Lottia digitalis lobed and irregular. The shell characteristics are very variable. The color is usually brown or dark olive with white patches. The range of "L. digitalis" extends from northern Alaska to northern Mexico. It is a common species and is found among acorn barnacles on vertical rock faces in high to mid-intertidal zones, on both exposed and sheltered coasts. In California, young limpets, up to ten millimetres in diameter, often live on the opercular plates of gooseneck barnacles, "Pollicipes polymerus" and on mussel shells. In both cases, the colouring varies from that of the rock-based form and provides camouflage. At Mission
Radioactive contamination from the Rocky Flats Plant tests." As noted by Carl Johnson in Ambio, "Exposures of a large population in the Denver area to plutonium and other radionuclides in the exhaust plumes from the plant date back to 1953." Weapons production at the plant was halted after a combined FBI and EPA raid in 1989 and years of protests. The plant has since been shut down, with its buildings demolished and completely removed from the site. The Rocky Flats Plant was declared a Superfund site in 1989 and began its transformation to a cleanup site in February 1992. Removal of the plant and surface contamination was