Motorola, Siemens and GlaxoSmithKline will collectively pay a $500,000 civil penalty for system failures that led to the release of trichloroethylene into the Scottsdale, Ariz., public drinking water system, the Department of Justice and Environmental Protection Agency said Monday.

Trichloroethylene (TCE) is an industrial solvent known to cause cancer as well as liver and kidney problems. When inhaled, trichloroethylene causes headache, dizziness, and confusion. Increasing exposure may lead to unconsciousness or death.

TCE is one of the most frequently detected contaminants in groundwater in the U.S., appearing in up to 34 percent of tested U.S. drinking water supplies although rarely does it exceed levels the EPA deems safe for drinking.