How Much Lead is Safe?

Deaths from lead poisoning are now rare, but doesn't mean lead safe. Lead can cause developmental delay, neurologic problems, kidney disease, & anemia.


My wife and I just found there is lead on the back of a paint chip from a window sill. The dust from the floor tests negative. Should we be concerned about living here during a pregnancy and afterwards with a newborn? How do we go about finding out how much lead there is in the apartment? How much lead is safe? Thanks.
Larry Buxbaum, M.D. - Hospital of the University of Pennsylvania

Dr. Greene's Answer

In that tiny paint chip, the past and the future intersect. A generation ago in that same space, a couple stood in a freshly painted apartment, perhaps with a young child. Now that child is grown and gone. You stand with your wife, holding a chip of the past, and prepare for the future. You, however, see with eyes a generation wiser, aware that danger lurks in lead paint.

Deaths from lead poisoning are now rare, but it is not unusual for a child’s blood to contain enough lead to cause intellectual and developmental delay, neurologic problems, kidney disease, and anemia. Children absorb 40-50% of the lead that gets into their mouths (adults only 10%). Even small amounts of lead can produce high concentrations in the blood of young children because their bodies are small. Since children’s brains are still developing, the effect of lead poisoning can be especially damaging.

Sources of Lead

Today, lead-based paint is the most common source of lead poisoning in children. Over many years, painted surfaces crumble and become common household dust. This dust coats the objects that curious children put in their mouths. Adults can also ingest lead in this way. It is the most common way for the lead in paint to get into a person (and it is reassuring that your dust tested negative). Children will also chew on window sills or other painted surfaces. Sometimes they will eat old paint chips.

Lead is used to make paint last longer. Prior to World War II, heavily lead-based paints contained as much as 40% lead by dry weight. The amount of lead in household paint was reduced in 1950, and reduced even further in 1978. Most apartments and houses built before 1950 still contain paint with high levels of lead, particularly on doors and around windows. Later household paints may test positive for lead, but generally contain much smaller amounts.

Testing Your Home for Lead Safety

You can find out about your own home by testing the concentration of lead in your paint chips, or by having a certified lead inspection or risk assessment. Be sure the lead concentration is measured in milligrams per square centimeter (as opposed to parts per million), so that later layers of paint don’t hide the risks. For a more thorough evaluation, lead inspectors will tell you the lead content of all the painted surfaces in your home. Risk assessors will go a step beyond this and identify hazards such as peeling paint or lead dust, and give you a report on what can be done to fix the problems.

A common response to a positive lead test is to strip the old paint. DON’T. The process of removing old paint (especially sanding, scraping or burning) can produce large amounts of lead dust. This would be the greatest danger for your pregnant wife and future child. Lead poisoning is very common during remodeling. Use a contractor skilled in lead abatement to enclose or remove the lead from your apartment.

Lead Remediation

For information on finding inspectors, assessors, and contractors, and finding local laboratories that can test lead concentration in your apartment, contact your local Health Department and ask for the Department of Environmental Health. Another great resource is the National Lead Information Center at 1-800-424-LEAD. Lead specialists are available through this hotline to answer your questions and will send you detailed information on preventing lead poisoning. Requests for written information can also be submitted through their website at The National Safety Council also has some excellent information on lead through their website at

Since the chip tested positive for lead, it is wise not to place a crib, play-pen, or high chair where paint is peeling or can be chewed. Keep your apartment as dust free as possible, regularly wet mopping the floors. In particular, wipe window sills with water and a household detergent. Also, good nutrition (fresh fruits and vegetables, plenty of calcium and iron) causes less lead to be absorbed into the body. The lead that is absorbed will do less damage.

That little chip of paint, that intersection of past and future, is also a mirror. You are already becoming a father. I wish you all the best.

Last medical review on: February 01, 2004
About the Author
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Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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