularly (detailed above) 

and recorded manually or electronically. If the temperature of the tank contents should rise more than 10ºF above 

that specified by the shipper, the driver should immediately telephone the shipper to seek instruction. 




Chapter 10: Transport of MDI by Water Vessel 

10.1 Approved Containers 

MDI may be transported by ocean vessel as follows: 

• Inter-modal tank containers, by roll on/roll off chassis; use of a 40 foot drop-nose type is recommended. 

• Inter-modal tank containers that are lifted on/off of container vessels. 

• In bulk ocean tankers or inland waterway vessels (not covered by these guidelines. See Chapter 1.5). 

• In intermediate bulk containers, which should be transported in freight containers. 

• In non-bulk packaging such as drums, which should be transported in freight containers. 

10.2 Parties Involved 

Because of the nature of the activity, a number of different parties may be involved in transporting MDI from 

shipper to customer. These may include shipping companies, freight forwarders, port or harbor authorities, 

and carriers. 

10.3 Safety Audits 

The shipper should consider carrying out a safety audit of the following distribution operations: 

• Forwarding operators; 

• Loading and unloading facilities at container terminals; and, 

• Emergency handling within hazardous cargo yards and container terminals. 


27






Chapter 11: Unloading Operations for Tank Trucks and Rail Tank Cars 

11.1 Criteria for Discharge Facilities 

The operation of discharging MDI from any bulk container may present risk of certain physical and health 

hazards. Consequently, it is important that discharge facilities be correctly designed and constructed, and 

properly used and maintained. 

11.2 Design, Location and Checks 

Discharging facilities should be designed and located for the handling requirements associated with MDI. 

A preventive maintenance program covering all equipment should be developed to ensure proper operation 

(See Appendix 3). 

11.3 Criteria for Discharge 

Off-loading hoses and vapor return hoses should be 2-inch diameter, color-coded red, and stamped “For 

Diisocyanate Use Only.” Materials of construction should be suitable for diisocyanates. The hoses should be 

clean, dry and capped when not in use. Pressure testing is recommended prior to their first use and at least 

quarterly thereafter. Two-inch diameter hoses are the recommended industry standard for unloading MDI and 

for vapor exchange. 

11.4 Operating Procedures 

Written operating procedures should be prepared covering all aspects of the discharge of MDI. In the case of 

tank truck unloading, the division of responsibilities between the driver and receiver should be clearly 

defined. See Appendix 2 for specific recommendations on the division of responsibilities between the tank 

truck driver and the receiver. See Appendix 3 for specific recommendations for unloading from a rail tank car. 

Reference 49 CFR § 177.834 for attendance requirements for tank truck unloading and 49 CFR § 174.67 for 

rail car unloading. 

11.5 Protective Equipment for Operators 

All necessary personal protective equipment should be available for discharging operations (See Chapter 6 

for further details). Persons must be trained in the correct use of this equipment. Whenever the driver of a 

tank truck leaves his vehicle, he should take with him the appropriate personal protective equipment to be 

sure of its availability in the event of an emergency. 

11.6 Inspection of the Bulk Reception Facilities 

The customer is generally responsible for controlling the conditions of receipt. Customers should work with 

their suppliers to ensure that good safety standards have been developed for handling and storage. See 

Appendix 4 for a checklist of general industry recommendations that provides companies with guidelines for 

ensuring the safe handling and storage of MDI. 


29






Chapter 12: Required Shipping Information for MDI 

12.1 MDI’s Hazardous Materials Classification 

When in transport in a single package above the RQ, MDI is classified as a Division 9, Packing Group III 

Environmentally Hazardous Substance or Other Regulated Substance. This classification triggers a number 

of regulatory requirements when a company offers a material for either domestic or international shipment. 

The principles of DOT hazardous materials regulations are as follows: 

• A company offering MDI for transport above the RQ, must complete a shipping paper indicating the required 

shipping information for MDI. 49 CFR §§ 172.200-.203. This information varies slightly depending on 

whether the material is moving in domestic (U.S.) or international commerce. See subsection 12.2 below. 

