Officials at Contra Costa Health Services advised anyone Friday evening who is near the Crockett Wastewater Treatment Plant to "take steps to stay safe" due to elevated levels of hydrogen sulfide in the air.
County health officials said air monitoring conducted near the Dowrello Road plant by the Bay Area Air Quality Management District Friday afternoon detected concentrations of the gas in levels high enough to affect the health of people exposed to it for long periods of time, including symptoms such as headaches, nausea and irritated eyes.
The presence of the gas is related to an ongoing operational issue at the plant which has led to several recent complaints about strong odors in the community. Air quality officials are investigating.
Friday was the first day that detected levels of hydrogen sulfide were high enough to cause a public health concern, according to county health officials.
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Hydrogen sulfide commonly smells like rotten eggs, and health officials added that just smelling it is not necessarily an indicator that levels of the chemical in the air are high enough to pose a risk to health.
Hydrogen sulfide can be smelled at much lower levels. Concentration of the gas in the air may be higher during the afternoon, the warmest time of day.
People near the Crockett plant who are experiencing symptoms should consider leaving the area, if possible, or refrain from going outside and closing all windows and doors. Anyone with serious symptoms should contact their healthcare provider.
Contra Costa Health Services is monitoring the air daily and will post updates at cchealth.org.