The Los Angeles-based group Environment California says an industry-funded group is using "misleading research and tobacco industry-style lobbying to influence the debate on the effects of perchorate." Perchlorate is a rocket fuel ingredient and "a known thyroid inhibitor" often present in water supplies near military and manufacturing sites. The Perchlorate Study Group (PSG) "has lobbied for maximum contaminant levels of 200 parts per billion (ppb) in drinking water, much higher than the 24.5 ppb threshold favored by the Environmental Protection Agency and the 6 ppb limit being considered by the state of California," reports Fred Ortega. "More than half of all studies on the health effects of perchlorate published between 1995 and 2005 were funded by" PSG, which was founded by Lockheed Martin, Aerojet and Kerr McGee, "in response to efforts to regulate the potentially dangerous chemical." Environment California also notes that PSG retained the PR firm APCO Worldwide, which previously helped "Phillip Morris to fight anti-tobacco regulations," to "help undermine the case for thorough perchlorate cleanup."