• The shipping paper must include an emergency contact telephone number that is manned twenty-four 

hours a day. See 49 CFR § 172.604. (Within the U.S., all major producers are members of a mutual aid 

program known as CHEMTREC, which is available through the American Chemistry Council). 

• The shipping paper must include the required shipper’s certification that the material is shipped in 

compliance with the regulations. See 49 CFR § 172.204. 

• Emergency response information must be provided to the carrier. See 49 CFR §§ 172.600-602. 

• As required by DOT’s regulations, MDI shipped in a package about its RQ must be appropriately: 

– packaged (49 CFR § 173.243 (bulk) and 49 CFR Part 178); 

– marked (49 CFR §§ 172.300-338); 

– labeled and placarded (49 CFR §§172.300-338; 49 CFR §§ 172.400-448; and 49 CFR §§172.500-560). 

12.2 Summary of MDI Hazard Information* 

DOT (applicable if MDI is shipped in a package in an amount greater than 5,000 pounds) 

Proper Shipping Name Other Regulated Substances, Liquid, n.o.s. or Environmentally Hazardous Substances, 

Liquids, n.o.s. 

Hazard Class 9, Miscellaneous Hazard 

U.N. Number None 

Other Regulated Substances 

Environmentally Hazardous Substances 

NA3082 

Packing Group III 

Reportable Quantity** 5,000 lbs. 

Label/Placard 3082 

IMDG*** 

ICAO*** 

*** Information in italics should be entered on the shipping paper in the order shown. Other information is provided for easy reference. 

*** Shipments of MDI exceeding 5,000 lbs. in one container must have the letters “RQ” entered on the shipping paper and marked on the packaging. 

*** This agency does not regulate MDI as a hazardous substance. 


31



12.3 Preparedness and Emergency Response 

Shippers should be prepared to provide on-scene assistance and expert advice in remedial action 

procedures. In cases where local, state or federal authorities are in control of the incident, the role of the 

company responders should be to: 

• Operate fully within the company’s Site Specific Emergency Response and Safety & Health Plan. 

• Assist in the establishment of an Incident Management System and provide technical advice based upon 

product knowledge to the On-Scene Command (OSC). 

• When conditions warrant, and as requested by the OSC, organize the provision of spare 

vehicles/pumps/hoses/other equipment for the cargo transfer and decontamination; and, be prepared, 

on behalf of the OSC, to employ their technical expertise in conducting or supervising remedial action. 

12.4 Principles of Emergency Response Scheme 

The principles of the scheme should be: 

• If the producer cannot respond promptly to an incident that requires on-scene assistance, the producer 

may request a nearby chemical company to respond. If another company cannot respond, the shipper 

may seek a for-hire response company. 

• Only chemical companies and for-hire responders that are qualified to handle the hazards of MDI 

involved in the incident will be requested to respond. 

• Response by a chemical company to another shipper’s incident is discretionary. 

• The producer will, upon request, reimburse the responding company for reasonable expenses, or pay a 

for-hire company in accordance with the current schedule of charges in effect under their contract. 

• All companies participating in these arrangements will make available such services and assistance as 

would be provided for their own MDI. 

12.5 Technical Communications 

Regular technical communications should be established between participating companies in order to 

recommend methods of approach in the resolution of transportation/distribution incidents. 




Appendix 1: Sample Certificate of Receipt 

Part A: (To be completed by the receiver of bulk tank truck loads BEFORE discharge is started) 

I hereby certify that the following has occurred: 

• The MDI can be safely received by the storage facility. 

• The MDI to be received is the same as described on the bill of lading. 

• The unloading arm or hose is connected to the correct lines and/or piping and unloading may begin. 

• Room to hold quantity being delivered. 

Signature ........................................................ Date ................................... 

