Exclusions for Massive Forms of Certain Metals

EPA allows a reporting exception for massive forms of certain solid metals (antimony, arsenic, beryllium, cadmium, chromium, copper, lead, nickel, selenium, silver, thallium, and zinc) when the diameter of the released metal equals or exceeds 100 micrometers (0.004 inches). The Agency set the cutoff size 10 times larger than the maximum size considered by EPA to be respirable dust to ensure that the government would be notified of releases containing small, inhalable particles of metals.