Specifications include, but are not limited to: The liquid chlorine supplied shall be not less than 99.5 percent pure by volume. • The liquid chlorine supplied shall be dry chlorine. Moisture shall not exceed 150 ppm (0.015 percent) by weight. • The sum of all heavy metals shall not exceed 30 ppm (0.003 percent) expressed as lead. • Lead shall not exceed 10 ppm (0.001 percent) reported as lead. • Mercury shall not exceed 1 ppm (0.0001 percent) reported as mercury. • Arsenic shall not exceed 3 ppm (0.0003 percent) reported as metallic arsenic. • Total nonvolatile residue shall not exceed 50 ppm (0.005 percent), by weight, in liquid chlorine, as loaded by the manufacturer in tank cars and chlorine tank trucks. • Carbon tetrachloride shall not exceed 100 ppm (0.010 percent). Testing for carbon tetrachloride is not required unless a carbon tetrachloride tail-gas scrubbing system is used in the chlorine production unit. • Trihalomethanes shall not exceed 300 ppm (0.030 percent)