Part B: (To be completed by the receiver of bulk loads AFTER discharge is started) 

I certify that the item shown on the bill of lading has been received. 

Signature ........................................................ Date ................................... 

* This document is provided for guidance purposes only, as one way of verifying that MDI has been received and properly unloaded. 

Individual company practices may vary. 


Appendix 1-1



Appendix 1-2 Copyright 2001, American Plastics Council



Appendix 2: Guidelines for the Unloading of Tank Trucks 

(A Suggested Checklist) 

This Appendix contains guidance for off-loading tank trucks with a suggested division of responsibilities 

between the driver and receiver. Because of variations in the configuration of a customer’s facilities, the 

specific activities involved, or the sequence in which they are conducted, may differ from what is described 

in this Appendix. 

The purpose of this Appendix is to demonstrate the complexity of the operation and the need for a clear 

understanding of the division of responsibility between those involved. 

The driver has a legal duty to protect the integrity of a hazardous material. The receiver has a duty to ensure 

that product is safely discharged into the proper tank. Both should cooperate fully in the discharge process to 

ensure that it is conducted safely. 

U.S. Department of Transportation’s regulation under 49 CFR § 177.834 requires that throughout the entire 

period of unloading and while the tank truck has unloading equipment attached, a qualified person must attend 

the cargo tank unloading process to ensure safety. The current DOT attendance requirements demand “physical 

on-site attendance by a person who is alert, is within 25 feet and has an unobstructed view of the unloading 

operation.” 


Appendix 2-1



Suggested Checklist for Tank Truck Unloading 

Receiver Activities 

1 ____ Verify your facility expects to receive a 

delivery. 

3 ____ Direct the tanker to the unloading point. 

4 Verify: 

____ the amount to be unloaded can be 

accepted in the storage tank. 

5 Verify: 

____ the product name on the bill of lading is 

what you are expecting to receive. 

____ the same tank/truck number appears on 

the bill of lading, packing list and COA. 

____ the proper unloading connections for this 

product. 

8 ____ Secure area with signs or barricades. 

9 Tell the driver where to find: 

____ the shower. 

____ the eyewash. 

____ the fire extinguisher. 

Driver Activities 

1 ____ Drive to the receiving area. 

2 Give the receiver: 

____ bill of lading. 

____ packing list. 

____ certificate of analysis. 

____ scale ticket. 

6 ____ Position vehicle as directed by the receiver. 

7 Prepare vehicle for unloading: 

____ apply the brake. 

____ chock wheels with 2 chocks. 

____ shut off tractor engine unless required to 

off-load 

____ show unloader the location and operation 

of the tank truck emergency shut-off. 






If the receiver participates in unloading: 

10 Put on personal protective equipment: 

____ chemical goggles and/or full-face shield. 

____ chemical gloves, impervious to MDI*. 

____ long-sleeve coveralls or full body suit, 

impervious to MDI*. 

____ fitted boots made of material(s) 


____ head protection, such as a close fitting 

hood, made of material impervious to MDI*. 

11 ____ Make sure that all valves in receiving 

system are fully closed. 

13A ____ Take sample to laboratory if required. 

13B ____ Inspect the hose and gaskets prior to 

connection. 

14A ____ Connect the unloading hose to the 

storage facility. 

15A ____ Record start level in storage tank. 

15B ____ Sign the drivers Bill of Lading that a good 

hook up has been made. 

16 ____ If the product conforms to specification, 

start the unloading procedure. 

17 ____ Check driver’s action. 



10 Put on personal protective equipment: 

____ chemical goggles and/or full-face shield. 

____ chemical gloves, impervious to MDI*. 

____ long-sleeve coveralls or full body suit, 


____ fitted boots made of material(s) 


____ head protection, such as a close fitting 

hood, made of material impervious to MDI*. 

11 ____ Make sure that all vehicle valves are 

fully closed. 

12 ____ Take sample if required (not recommended). 

