Arsenic is a silver-gray brittle, crystalline solid. It exists also in black and yellow amorphous forms. It is used as an alloying agent for heavy metals and also in special solders. Many scientists believe there is no safe level of exposure.
Some people develop white lines on the nails.
Repeated exposure can also cause liver damage, narrowing of the blood vessels, or interfere with the bone marrow's ability to make red blood cells. Post hazard and warning information in the work area.