In 2006, the U.S. Occupational Safety and Health Administration (OSHA) dropped the permissible exposure limit (PEL) for hexavalent chromium from 52 to 5 micrograms per cubic meter, due to its known health impacts on workers exposed to high amounts. Employers were required to inform workers only when hexavalent chromium was greater than the PEL. Ralph Nader’s Public Citizen Group challenged the rule, arguing that employers should inform workers if they are exposed to any hex-chrome. OSHA agreed, since the hex-chrome regulation is consistent with other substance-specific health standards, such as those for lead and arsenic.