13A ____ Inspect the hose, fittings, and gaskets 

prior to connection. 

14A ____ When required by the customer, the driver 

may connect the unloading hose providing 

the customer signs the statement on the 

carriers Bill of Lading mentioned in 

appendix 1, part A, pg 1-1. 

14B ____ Assist receiver and connect hose to 

tank truck. 

15B ____ Ensure the customer has signed the 

carrier Bill of Lading indicating a good 

hook up has been made. 

For Pump Discharge Only: 

18A ____ Install the vapor return line connection to 

the vehicle. 

* See API protective glove/clothing permeation data—MDI User Guidelines for Chemical Protective Clothing Selection (AX-178). 

Appendix 2-3





19A ____ Open valves in the customer’s unloading 

and vapor piping. 

20 For Pressure Discharge Only: (in sequence) 

A ____ Open vent line on storage tank. (Vent line 

must be connected to an effective 

scrubber system such as an activated 

carbon canister of sufficient capacity, 

installed and maintained in accordance 

with manufacturer’s recommendations.) 

B ____ Keep vent line open throughout product 

transfer. 

C ____ Connect dry air or nitrogen supply to the 

trailer and open valves to pressurize the 

trailer. 

D ____ Open the nitrogen supply valve, or if dry 

air is used, open air valve and start air 

compressor. 

E ____ When proper pressure has built up in the 

tank truck, open the valve on receiver’s line. 

21A ____ Observe and control the transfer including 

product level in the receiving tank. Any 

anomaly linked to product discharge 

systematically implies: 

____ stopping the discharge. 

____ immediately informing the management 

and seeking instructions. 

____ recording the incident. 


18B ____ Ensure valves on the vapor return line 

are open. 

19B ____ Open tank truck internal valve, and check 

the system to ensure no leaks. 

20F ____ Open tank truck outlet (external) valve 

and check the system to ensure no leaks. 

21B ____ Attend the vehicle during transfer to 

observe and assist in any emergency. 






22 When the transfer operation is complete: 

For Pump Discharge Only: (in sequence) 

A ____ Manipulate hose to provide gravity flow 

to pump enhancing hose drainage. 

B ____ Close valve on receiver’s line. 

C ____ Stop pump. 

D ____ Close valve on vapor return line. 

For Pressure Discharge Only: (in sequence) 

23A ____ Close nitrogen supply valve or shut off air 

compressor and closes dry air valve. 

B ____ Close valve on receiver’s line. 

C ____ Close vent line on storage tank. 

24A ____ Bleed pressure off then disconnect the 

unloading hose; cap and plug and stow 

away safely. If using carrier hoses as 

recommended, this is a driver activity. 

25A ____ Secure unloading line connections. 



A ____ Driver assists. 

22E ____ Close tank truck external valve. 

F ____ Close tank truck internal valve. 

G ____ Close tank truck vapor exchange valve. 

B ____ Ensure the unloading hose has been 

blown empty. 

23E ____ Close internal valve. 

F ____ Close tank truck external valve. 

24A ____ Driver assist. We recommend carrier 

supplied hoses. 

25 ____ Secure trailer connections. 

Appendix 2-5





26 ____ Remove personal protective equipment, 

carefully cleaning any items contaminated 

during the discharge process. 

____ Record stop level in storage tank. 

27 ____ Sign drivers bill of lading and paperwork. 

28 ____ Leave the transfer point. 


26 ____ Remove personal protective equipment, 

carefully cleaning any items contaminated 

during the discharge process. 

28 ____ Leave the transfer point. 




Appendix 3: Guidelines for the Unloading of Rail Tank Cars 

(A Suggested Checklist) 

This appendix contains guidance for off-loading rail cars into storage tanks. Because of variations in the 

configuration of a customer’s facilities, the specific activities involved or the sequence in which they are 

conducted may differ from that described in this appendix. 

