(OSHA FactSheet) Controlling Exposure to Hexavalent Chromium in Aerospace and Air Transport Painting
Hexavalent chromium or Cr(VI) is a toxic form of chromium which can cause severe health effects to workers, including lung cancer. Chromium compounds are added to paints and primers to provide corrosion protection and to create specific colors.
Painting operations in the aerospace and air transportation industries can expose workers to hazardous levels of Cr(VI).
The OSHA Permissible Exposure Limit (PEL) for worker exposure to Cr(VI) is 5 µg/m3 [as an 8-hour-time weighted average (TWA)] and OSHA regulates worker exposure to this hazardous substance under its Chromium (VI) standard, 29 CFR 1910.1026.
Painting operations that expose workers to hexavalent
chromium Certain paints and primers may contain Cr(VI), a cancer-causing compound regulated by OSHA. Exposure to Cr(VI) can occur during the painting of aircraft exteriors, interiors or parts, and during the removal of chromate-based coatings. Job tasks that may expose workers to Cr(VI) include spray painting, sanding, grinding and abrasive blasting.
Health effects of exposure to Cr(VI)
• Lung cancer and nasal and sinus cancer
• Eye, nose and throat irritation
• Nasal septum ulcerations and perforations, gastritis, and gastrointestinal ulcers
• Contact dermatitis, irritation, ulcers, and sensitization from skin contact
Methods to reduce Cr(VI) exposure levels when spray painting aircraft parts –
Spray painting aircraft parts can be done in a spray booth with a downdraft or cross-draft exhaust ventilation system to keep exposures below the OSHA PEL of 5 µg/m3.
Methods to reduce Cr(VI) exposure levels when spray painting assembled aircraft Spray booths may not be feasible when painting assembled aircraft or large aircraft parts. Controlling Cr(VI) exposure can be challenging and requires careful planning to protect workers. Some engineering controls, like dilution (general) ventilation, may not be effective when spray painting assembled aircraft (interior, exterior) and large aircraft parts (wings, tail sections, ailerons (wing turning mechanism, etc.) in hangers or other large buildings. OSHA’s Cr(VI) standard provides that where employees are painting aircraft or large aircraft parts, engineering and work practice controls must be used to reduce Cr(VI) exposures to or below 25 µg/m3 (8-hour TWA), unless the employer can demonstrate that such controls are not feasible. The employer must supplement engineering and work practice controls with respirators to achieve worker protection to the PEL of 5 µg/m3 (8-hour TWA).
Control methods to reduce worker Cr(VI) exposure during paint removal-
Sanding, grinding, and abrasive blasting to remove paint can be performed in spray booths or rooms with mechanical ventilation. In large hangers or rooms with only general ventilation, equipment can include local exhaust ventilation (LEV) to capture generated dust.
• Use handheld powered sanding, cutting, and grinding equipment with attached LEV connected to high efficiency particulate air (HEPA) filtered exhaust
• Do not use compressed air to blow dust off aircraft or parts. • Use HEPA filtered vacuums or wet methods (spray mist) to reduce dust. • Use ventilated, fully enclosed glove box abrasive blasting units for small objects.
• Conduct abrasive blasting in a dedicated room equipped with mechanical exhaust ventilation for large parts. More Information
For more information on hexavalent chromium exposure, visit OSHA’s website at www.osha.gov.