Each year, thousands of children suffer injuries in bathtubs. Slipping, falling, scalding and drowning cause most of the injuries and deaths, but just as dangerous and very prevalent is a little known hazard.

Several cases of acute lead poisoning in young children have been traced to their bathtubs. This source of lead is often overlooked, but studies revealed that 62 percent of the porcelain tubs in American households have lead leaching into the bath water, placing millions of children at risk.

Bathtub manufacturers used, and some still use, lead in the glaze for their tubs. If the bathtub's surface is damaged, due to abrasive cleaners, chips or erosion, lead can seep through and poison anyone who ingests it. Since very young children often drink their bath water and put wet fingers in their mouths, they are in great danger of lead poisoning.

"You should test your bathtub glaze for lead, especially if it's old," advised Brian Olson, owner of Gemini Tub Repair, based in Bainbridge PA. "We offer free lead testing, and 75 percent of the 20-year-old porcelain tubs I've tested have leachable lead on the surface. For five-year-old bathtubs the figure is about 10 percent."

"If your bathtub tests positive for lead, you don't need to get rid of it," said Olson. "You can solve the problem and save a lot of money by having your bathtub professionally refinished, rather than replaced."

Exposure to even tiny amounts of lead can cause a variety of health problems in children. According to the National Safety Council, a lead particle the size of a single grain of salt can cause a child to register an elevated blood lead level.

Children under the age of seven are especially at risk because their brains and central nervous systems are developing. If exposed during these formative years, lead poisoning can drastically affect a child's development. Its effects may not appear until many years after the initial exposure.

Symptoms of lead poisoning include stomachache, hyperactivity, muscle pain, weight loss, learning disabilities, anemia and convulsions. These symptoms usually persist for about two weeks from time of exposure, and then settle into the organs, bones and hair. Any damage done to a child's body is irreversible, permanent and untreatable.

The Environmental Protection Agency estimates that over 57 million U.S. homes have dangerously high lead levels, with bathtubs being a fairly new identified source. The Centers for Disease Control and Prevention regard lead poisoning as the number one preventable childhood illness in America, but estimate that 434,000 children under the age of six have elevated levels of lead in their blood.

"Many families spend large sums and countless hours trying to find the cause of their children's abnormal blood lead levels, not realizing it may be their bathtubs," Olson said. "If you suspect the tubs in your home contain lead, you should have them tested."