Case 4 - Two spray painters, a curtained corner and asthma
A vehicle body shop in Thika employs twelve people, two of whom spray-paint cars with a two-pack paint whose hardener contains an isocyanate and whose thinner is a solvent mixture. The “booth” is a curtained corner of the workshop with a homemade fan that extracts into the yard; when it is switched on, paint mist drifts back into the preparation area, where two other workers sand body panels. Neither painter has had a pre-employment or periodic medical examination. Both have complained of headaches and dizziness after a morning’s work, and one now wheezes and coughs at night, though he is well at weekends. The painters wear disposable dust masks bought from a supermarket. They eat lunch beside the spray area, wash their hands in solvent, and hang their overalls with their family clothes in a shared locker. There is one tap in the yard, no soap, and no warm water.
1. Identify the health hazards, the routes of exposure, and explain why the dust masks are inadequate.
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Two different exposures, both serious.
- Solvent vapour (thinner, typically toluene/xylene type): inhaled and also absorbed through the skin. The headaches, dizziness and drowsiness are central nervous system symptoms - a sign of overexposure, not “just the smell”. Longer-term effects include neurological, liver and kidney damage.
- Isocyanate hardener: a potent respiratory sensitiser. There is no exposure level at which sensitisation can be ruled out, and once sensitised a person reacts to very small amounts. Continued exposure can cause occupational asthma that persists after leaving the job. The painter who wheezes at night but is well at weekends shows the classic pattern; he should be referred to a doctor now and removed from isocyanate work pending assessment.
Routes of exposure Inhalation of mist and vapour while mixing, spraying and cleaning the gun; skin contact during mixing and gun cleaning and during hand-washing in solvent; ingestion from eating and drinking in the contaminated area.
Why supermarket dust masks are useless here
- A nuisance-dust mask does not seal to the face - especially with stubble or a beard - so vapour and fine mist leak around the edges.
- It does not remove solvent vapour and is not certified against isocyanate mist; it filters coarse dust only.
- It gives a false sense of protection, which is worse than none, because the wearer stays in the exposure believing he is protected.
Correct protection is supplied-air breathing apparatus or an air-fed hood in a proper booth. As a documented stopgap only: fit-tested FFP3 or A2P3 combination, sealed goggles and nitrile gloves. Record both men in the occupational disease register and report the suspected occupational asthma to DOSHS.
2. Design the control package for the spray area, including health surveillance and welfare arrangements.
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Controls, in the hierarchy
- Substitute: quote for a water-based or low-isocyanate system for suitable work. Where the customer specification demands 2K, mix only what the job needs, keep the hardener sealed and decant in a closed system.
- Engineer: a proper spray booth with filtered extraction, negative pressure and make-up air - or at minimum a cross-draught booth with extraction at the work and filtration before discharge. Add extraction for gun cleaning, spark-proof/ATEX electrics, and separate the sanding/preparation area so it is not downstream of the spray.
- Administrative: a written assessment built from the safety data sheets; a permit or authorisation listing who sprays and when; nobody else in the zone during spraying; wet clean-up; closed containers; solvent waste collected; supervisor checks.
- PPE: individually issued air-fed RPE or fit-tested A2P3 with goggles, nitrile gloves, coveralls; stored clean; replaced on schedule; never shared.
- Health surveillance: pre-placement questionnaire and spirometry for anyone entering spray work; at least annual spirometry and symptom review by an occupational health practitioner; immediate referral and removal from exposure if symptoms appear. Records are confidential but available to the worker and to the DOSHS medical officer; statutory medical examinations apply to this hazardous work.
- Welfare: double locker/change area with clean and dirty sides; showers with warm water and soap; employer-laundered overalls never taken home; separate storage of clean clothing; a clean canteen away from the shop; drinking water; no eating, drinking or smoking in the work area.
Sequencing: the RPE and restricted access go in this week; the booth, extraction and health surveillance are dated actions with named owners, written into the risk assessment.
3. The owner says a proper booth is too expensive for twelve employees. How should the committee respond?
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Start from the duty, not the price. The employer must control exposure so far as is reasonably practicable, and the assessment must show why each control was chosen. Cost is a factor in “reasonably practicable”, but it is weighed against the likelihood and severity of harm - and here harm has already occurred.
The evidence is against him
- Two workers have symptoms; one has the weekend-well, night-wheeze pattern of occupational asthma. If he becomes sensitised, he may never be able to work with paints again, and the employer’s liability under the Work Injury Benefits Act follows the exposure.
- A booth is standard practice in the trade, not a luxury; a body shop that sprays 2K paint without extraction is the outlier.
Construct the argument, not the confrontation
- Ask for three quotes and a phased plan with dates: interim package now (fit-tested RPE, extraction at the work, restriction of access to the spray zone, health surveillance, no eating in the area), full booth by an agreed date.
- Compare the booth cost with a single asthma claim, lost painter, or a prohibition notice that stops all spraying for weeks.
- Offer cheaper first steps: reduce the volume sprayed, outsource full resprays, switch suitable jobs to water-based, and cut solvent use in gun cleaning.
- Record the discussion and the decision, including the interims and their review dates, in the committee minutes and the risk assessment.
If the owner still refuses and spraying continues, the committee should put its recommendation in writing and escalate to the area occupational safety and health officer; the written record protects members and shows the workforce was warned.