Marsh Fire in East Contra Costa still smoldering, spreading smoke 6 weeks later

PITTSBURG -- Why the Marsh Fire in East Contra Costa County is still burning after six weeks is chiefly because of its fuel: peat, which isn't easy to put out once it ignites.

The smoldering fire prompted the Bay Area Air Quality Management District to issue an air quality advisory for wildfire smoke in eastern Contra Costa County for Tuesday and Wednesday. Smoke is expected to impact Pittsburgh, Antioch, Oakley and Brentwood.

Contra Costa Health Services also issued an advisory for Pittsburg residents to stay inside with windows and doors closed and limit outdoor activity.

Daytime onshore winds will likely disperse smoke, but as winds die down overnight, localized pollution levels may rise between 10 p.m. and 9 a.m. Pollutant levels are not expected to exceed the national 24-hour health standard.

The peat that's burning is spongy material formed by the partial decomposition of organic matter, usually plant material found in wetlands.

"Peat fires are very difficult, almost impossible, to extinguish," said Steve Hill, spokesperson for the Contra Costa County Fire Protection District.

Much of the fire has burned in areas accessible only by foot, which also works against firefighters. The intermittent smoke it produces depends on the weather.

The fire started in a homeless encampment near Solano and Suisun avenues in Bay Point on May 28, burning about 200 acres before firefighters got it under control. High winds flared the fire back up Saturday, causing it to burn into Pittsburg, threatening PG&E lines and getting close to homes.

Firefighters from the county fire district and Cal Fire stopped its forward progress with a heavy aerial attack Saturday. The fire has burned about 500 acres, about 75 of which burned Saturday.

The fire smoldered Monday until Tuesday, with firefighters monitoring the area in case it flares up again. There was enough smoke still in the area Monday to prompt Contra Costa Health Services to advise Pittsburg residents to stay indoors with windows and doors closed and to limit outdoor activity due to poor air quality in the area.

Con Fire officials say the fire is nearly out of fuel and, though still smoldering, shouldn't be a danger to people or structures.