Lead safety on a pre-1978 repaint

There are two regulatory systems running on an old-house repaint and they protect different people. One governs the dust that stays in the building after the crew leaves — the occupant's problem. The other governs the air inside the respirator of the person holding the sander for eight hours — the worker's problem. Homeowners generally only hear about the first. The second is the one that decides whether a company is genuinely equipped for this work.

The details

The exposure numbers are the spine of it, and North Carolina adopts them from the federal construction standard. OSHA lead PEL 50 µg/m³ is the frame: where airborne lead exceeds an action level of 30 micrograms per cubic metre, the employer must run an air monitoring program, and above the permissible exposure limit of 50 micrograms per cubic metre the employer must add engineering controls, respiratory protection, personal protective equipment, medical surveillance and worker training. Those are duties owed by a company to its own employees under 29 CFR 1926.62, enforceable whether or not a homeowner ever asks.

Why sanding in particular. Intact paint on a wall is a solid; the hazard is in what turns it into an aerosol. Power sanding, dry scraping, abrasive blasting and open-flame or high-heat removal all convert a stable film into respirable particulate in seconds, and an enclosed porch or a crawlspace concentrates it. A crew working a wind-scoured exterior elevation and a crew working an interior stairwell on the same house can be in completely different exposure worlds by lunchtime, which is exactly why monitoring is a measurement rather than a judgement.

The scale of the risk is not speculative. About three-quarters of pre-1978 homes contain lead paint — EPA's own estimate is that about three-quarters of pre-1978 American housing still holds some lead-based coating, and the residential ban took effect in 1978. On a coast with a large stock of mid-century cottages, a painting crew that works old houses regularly is working near lead regularly, and the arithmetic of a career matters more than the arithmetic of a single job.

Competence here is certified rather than assumed. 40 CFR 745.90: becoming a certified renovator or dust sampling technician requires successfully completing the appropriate course accredited by EPA or by an authorised state program, which in North Carolina runs through the state's own program. That course is where containment, wet methods, HEPA vacuuming, prohibited practices and the cleaning verification routine stop being folklore and become procedure.

And the certification is a perishable good. Refresher course required to maintain certification — under 40 CFR 745.90(a) an individual must complete an accredited refresher course on the schedule the certifying program sets in order to keep renovator or dust sampling technician certification current. A certificate issued years ago with no refresher behind it is not evidence of a current qualification, which is why the on-site paperwork is dated and why anyone reviewing it should look at the date first.

What all this looks like on a real job, from the outside: plastic that is taped rather than draped, a HEPA vacuum rather than a shop vac, wet scraping rather than a belt sander and a cloud, a crew in fitted half-masks rather than paper nuisance masks, debris bagged at the work area instead of swept across the yard, and boots and clothing that do not travel home to the crew's own families. A homeowner cannot audit an air sample, but anybody can see whether a company works like one that takes the measurement seriously.

The occupant's rule and the worker's rule are separate, and only one of them has a number in micrograms attached. Ask how a company monitors exposure and when its renovators last refreshed, and you will learn more about the operation in two questions than a portfolio of finished rooms can tell you.