Health hazard evaluation report: HETA-2007-0199-3075, evaluation of employees' exposures to welding fumes and powder paint dust during metal furniture manufacturing, Dehler Manufacturing, Inc., Chicago, Illinois.
On April 6, 2007, NIOSH received a confidential employee request for an HHE at Dehler Manufacturing, Inc., (Dehler) in Chicago, Illinois. Employees were concerned about exposure to welding fumes and dust from powder painting and grinding operations. During our initial site visit on June 28-29, 2007, we met with management and employee representatives; toured the facility; observed work processes, use of PPE, and existing engineering controls; and interviewed 10 employees. We collected bulk samples of powder paint for particle sizing and to check for silica and asbestos content. Two of the 10 employees we interviewed reported symptoms we determined were not related to exposures in the workplace. They described episodic transient shortness of breath that lasted a few minutes and also affected members of their families who were not Dehler employees. Their condition did not improve when they were away from work. Two other employees reported eye and throat irritation. The remaining six employees reported no symptoms. Although the bulk powder paint samples did not contain silica or asbestos, we decided a return survey was needed to evaluate exposures to welding fumes, powder paint, noise, and heat stress. During the follow-up evaluation on September 18-20, 2007, we collected PBZ air samples for carbon monoxide and nitrogen dioxide on welders, and for elements (metals) on welders and grinders. We also collected PBZ samples for carbon monoxide on two grinders. For the painters, we collected PBZ air samples for TGIC, respirable dust, and total dust. We measured the face velocity on door openings to the paint booth, the capture velocity on a welding fume extractor, and noise levels throughout the facility. We also evaluated heat stress in the paint room. We interviewed the nine painters who were available and provided them with self-recording PEF meters. We were interested in knowing if the painters' breathing was affected by TGIC in powder paint. These meters provide an indication of airway obstruction. Of the 38 PBZ samples for elements collected on MIG welders, seven exceeded the ACGIH TLV of 200 microg/m3 for manganese, and an additional eight samples were at least at half of the TLV. Concentrations of the remaining elements in the welding fumes were below applicable OELs. Of the 16 PBZ air samples for carbon monoxide collected on welders, four exceeded the NIOSH ceiling limit of 200 ppm. Despite painting for only 80 to 300 minutes, four of eight painters were exposed to TGIC above the ACGIH 8-hour TLV-TWA of 0.05 mg/m3. One painter's exposure to TGIC exceeded the protection factor of the filtering facepiece respirator he was wearing. Had employees applied paint containing TGIC for 8 hours or longer at the same application rate (as is commonly done for a larger work order), at least six of the eight painters would have been overexposed to TGIC. Two of 15 PBZ air samples for respirable dust collected on painters exceeded the OSHA 8-hour PEL-TWA of 5 mg/m3, and 7 of 13 PBZ air samples for total dust exceeded the OSHA 8-hour PEL-TWA of 15 mg/m3. Talc was not detected in the respirable dust air samples collected on painters. The WBGT in the paint room did not exceed NIOSH recommended heat stress exposure limits, but at times the dry bulb temperature in the paint room exceeded 100°F. On the day of our evaluation, the outdoor temperature was 77°F, so it is possible that on warmer days the NIOSH RELs may be exceeded because the production area is not air-conditioned. Noise levels exceeded 85 dBA during grinding, welding, and painting, and at most presses occasionally exceeded 90 dBA. Hearing protection was required in the press area, but some employees were observed not wearing it, or wearing ear plugs that were not properly inserted. Two of the nine painters interviewed had PEF readings with a variability of 20% or more, which may suggest asthma. One of the two painters reported having symptoms of shortness of breath, which predated employment at Dehler, and had reportedly not worsened since employment. Because these employees only had Sundays off during the period of the PEF recordings, we are unable to determine if the PEF rates would have improved while away from work. A single day away from work is not sufficient to observe such changes if present. We are therefore unable to make a determination on work-relatedness of this finding. Our evaluation did not identify any painter who had definitive work-related respiratory disease or symptoms. However, we recommended to the two painters with increased variability of their daily peak flow readings that they consult their physician for further evaluation to determine if their bronchial hyperresponsiveness was related to workplace exposures. We also recommend that management take steps to prevent employee sensitization to TGIC. We recommend using powder paints that do not contain TGIC and welding wire that does not contain manganese. The paint booth should be further enclosed to better contain the powder paint, and the painters should be provided with a higher level of respiratory protection until exposures can be reduced through engineering or administrative controls. Painters should avoid skin contact with powder paint that contains TGIC because it is also a skin sensitizer and can cause allergic contact dermatitis and asthma. Management should inform employees about the risks of working with TGIC. We recommend installing spot cooling fans and exhaust fans in the paint booth room to control heat stress, and exhaust fans in the welding area to remove welding fumes. We recommend that management conduct noise monitoring to determine employees' full-shift TWA noise exposures, and ensure employees wear hearing protection properly while in designated hazardous noise areas. We also recommend that an ergonomics consultant be hired to assess work tasks and provide recommendations for reducing the number of ergonomic injuries.