Waterborne Paints Used in Automotive Collision Repair The Dark Side of … Shiny Cars: Steve Whittaker, Ph.D. Local Hazardous Waste Management Program Public Health – Seattle & King County

Collision Repair in King County, WA ~300 shops Industry consolidation: ABRA CARSTAR Fix Auto Gerber Kirmac Maaco

Typical paint job Spray Primer/ Sealer Bake dry Spray basecoat Air dry Spray clear coat 10-20% shops in King County, WA using waterborne basecoats

Solvent-based vs. Waterborne 85% organic solvents, 15% solids 10% organic solvent, 70% water, 20% solids Exempt solvents ( ozone potential) Common solvents: methyl ethyl ketone, methyl isobutyl ketone, xylene, toluene, n-butyl acetate, ethyl benzene, 1-methoxy-2-propyl acetate, and 2-heptanone Exempt VOCs, polar compounds as carrier (EGME), and other solvents 50% overlap for each pass 75-80% overlap required Bake Cycle (120-175 F) Dry Cycle (room temp) Specialty blowers

LHWMP’s study Visited 10 shops that used waterborne basecoats Monitored basecoat exposures in 11 painters Measured booth performance Observed work practices, waste management

What we found – The Good All waterborne basecoat exposures a fraction of occupational exposure limits (barely above detection limits) PPE mostly adequate – except when it wasn’t Painters REALLY like waterborne basecoats: Faster production cycles Paint goes on easily (after adjustment) No VOC odor Great match for OEM colors Mixed paints can be stored and reused

What we found – The Not So Good Not one spray booth conformed to OSHA air flow requirements. Overspray leaking from booths Prep stations were even worse! Spray booth Prep station

What we found – The Not So Good Waterborne gun cleaning: Enclosed pneumatic system best with water-based cleaner and maybe acetone final rinse BUT – old habits die hard: Aerosol cans (MeCl) Lacquer thinner

What we found – The Not So Good Spraying waterborne gun cleaning rinsate on mixing room floor!

What we found – The Not So Good Waterborne waste management: Confusion with residential advice to solidify and throw in garbage Wet paint thrown in garbage Sprayed on cardboard, baked, and thrown in garbage Waterborne waste rarely characterized (persistence) or managed by a vendor

The Bottom Line Waterborne basecoats likely safer alternatives to solvent-based paints Incentivize shops to switch to waterborne products? BUT – help needed with: Booth maintenance & performance Gun cleaning Waste management

Acknowledgements Grace Liao, LHWMP Graduate Intern (UW) Noah Seixas, Professor (UW) Marty Cohen, Senior Lecturer (UW) Larry Brown, LHWMP staff Brad Cleveland, LHWMP Graduate Intern (UW) Kristina Blank, LHWMP Graduate Intern (UW)