Methylene Diphenyl Diisocyanate is typically shipped in DOT 111A100 W2, general purpose rail tank cars 

that normally have a baked phenolic lining and external insulation. 

U.S. Department of Transportation regulation 49 CFR § 174.67 requires that throughout the entire period of 

unloading and while the tank truck has unloading equipment attached, a qualified person must attend the rail 

tank car unloading process to ensure safety. 

The following satisfy DOT attendance requirements: 

• Physical on-site attendance by a person who is alert and has an unobstructed view of the unloading 

operation. 

• A signaling system that includes surveillance equipment (television monitors and video cameras) with 

remote shut-off equipment. This equipment must be monitored at all times either in the 

immediate area of the rail tank car or from a remote location “within the facility.” 

• A signaling system that includes sensors that provide immediate notification of a system malfunction 

(e.g., presure reduction, leakage, hose or line rupture, and detection of minute levels of fumes or 

vapors) or other emergency so that, if warranted, the product flow may be immediately halted. 


Appendix 3-1



Suggested Checklist for Rail Tank Car Unloading 

1 ____ Refer to the manufacturer’s Material Safety Data Sheets (MSDS) and their technical literature for 

further information. 

2 ____ Spot rail car in a level position. 

3 ____ Chock wheels. 

4 ____ Set derail and hand brake. 

5 ____ Post blue flag “STOP—MEN AT WORK” or “STOP—TANK CAR CONNECTED” sign on tracks. 

6 ____ Inspect rail car to make sure it is equipped with the following: 

• equalization valve. 

• nitrogen valve. 

• 2" top and/or bottom unloading valve. 

• pressure relief valve. 

• verify dome bolts are tight. 

• verify that seals are unbroken. 

7 ____ Verify that the proper car is on the unloading spot. Carefully check the contents shown on the bill 

of lading or other documented means (for example: supplier’s certificate of analysis) to verify that 

the proper product is being offloaded. 

8 ____ Check rail car placard for proper identification number (for MDI, this number is 3082). 

9 ____ Record initial level on MDI storage tank to verify that it has enough capacity for the entire 

contents of the car. STORAGE TANK LEVEL: _________ lbs. 

10 ____ Check the rail car for the required transfer temperature. 

• the temperature of the contents can be adjusted by use of the car's heating coils or 

circulating steam or hot water through the car’s external heating coils. 

• consult the supplier if MDI has been frozen. (MDI freezes at approximately 55ºF) 

11 ____ Check for the required pressure inside the rail car. 

• if the nitrogen pad has leaked out, contact supplier for further instructions. 

12 ____ Check to ensure that an adequate amount of MDI neutralizer (used for spill cleanup) is available in 

the immediate area. If necessary, make up additional neutralizer batch following the instructions in 

Addendum 5, Appendix 11. An emergency spill cart should be available in immediate area. 

13 ____ Locate the following and verify proper operation: 

• nearest safety shower and eyewash. 

• telephone or intercom. 

14 ____ Put on personal protective equipment that has been tested and found impervious to MDI (see 

API technical bulletin AX178): 

• appropriate respiratory protection. 

• chemical protective suit. 

• chemical protective gloves. 

• chemical protective boots. 





15 ____ Make sure entire unloading operation is attended as required by 49 CFR § 174.67. It is 

recommended that two operators be available. 

For Pump Unloading: 

16 ____ Make sure all rail cars valves are closed, and carefully remove the outlet cap or plugs. 

17 ____ Connect a 2-inch hose made of a material suitable for transferring MDI, such as Teflon ® 

fluorocarbon or Viton ® fluoroelastomer from the rail car unloading valve to the 2-inch fitting of the 

unloading line pump. 

18 ____ Connect the 2-inch hose from the rail car vapor exchange connection to the vapor exchange line 

from the storage tank. 

19 ____ Open the valve at the pump and the rail cars unloading valve. 

20 ____ Allow the rail tank car pad pressure and liquid head to prime the suction side of the unloading pump. 

