Case Study: Spray Painting Exposure Monitoring

Case Studies · Case Studies overview

Anonymised case study of a combined HDI and solvent biomonitoring programme rolled out across a 22-site UK automotive refinish network operating ~140 sprayers.

Network scenario

Multi-site MVR body-shop network, 22 sites, ~140 sprayers using HDI-based 2-pack clearcoats. Mixed booth ages and LEV maintenance regimes across sites. Network H&S team commissioning standardised biomonitoring across all sites.

Exposure concern

HSE focus on isocyanates in MVR; site-to-site variability in supplied-air RPE compliance suspected. Air monitoring alone considered insufficient to characterise compliance variability.

Monitoring approach

Urinary HDA end-of-shift, all sprayers, twice per year. Standardised sample-collection kit and instructions across all sites. Centralised analysis at a single UKAS lab to allow direct site-to-site comparison. Methylhippuric acids added for thinner-system carriers where solvent exposure justified.

Interpretation themes

Site cohort GMs ranged from 5% to 75% of internal action level. Strongest predictors of low cohort GM: positive-pressure visor air supply (vs ambient-air systems), documented monthly visor fit checks and booth LEV TExT compliance.

Control improvements and lessons learned

Network-wide investment in positive-pressure supplied-air systems; centralised LEV TExT contract; quarterly fit-test cycle. Inter-site league-table reporting drove cultural change. Lesson: variability is a programme-level metric, not just a site-level one — central reporting unlocked action.