Contra Costa Health (CCH) lifted a health advisory in Crockett after air readings taken during the previous two days no longer detected hydrogen sulfide in the air coming from the Crockett Wastewater Treatment Plant, Contra Costa Health Services said.
Though the advisory has been lifted, officials will still be monitoring the area.
One-hour average readings at three Crockett locations came back negative for hydrogen sulfide– John Swett High School, Carquinez Middle School and at Port and Ceres streets.
The hydrogen sulfide emission was due to a weeks-long issue at the treatment plant, which is owned by the C&H Sugar refinery and operated via contractor Inframark.
The advisory first went out on Oct. 7. Workers at the plant have cleaned more than 1,300 air diffusers in the plant’s three wastewater treatment reactors throughout the week in an effort to reduce emissions of the chemical.
Contra Costa Health Services initially issued a health advisory for Crockett residents after air monitoring by the Bay Area Air Quality Management District found a one-hour average level of hydrogen sulfide of .036 parts per million.
According to CCHS, symptoms of hydrogen sulfide exposure, including headaches, nausea and eye irritation may begin to show at .03 ppm.