21 ____ Open the valves on the vapor exchange line and the rail car vapor valve. 

22 ____ Start the pump and operate until the rail car is empty or receiving tank is full as indicated by the 

movement in the unloading line hose and drop in gauge pressure. 

23 ____ Turn the pump off and then close the unloading line valves. 

24 ____ Blow the lines with nitrogen or dry air and then close the vapor exchange line valves. 

25 ____ Disconnect the unloading and vapor exchange hoses, and replace the caps and plugs on 

pipelines and hoses. Use suitable tool to tighten all caps and plugs. 

26 ____ Remove personal protective equipment. 

For Pressure Unloading: 

16 ____ Make sure all rail car valves are closed and carefully remove the outlet caps or plugs. 

17 ____ Connect the stainless steel or either Teflon ® fluorocarbon or Viton ® fluoroelastomer hose to the 

unloading valve on the rail car. 

18 ____ Use a 1-inch hose to connect a supply of oil-free, dry air or nitrogen (with dew point of -40ºF) to 

the rail car air/N2 valve. 

19 ____ Pressurize railcar with 35 psi maximum nitrogen or dry air and verify that it does not leak. 

20 ____ Open the storage tank vent valve to a suitable vent gas treatment system. 


Appendix 3-3




21 ____ Open the valves in the unloading line to the storage tank. 

22 ____ Open the rail car unloading valve to start the flow of material to the bulk storage tank. 

23 ____ Leave the valves in the open position until the receiving tank is full or the rail car is empty as 

indicated by the movement in the unloading line hose and drop in gauge pressure, and 

immediately shut off the air or nitrogen supply to the rail car. 

24 ____ Ensure a positive pad pressure of at least 10-psig remains on the empty rail car. 

25 ____ Close 1" air/nitrogen valve on the car, bleed and then disconnect air/nitrogen hose from the rail car. 

26 ____ Close the valve in the receiving piping and the 2-inch unloading valve on the rail car, bleed and 

then disconnect the unloading hose. Replace all caps and plugs on pipes, hoses and rail tank car 

outlets. Use suitable tool to tighten caps and plugs. 

27 ____ Remove personal protective equipment. 

After Unloading: 

1 ____ Ensure all valves on the car are closed, all closure caps and plugs are installed, wrench tight and 

all caps and plugs are secured to the car with chains. 

2 ____ Ensure the top valve cover hatch is closed and the securement pin installed. 

3 ____ Ensure the manway bolts are secure. 

4 ____ Ensure there is no product residue on the top or sides of the car. 

5 ____ Remove chocks. 

6 ____ Remove blue flags. 

7 ____ Lower derail. 

8 ____ Confirm that all obstacles are clear of the rail tank car and that the car is ready to move. 

9 ____ Offer the car to the railroad for return shipment. 




Appendix 4: Guidelines for the Inspection of Intermodal Tank 

Containers (A Suggested Checklist) 

This appendix contains guidance for inspecting Intermodal Tank Containers (ISOTainers). Because of 

variations in the configuration of a customer’s facilities, the specific activities involved or the sequence in 

which they are conducted may differ from that described in this appendix. 

U.S. Department of Transportation regulation 49 CFR § 174.67(i) requires that throughout the entire period of 

unloading and while unloading equipment is attached, a qualified person must attend the intermodal tank 

container unloading process to ensure safety. The current DOT attendance requirements demand “physical 

on-site attendance by a person who is alert, within 25 feet and has an unobstructed view of the unloading 

operation.” 

Cargo Tanks used for the transport of MDI must meet the design and construction requirements of the US 

DOT. When MDI is shipped in a DOT specification container permitted by 49 CFR Part 173, it must conform 

to the applicable design specifications in Part 178. 


