Guidelines for care & Use of Dry Solvent Stills [Example]

4. INTERPRETING CHEMICAL HAZARD HMIS RATINGS
The HMIS (Hazardous Material Information System) rating consists of a set of three numbers
representing Acute (or immediate) Toxicity, Fire, and Reactivity, in that order, followed by a letter code for
Personal Protection Equipment and ending with a letter(s) for Chronic (or long-term) Toxicity, if necessary.
The numerical hazard ratings are as follows:
4 - severe hazard Chemical Inventory Safety Data Column Key
3 - serious hazard ct = Chronic toxicity hazard, if indicated by an asterisk
2 - moderate hazard at = Acute Toxicity fl = Flammability
1 - slight hazard re = Reactivity pe = personal protective equipment
0 - minimal hazard ct2 = actual description of Chronic toxicity hazard
The Personal Protection Equipment code (PPE) begins with letter A for least equipment needed
(safety glasses), through H (the most common – standing for use of safety glasses, lab coat, gloves, and a
hood) and ends with K for something extremely dangerous and requiring elaborate protection, such as selfcontained
breathing apparatus. Note that a good fume hood may normally be used in place of respirators.
An asterisk next to the Acute Toxicity rating in the first column on the left indicates that a special
“Chronic”, or long-term, hazard exists for the chemical, and will be identified by an additional letter(s)
immediately following the capitol letter designation for PPE in the last column on the right. In some cases,
a chemical could have more than one chronic health hazard letter designation. These special hazards are:
M –mutagen Example: for Benzene, *330Hcm
m - suspected mutagen Acute toxicity is 3, with an associated Chronic hazard
T – teratogen Flammability rating is 3
t - suspected teratogen Reactivity rating is 0
C – carcinogen PPE rating is H
c - suspected carcinogen Chronic toxicity rating is cm
A – allergen (for suspected carcinogen and
S - can cause silicosis suspected mutagen)
Note that chronic health hazards may also be indicated in plain English on the container
label and/or the MSDS sheet. Chemicals bought from a company and sent without MSDS sheets must be
assumed to have ratings in each category of 4 until proven otherwise. Missing hazard data in any category
of an MSDS sheet will likewise result in a rating of 4 unless the faculty or the laboratory manager judges
the chemical deserving of a lower rating based on knowledge of chemical properties.
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