This testimony presents the views of NIOSH regarding worker exposure to 1,3-butadiene (106990). Approximately 65,000 workers are potentially exposed to 1,3-butadiene. Health hazard evaluations have been made at companies which produce helmets and visors, synthetic rubber, rubber tires and tubes, automotive weather stripping, braided hoses, and plastic components for aircraft. From these studies worker exposures were seen to range from 0.06 to 39 parts per million (ppm) as an 8 hour time weighted average. A study has also been ongoing of the monomer producing and polymer producing industries to determine the extent of exposure to workers in these industries to 1,3-butadiene. In these factories, exposures ranged from 1 to 370ppm with an average of less than 10ppm. The surveys have indicated that engineering controls and work practices can effectively reduce worker exposures to 1,3-butadiene. Closed loop sampling systems can effectively reduce worker exposure and the use of magnetic gauges in lieu of slip tubes to monitor the filling of containers for shipment has reduced exposures.