RCRA metals are hazardous metals that are monitored and regulated as a result of the Resource Conservation and Recovery Act of 1976. There are eight metals in all, including arsenic, barium, cadmium, chromium, lead, mercury, selenium and silver.
The eight metals monitored are all hazardous to human health in large quantities, though some, including arsenic and chromium, are commonly ingested by humans or vital to human health in small quantities. The largest sources of most of these metals are heavy industry, especially mining and oil drilling and refining. The RCRA also mandates monitoring of many non-metal substances because they are dangerously toxic, combustible, corrosive or reactive.