Workers unclogged a backed-up line early Wednesday afternoon and stopped an ammonia leak at the PCS Nitrogen complex in Geismar, LA, that forced the closure of a state highway for nearly eight hours, state officials said.
Once workers cleared the blockage, pressure in the line, which ties into an ammonia storage tank, reduced and a pressure relief valve closed, halting the flow of the noxious gas to the atmosphere, state environmental and police officials said.
Garry Hiebert, human resources manager for PCS Nitrogen, said there were no injuries on- or off-site. He said company engineers are trying to calculate how much ammonia escaped and are investigating the root cause of the leak.
Parts of LA 3115 between LA 30 and LA 75 (Saint Gabriel) ended up closed as a precaution near the plant in Ascension Parish, said Louisiana State Police officials.
The State Police and the state Department of Environmental Quality representatives remained at PCS Nitrogen Wednesday afternoon.
“We are still in place to monitor and assess the event,” said Greg Langley, DEQ spokesman.
Langley said Wednesday afternoon the last air tests taken in the area detected no ammonia.
Air readings taken from La. 3115 early Wednesday showed elevated amounts of ammonia gas, Langley said. But he could not say how high those levels were.
He said calculations for how much ammonia released were still in the works Wednesday afternoon.
Hiebert said workers spotted the leak from the storage tank in the plant’s ammonia production unit about 4 a.m. and notified authorities.
Ammonia, which has a pungent odor even at low concentrations, immediately burns the nose, throat and respiratory tract at higher concentrations.
Even at low concentrations, ammonia, one of the most widely produced industrial chemicals commonly used in the fertilizer industry, can cause coughing and irritate the nose and throat.
The PCS Nitrogen Fertilizer LP plant is a subsidiary of Potash Corp., a Saskatoon, Saskatchewan, Canada-based company that mines large deposits of potash across Canada but also produces ammonia and phosphate. All three end up used in agricultural production.
The Geismar plant, which is one of Potash’s four nitrogen complexes worldwide, produces 500,000 tons of ammonia per year in addition to urea, nitrogen solutions, nitric acid and ammonium nitrate, according to the company website.
PCS Nitrogen opened its once-shuttered ammonia unit in Geismar in 2011 to take advantage of low natural gas prices from the U.S. shale gas boom. The company invested $158 million to restart the unit, which closed in 2003 because of high natural gas prices at the time.