MARTINEZ, Calif. (KRON) — A refining company in Martinez is facing another slew of complaints after their second plant incident in two months. On Saturday, the Bay Area Air Quality Management District released their report on the flaring observed on Friday.

At 4:45 p.m. on Friday, staff with the Air District saw a plume of black smoke in the sky above Martinez. Staff traced the plume back to the flare that occurred at the Martinez Refining Company (MRC).

At 5 p.m., MRC put out a statement on the company’s Facebook page which said the refinery was experiencing a an equipment issue that caused “intermittent flaring.” A representative with MRC later told the Air District that a “critical piece of equipment unexpectedly tripped offline.

This failure caused gases to be routed up to the “LOP flare,” and the flaring resulted in a reportable quantity of sulphur dioxide. Air District staff reported that the flaring they could observe stopped by 5:44 p.m.

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Air District staff members received 21 complaints from residents in Martinez who reported black smoke and flaring in the area. Staff members also determined that at the time the flaring occurred, the wind was blowing in a southwest direction between 1-2 mile per hour.

MRC shared ground level monitoring data with Air District staff, and the staff members report that no exceedances were observed. Members of the Contra Costa County Hazardous Materials team were also onsite to collect air samples for further analysis.

The Air District says it will continue to investigate the flaring incident at MRC. At this time, no Notices of Violation have been issued, but the Air District anticipates that it may find regulatory violations as it investigates.

The flaring at MRC took place only about two weeks after Martinez residents reported a white powder had settled over the area after an incident at MRC. The Contra Costa County Health Department held a press conference on the expulsion of the powder, and officials reported that testing of the materials found heavy metals in the powder. DPH officials say that MRC did not inform them of this incident in a timely manner, and the company could face penalties for the delay.