Control of air contaminants at mixers and mills used in tire manufacturing.

The National Institute for Occupational Safety and Health (NIOSH) has completed an evaluation of control techniques for airborne vapors and particulates in tire manufacturing. As part of this evaluation, Banbury mixers and mills were studied. This equipment is used to mix elastomers, carbon black, oil and other ingredients into a homogeneous mixture. These mixing and milling operations normally generate aerosols. Control of these air contaminants may be accomplished by using the following: local exhaust ventilation, equipment configuration and material substitution. Results of personal sampling for total aerosols at Banbury mixers showed the geometric means of mixer operators' exposures at five plants ranged from 0.08 to 1.54 mg/m3. Similar sampling at three plants for milling operations showed the geometric means of milling operators' exposures ranged from 0.20 to 1.22 mg/m3.