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 of substantial contamination from the 1957 plutonium fire until after the highly visible 1969 fire, when civilian monitoring teams confronted government officials with measurements made outside the plant of radioactive contamination suspected to be from the 1969 fire, which consumed hundreds of pounds of plutonium (850 kg). The 1969 fire raised public awareness of potential hazards posed by the plant and led to years of increasing citizen protests and demands for plant closure. Releases from previous years had not been reported publicly prior to the fire; airborne-become-groundborne radioactive contamination extending well beyond the Rocky Flats plant was not publicly reported