1. 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

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

3. 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

4. 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 ( F)
Dry Cycle (room temp)
Specialty blowers

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

6. 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

7. 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

8. 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

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

10. 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

11. 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

12. 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)