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Ammonia spill on trawler in Dutch Harbor sends 2 to hospital

Laurel Andrews

Two workers were hospitalized and at least 120 people were evacuated from a factory fish- processing ship that leaked up to 5,000 pounds of anhydrous ammonia in port at Dutch Harbor Saturday afternoon.

The two were flown to Anchorage for medical treatment. The ship, the 367-foot-long M/V Excellence, was relocated to a moorage in Wide Bay, about 7.5 miles from the Kloosterboer North Dock in Dutch Harbor, where it leaked. Workers cannot enter the engineering space where the ammonia is leaking because of the danger, said Steven Russel of the Alaska Department of Environmental Conservation. 

Anhydrous ammonia is used as a coolant in the vessel's refrigeration system. When compressed, the ammonia is a liquid, but upon release it turns into a gas. The gas displaces the oxygen in the body, causing nausea, shortness of breath, irritation to the eyes and headaches.

Ammonia is leaking at a fairly low pressure of less than 4 pounds per square inch. Russell said up to 4,000 pounds of the 22,000 pounds of ammonia aboard the vessel has been released. But Russel did not anticipate much more leakage due to the leak's location in the refrigeration system.

Once the leak was detected, nearby areas were cleared and the workers were evacuated. One of the workers flown to Anchorage has been released from the hospital.

The Unalaska fire department has been combating ammonia vapors from the vessel using a high-pressure water fog. DEC plans to monitor the vessel until it's safe for Hazmat teams to board and gather air data. Select members of the crew with Hazmat training are working alongside the Unalaska Fire Department and the U.S. Coast Guard.

The M/V Excellence was built as a factory trawler in 1973 and refitted in 1990 for use as a factory processor.