CHARLESTON, W.Va. -- About 20 pounds of ammonia was released early Tuesday when a relief valve opened on the top of the huge ammonia tank at DuPont Co.'s Belle plant.
No one was injured in the incident.
DuPont spokesman David Hastings said the incident occurred at about 2:30 a.m. and the all-clear was sounded shortly after 3:10 a.m.
Hastings said a remote sensor on top of the tank detected the leak, which came from a vent intended to open and relieve pressure inside the vessel. It was not clear what caused the vent to open this morning.
"We have an investigation underway now to try to get at the cause of the leak," Hastings said.
Initial reports on the size of the leak put it well under the 100-pound amount that would require an official report to emergency responders and environmental regulators.
The huge white ammonia tank with the DuPont logo towers over the rest of the Belle facility.
The tank has a total capacity of 40 million pounds, but for years DuPont has never kept it more than half full. Hastings said the tank contained about 10 million pounds of ammonia at the time of Tuesday morning's incident.