Appendix 4-1



Suggested Checklist for Intermodal Tank Container Inspection 

Pre-Loading Inspection 

Frame 

1. ____ Corner Post 

2. ____ Cross Members 

3. ____ Bottom Side Rails 

4. ____ Top Side Rails 

5. ____ Front/Rear Bottom Rail 

6. ____ Front/Rear Top Rail 

7. ____ Diagonal Brace 

8. ____ Gusset 

9. ____ Corner Protection Plate 

10. ____ Stiffener 

11. ____ Ladder 

12. ____ Walkway 

13. ____ Tank Mountings 

14. ____ Painted Surfaces 

Tank Barrel 

1. ____ Cleaned 

2. ____ Reload 

3. Last Contained ____________________________ 

Tank Barrel Accessories 

1. ____ Air Inlet Valve 

2. ____ Top Discharge Valve 

3. ____ Vapor Valve 

4. ____ Bottom Discharge Valve 

5. ____ Valves Identified 

6. ____ Blind Flanges 

7. ____ Gaskets 

8. ____ Remote Trip Cable 

9. ____ Manway 

10. ____ Pressure Indicator 

11. ____ Temperature Indicator 

12. ____ Spill Box 

13. ____ Safety Relief Valve 

14. ____ Rupture Disc 

15. ____ Both 

16. ____ Placard holders 

Cladding 

1. ____ Good Repair 

2. ____ Free of Corrosion 

3. ____ Product Spillage 

4. ____ Joints 

Markings 

1. ____ Missing 

2. ____ Legible 

3. ____ Unnecessary Markings 

4. ____ Proper Shipping Name 

5. ____ Document Holder 

6. ____ CHEMTREC Placard (800-424-9300) 

Data Plate 

1. ____ Periodic Inspection (5 yrs) 

2. ____ Visual Inspection (2.5 yrs) 

Loading Information 

1. Container Last Contained 

__________________________________________ 

2. Quantity to Load ________ 

3. Heat to While Loading ________ 




Suggested Checklist for Intermodal Tank Container Inspection 

4. Customer Temp Specs ________ 

5. Storage Tank Loaded From 

__________________________________________ 

6. Temperature of Storage Tank ________ 

7. Tank Level Before Loading ________ 

8. Tank Level After Loading ________ 

9. Time Loading Started ________ 

10. Time Completed ________ 

11. Commodity Outage (2% min) by: 

Meter ______ Scale Ticket ______ Other ______ 

12. Container Minimum 80% Full ________ 

Post Loading Inspection 

1. ____ Plant Fittings & Gauges Removed 

2. ____ All Valves Closed, Flanged, and Free 

of Leaks 

3. ____ Dome Closed and Properly Secured 

4. ____ Spill Dam Area Clean 

5. ____ Nitrogen Warning Label Affixed 

6. ____ Product Bulk Tag Affixed 

7. Container Padded to ________ lbs. 

8. Pressure Held for ________ minutes 

9. ____ Placards Affixed (all four sides) 

10. UN No. ________ 


Appendix 4-3




Note: The principal purpose of these guidelines is to provide information about the hazards, or potential hazards to 

health and safety associated with the transportation, handling, and disposal of Methylene Diphenyl Isocyanate (MDI). 

The information herein is offered in good faith and is believed to be accurate and reliable as of the date of publication; 

however, it is offered WITHOUT WARRANTY, EXPRESSED OR IMPLIED, AS TO MERCHANTABILITY, FITNESS FOR A 

PARTICULAR PURPOSE, OR ANY OTHER MATTER. 

Published by: Alliance for the Polyurethanes Industry, a business unit of the American Plastics Council 


ALLIANCE FOR THE 

POLYURETHANES 

INDUSTRY 

A BUSINESS UNIT OF THE AMERICAN PLASTICS COUNCIL 

Reference Number: AX198 

1300 WILSON BOULEVARD, SUITE 800 

ARLINGTON, VA 22209 

703.253.0656 FAX 703.253.0658 

www.polyurethane.org www.plastics.org

MDI Transportation Guidelines - Polyurethanes - American ...

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