 The 8 hour time weighted average ( TWA ) is set at 0 @.@ 5 mg / m3 by the American Conference of Governmental Industrial Hygienists and by the Occupational Safety and Health Administration ( OSHA ) as a legal permissible exposure limit ( PEL ) in the workplace . The National Institute for Occupational Safety and Health ( NIOSH ) has set a recommended exposure limit ( REL ) of 0 @.@ 5 mg / m3 as an 8 hour TWA . Antimony compounds are used as catalysts for polyethylene terephthalate ( PET ) production . Some studies report minor antimony leaching from PET bottles into liquids , but levels are below drinking water guidelines . Antimony concentrations in fruit juice concentrates were somewhat higher ( up to 44 @.@ 7 µg / L of antimony ) , but juices do not fall under the drinking water regulations . The drinking water guidelines are : 
