Emergency Response: Toxicology and Risk Assessment
Shortly after 6:30 p.m. on August 6, 2012, hazardous materials responders and firefighters were called to a fire at the Chevron Refinery in Richmond, California. A shelter-in-place order was quickly issued for surrounding communities and residents, warning them not to breathe the smoke. During the fire, 17 direct readings of air were taken onsite by refinery personnel. All readings were below the limit of detection (0.1 ppm) for hydrogen sulfide (H2S) and sulfur dioxide (SO2). Refinery personnel collected 19 grab samples of air downwind of the fire and analyzed them for sulfur compounds and hydrocarbons. All concentrations were below the reference exposure levels (RELs) established by the Office of Environmental Health Hazard Assessment (OEHHA). Continuous fenceline monitoring showed slightly elevated concentrations of H2S (0.003-0.005 ppm) and SO2 (0.002-0.007 ppm); however, these levels were below the OEHHA acute RELs. Local environmental health and air quality agencies coordinated to collect
additional community air samples during the fire. Air grab samples were analyzed for toxic air contaminants. Some 20 volatile chemicals were detected at concentrations above background but at levels below those associated with adverse health effects. The exception was one sample that contained 3.23 ppb (7.41 µg/m3) acrolein, well above the OEHHA acute REL of 2.5 µg/m3. Concentrations of particulate matter from the smoke were below both state and federal air quality standards, although marginally higher when compared to typical levels for that time of year. With the exception of acrolein, no toxic air contaminants were detected at levels associated with adverse health effects, and particulate matter levels were near normal. Even so, on the day of the fire over 360 patients were seen in area emergency departments and one adult and two children were hospitalized. By 17 days later, over 15,000 individuals had sought care, mostly for minor nose, throat, or eye irritation or respiratory effects [1-8].