What is arsenic, and why would it be present at the RFS?
Arsenic is a naturally occurring element present in Bay Area soils in concentrations of 5 to 20 mg/kg (parts per million). As such, it is expected that soil and dust samples will contain some background levels of arsenic. Ambient air is also expected to contain arsenic in background concentrations ranging from 0.04 to 1.0 µg/m3. According to the U.S. Department of Labor Occupational Safety and Health Organization (OSHA), the permissible occupational exposure limit to arsenic is 10 µg/m3. Impacts on human health can be seen with exposure to (ingestion, inhalation and skin contact) elevated levels of arsenic, which can occur in areas with significant arsenic pollution or abnormally high natural soil or water concentrations of arsenic. Arsenic is also found as a naturally occurring constituent of iron sulfide ore (pyrite), which was used for manufacturing sulfuric acid at the former Stauffer Chemical Company, a property now owned by Zeneca, a private development not associated with UC Ber
