One of two metal processing firms air regulators blame for elevated levels of hexavalent chromium in Paramount has reached an agreement over how to curb its emissions. The South Coast Air Quality Management District is still in negotiations with the other firm, according to an agency spokesman.
Aerocraft Heat Treating Co. has agreed to stop any operations involving chromium if the average of results from the three most recent air monitor samples shows hexavalent chromium emissions exceeding 1 nanogram per cubic meter. This threshold is designed to greatly reduce the cancer risk of nearby residents in the south Los Angeles city, according to air district spokesman Sam Atwood.
The district’s independent Hearing Board must approve the plan before it takes effect. The board began taking public testimony Wednesday in Diamond Bar; it will continue on Thursday.
If the board signs off on the deal, Aerocraft must also stop chromium operations in the first seven days that the agreement is in effect if any single air monitoring sample has a reading of more than 3.3 nanograms per cubic meter.
The plan says if the air district determines the company has exceeded the threshold, it will have until midnight of the day it is notified to stop operations that emit the carcinogen. The order would be in effect until the end of 2018.
The accord will be "extremely challenging to the company, but ultimately something that's in the best interests of the community, of the company, of the air district," said Tom Wood, an attorney representing Aerocraft. "It is a responsible way for all of us to move forward."
Air district lawyer William Wong asked the Hearing Board for an "expeditious approval" of the abatement plan. "We don’t feel there’s the need for testimony to establish any [public nuisance] or anything like that," he said.
Anaplex Corp., the second Paramount metal processor accused of emitting too much hexavalent chromium, has not yet reached an agreement with the AQMD. Anaplex is still in negotiations with district staff, according to an agency spokesman, who expressed hope the company will sign on to the same plan as Aerocraft.
Earlier in the week, Anaplex requested the Hearing Board postpone its session for at least 30 days. It said there is inconclusive evidence that the company is a major source of hexavalent chromium in Paramount, and objected to its case being linked to that of Aerocraft.
At the meeting Wednesday, the Board agreed to separate the two company's cases and Anaplex agreed to set its motion aside.
The AQMD asked the Hearing Board to force Aerocraft and Anaplex to correct the hexavalent chromium problem in Paramount after air monitoring earlier this fall found emissions 350 times typical background levels, according to the air district.
The air district claims that there are other firms in the city emitting dangerously high levels of hexavalent chromium, also known as chromium 6.
The AQMD defines an "acceptable" cancer risk level as 25 in a million, and a risk of 100 in a million or higher as a "significant" risk level.
The agency started monitoring the air in Paramount in 2013, after community members complained about metallic odors.
Residents believed the source of the odors was Carleton Forge Works. Since then, Carleton Forge voluntarily implemented new measures to reduce emissions and odors. The district said the changes reduced the levels of nickel in the air.
But monitoring shows that chromium 6 levels have been increasing over the past year. The AQMD deployed eight additional monitors in Paramount in mid-October; they first registered the extremely high chromium 6 levels on Oct. 27.