Perchlorate is both naturally occurring and man-made. In its natural form, perchlorate is a contaminent in fertilizers. Man-made perchlorate is used in a wide variety of industrial applications including the production of rubber and paint, in lubricants, and as a primary ingredient in solid rocket propellant. Perchlorate is highly water soluble and can migrate into groundwater and surface water, posing a concern to drinking water supplies. Thirty-five states have detected perchlorate in drinking water at higher levels than expected. The United States Environmental Protection Agency (US EPA) has established an official reference dose of 0.0007 ppb per day of perchlorate. Maryland, Massachusetts and New Mexico have established a one part per billion (ppb) action limit, while California and Texas have established 4 ppb limits.