Scraping and sanding old walls can create a dust that is very harmful. (iStockphoto)

In 1978, the federal government banned the use of lead-based paint in homes after long-term studies showed that lead causes severe health problems, especially in children under 6, damaging their nervous systems even before birth.

Although lead-based paint is off the market, millions of homes still have it on the walls. As long as it’s in good condition, it probably isn’t a hazard. But scraping and sanding changes that, creating dust that can be very harmful.

Because of these dangers, in 2008 the Environmental Protection Agency issued the Renovation, Repair and Painting (or “RRP”) Rule, which requires contractors working in pre-1978 homes to be lead-safe certified and use special work practices to contain and clean up dust. Companies can achieve certification by applying to the EPA (or an authorized state) and having their workers or supervisors take a course on work practices to minimize exposure to lead during renovation, repair and painting projects.

Even small projects are covered by the law, which kicks in when more than six square feet of painted surface inside or 20 square feet outside are disturbed. So even a small painting project or single window replacement is covered by the rule. The law also applies to landlords who renovate rental properties, but it doesn’t apply to DIYers — although you’ll obviously want to do everything you can to protect your kids from exposure to lead-based paint.

Most homeowners are unaware of the law, but all contractors should be aware of their obligations. Unfortunately, many companies still aren’t doing what they should. Washington Consumers’ Checkbook strongly urges anyone who lives in a pre-1978 home to hire only lead-safe-certified contractors and demand that workers follow the law when working in areas where lead-based paint could be disturbed.

A good place to start looking for information about lead is epa.gov/lead. The ratings at checkbook.org will also help you find responsible contractors.

To evaluate the risks of lead-based paint in your home, do the following:

• Have your children tested. According to the American Academy of Pediatrics, “there is no safe level of lead exposure for children.” All children should be screened for lead at ages 1 and 2. For more information, read “What Do Parents Need to Know to Protect Their Children?” and other information available at the Centers for Disease Control and Protection’s website (cdc.gov/nceh/lead).

• If a blood test indicates your child has been exposed to lead, get a lead-safe-certified professional to check your home for lead. A lead-paint inspection performed by a certified contractor tells you only about the lead content of painted surfaces — not whether they are a hazard or how to deal with them. A risk assessment conducted by a certified inspector will indicate sources of serious lead exposure and ways to eliminate them. The risk assessment is thorough and expensive — about $500, plus $10 to $15 per lab sample — but if your child has been exposed, you need to eliminate additional exposure.

• If your home was built before 1978, ask prospective contractors to show proof of their lead-safe certification. In any contracts you sign, include a statement saying the contractor “will follow EPA regulations for containing the work area and minimizing the generation of lead-paint dust.”

The tasks a contractor — and you, if you’re doing the work — should do to minimize lead exposure depend on the work being done, but in general the following steps should be taken:

• Children and women who could possibly be pregnant should stay out of work areas until work and cleanup is complete.

• Identify in advance any surfaces that may contain lead-based paint and that might be disturbed while work is performed. Unless absolutely necessary, don’t disturb these surfaces by sanding, scraping or cutting.

• If possible, take materials containing lead-based paint outside to work on.

• Seal off rooms where work is performed.

• Remove all furnishings in the work area.

• Workers should wear protective clothing, including respirators.

• Properly dispose of all waste generated during the work.

• Power tools used to sand or sandblast should be equipped with shrouds and HEPA-filtered vacuum attachments.

• After work is completed, thoroughly vacuum and clean all surfaces.

• After cleanup, test to determine whether cleanup was adequate.

As you can see, it takes effort to follow the law. But don’t assume this extra work comes at a steep price — and don’t allow companies to use the threat of sky-high prices to persuade you to allow them to skimp on the rules. Checkbook spoke with owners of top-rated painting businesses; most routinely don’t charge more when they have to follow the lead-safe law, and those that do charge more assess a $100-$200 fee for large jobs. Window installation companies we spoke with charge up to $75 more per window when they have to follow the EPA’s work rules. Such a surcharge seems a small price to pay to eliminate a potential health hazard to your kids.

Washington Consumers’ Checkbook magazine and Checkbook.org are a nonprofit organization with a mission to help consumers get the best service and lowest prices. We are supported by consumers and take no money from the service providers we evaluate. You can access all of Checkbook’s ratings of area service providers free of charge until Dec. 1 at checkbook.org/washingtonpost/lead.