Lead poisoning results from many small exposures over a period of weeks or years. The brain and nervous system are particularly susceptible. Children less than 6 years of age are especially vulnerable because their brains and central nervous system are just developing and their smaller bodies take on a greater percentage of lead.
White lead was used as a covering pigment, a colorant and a rust inhibitor since the ancient Greek and Roman civilizations. In the United States, the durability of lead-based paints promoted their widespread use for wooden surfaces for more than two centuries.
Lead paint was banned in 1978. Because many San Francisco Bay Area homes were built prior to 1979, most of them contain some amount of lead paint. The good news is that so long as the paint is intact it’s safe. When the paint flakes or is sanded, friable lead particles become airborne and may be ingested.
The presence of lead paint does not mean that every homeowner should engage in a full-scale lead abatement project. Much like asbestos, if lead paint is maintained in good repair it poses minimal risk. But when paint fails, precautions should be taken to minimize dust and particles released.
Old painted surfaces that are peeling, chipping, flaking, or otherwise failing will provide a constant source of small particles of paint that can be ingested or inhaled. Moving surfaces that are painted can generate lead dust by friction. The dust is difficult to remove and may accumulate over a period of years. The friction of opening and closing of a window sash or a sticking door can generate lead dust.
Renovation work and paint removal projects can generate tremendous amounts of lead dust. Heated or burned lead surfaces produce lead fumes that can be easily inhaled.
Homeowners who undertake such projects should be aware that they may be contaminating their environment and endangering their health. In most cases, it is safer to leave intact paint layers undisturbed. Homeowners who undertake paint removal projects should be aware that they might be contaminating their environment.
Flat-painted surfaces pose much less danger than protruding, irregular surfaces. Floors, wainscoting and baseboards usually do not require abatement. Nor do intact painted surfaces on fixed window sashes, upper members of window or door frames, and ceilings.
If the need for lead paint abatement can be clearly demonstrated, or if the contaminated features and finishes are important to the preservation of the property’s historic character, abatement should be undertaken using the principles of minimal intervention.
I found a raft of information on two excellent Bay Area websites, www.aclppp.org and www.getleadout.org.
Here’s the best of it:
1. Isolate and restrict access to the work area. While it may not be possible to control all lead dust, simple measures can greatly reduce the degree of contamination. Plastic sheeting (6-mil polyethylene) sealed at its edges with duct tape, for example, is effective in keeping most lead dust within the immediate work area, where it can be picked up with HEPA vacuuming. Furniture, rugs, plants and other items should be removed from the work area prior to beginning work. Only workers directly involved in the project should enter the work area. Young children and pregnant women must stay out of the work area until cleanup has been completed.
2. Select the safest methods for paint removal. With the proper ventilation and protection chemical strippers is the method of choice. Scraping does not provide effective removal and sanding by hand or mechanically produces copious amounts of lead-impregnated dust. Avoid blowtorches or heat guns, as they produce toxic fumes.
3. Wear appropriate clothing. Disposable coveralls are recommended to minimize contamination of clothing by lead dust. Disposable shoe covers, to prevent tracking of lead dust outside of the work area, are recommended. Neoprene or butyl gloves are indicated when working with methylene chloride-based chemicals.
4. Use required safety equipment. A respirator is recommended. If any lead dust or lead fumes will be produced, a respirator with appropriate filters is necessary.
5. Cleanup. Recommended measures for cleanup after lead abatement procedures should consist of High Efficiency Particulate Air (HEPA) vacuuming and washing with trisodium phosphate (TSP) solution. Ordinary household vacuum cleaners will not pick up most lead dust.
6. Disposal. All lead dust, paint chips, equipment, supplies and materials used in abatement should be considered hazardous waste and disposed of in accord with local regulations.