A state environmental crew today was seeking to determine what caused more than 250 gallons of liquid ammonia to leak from a Laurel ice cream factory last night, causing the evacuation of 15 workers and about 60 residents of a nearby trailer park.
Workers at the East Coast Ice Cream Novelties plant at 9090 Whiskey Bottom Road near U.S. 1 were evacuated when the leak began about 8:44 p.m., said Battalion Chief Donald R. Howell of the Howard County Fire Department.
The plant makes ice cream products for High's convenience stores.
Four workers, a firefighter and one other person were treated for mild inhalation of ammonia fumes, Chief Howell said.
Company officials refused last night to comment on the leak.
But Chief Howell said the ammonia leaked from a broken pipe in a 3,000-pound tank.
Members of the county fire department's hazardous materials team stopped the flow of ammonia and cleaned up the spill.
"We understand several hundred gallons of ammonia, which is used as a refrigerant at the plant, did escape from a fractured pipe," Chief Howell said.
The ammonia caused a vapor cloud to form over the area. The cloud drifted a quarter-mile from the plant, shifting directions with the wind and passing over a nearby mobile home park, fire officials said.
About 9 p.m., 50 to 60 residents of the nearby Pfister Trailer Park were evacuated from their trailers as a precaution. They gathered outside the California Inn up a hill from the plant, fire officials said.
Thirty-one pieces of fire department equipment and more than 60 fire and rescue personnel responded to the emergency.
"The biggest thing was how we'd stop the leak and dissipate the cloud," said Battalion Chief Richard Freas.
Members of the hazardous materials team stopped the flow of ammonia shortly after 10 p.m. and used water to dilute the ammonia and fans to ventilate the building.
"The winds took care of the rest," Chief Freas said. He said that because the water diluted the ammonia before it could get into nearby streams, there was no health risk.
"It's not an environmental problem once the dilution occurs," Chief Freas said.
Residents of the trailer park were allowed to return to their homes shortly after 10:30 p.m.
L Chief Freas said the leak could have caused a major problem.
To illustrate the potential severity, he said a container of household ammonia, which is diluted with water, is almost unbearable if inhaled. "This is 100 percent," he said of the ammonia that leaked. "So you can imagine . . . it's some potent stuff."
The Associated Press contributed to this story.