Natural Resource Damage Assessment: Methods and Cases

D. M/V Formosa Six
Location: The site is in the Gulf of Mexico, about three miles off the Southwestern pass
of the Mississippi River. On April 11, 1997, the M/V Formosa Six, a chemical tanker, collided
with the M/V Flora, causing a large chemical release from the M/V Formosa Six into the water.
Release: 1,500 to 1,800 metric tons of ethylene dichloride (EDC) were released from the
M/V Formosa Six into the Gulf waters.
Injury: Because EDC has a much higher specific gravity than sea water, the trustees
estimated that most of the EDC sank rapidly to the sea floor below, with minimal exposure to
marine animals on the surface or in the water column. Sampling of the sea floor, done in May
1997, revealed that EDC was present in the sea bed at a concentration of greater than 100 parts
per million (ppm) over a 12 acre area. The highest concentration found was greater than 26,000
ppm. Approximately 50 acres showed concentrations between one and 100 ppm. EDC
biodegrades slowly, and was expected to gradually disperse into the water column. Dispersion
occurs more rapidly when the water is turbulent. Hurricane Daniel passed near the area in July of
1997. Based on these facts, the trustees believed that by May 1999, the affected area had
recovered completely.
Although the accident caused vessel traffic to be rerouted, any effect on commercial or
recreational use of the area was negligible. The only significant loss of resources was the effect
on services provided by benthic bacteria on the sea floor. Benthic bacteria breaks down organic
matter that settles on the sea floor, and they serve as prey for larger organisms, including the
commercially important brown shrimp. Concentrations of EDC over 100 ppm occurred over an
area of 12 acres, and are estimated to have caused a loss of services from benthic organisms for
approximately two years.
Attachment of Liability: NRDs are permitted under both CERCLA and CWA because
of the “release” or “discharge” of a hazardous substance into the waters of the adjoining
shorelines of the United States or into a contiguous zone of the United States.
Trustees:
• National Oceanic and Atmospheric Administration
• Louisiana Department of Wildlife and Fisheries
• Louisiana Department of Environmental Quality
• Louisiana Department of Natural Resources
Potentially Responsible Parties:
• Formosa Plastics Tanker Corporation, owner and operator of the M/V Formosa Six at
the time of the incident.
• EFNAV Co., LTD, manager of the M/V Flora at the time of the incident.
• Segesta Shipping Co., LTD, owner of the M/V Flora at the time of the incident.
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