Plastic baby bottles and water bottles are safe, a federal health official said Tuesday, seeking to ease public concerns about the health hazards of a chemical used in the products. The National Toxicology Program said in a recent draft report that there is "some concern" that bisphenol A can cause changes in behavior and the brain, as well as reduce survival and birthweight in fetuses. It drew its conclusions from animal studies. Canada has announced its intention to ban the use of the chemical in baby bottles, and US lawmakers have introduced legislation to ban bisphenol A in children's products. Small amounts of bisphenol A can be released as plastics break down. Dr. Norris Alderson, the Food and Drug Administration's associate commissioner for science, said, however, that the level of exposure was safe. Some studies had reported higher release levels than projected by the agency, but many of those studies were conducted under unrealistic conditions, he said. "Although our review is ongoing, there's no reason to recommend consumers stop using products with (bisphenol A)," Alderson told a House subcommittee. Bisphenol A also is used in many other products, from helmets to compact discs to goggles. Any ban of the chemical could result in less effective protection for children who wear the protective gear, said Dr. Michael Babich of the U.S. Consumer Product Safety Commission. About 99 percent of human exposure to the chemical comes from diet. Dr. Ted Schettler, director of the Science and Environmental Health Network, took a more cautionary view. He told lawmakers that animal testing showed low-level bisphenol A exposures during fetal development can alter development of the prostate gland and breast. These changes could increase the risk of cancer, he said. "Do we wait for irrefutable proof of harm in people before taking action?" he asked. The House Energy and Commerce subcommittee also is reviewing the safety of phthalates, which is used to make vinyl soft and flexible. Phthalates are used in medical devices, cars and toys. Dr. Earl Gray, a toxicologist at the Environmental Protection Agency, said he had serious concerns about the potential effects in children who are exposed to phthalates from IV tubes. He said that although the level of exposure for most people is low, there can be exceptions. In rats, phthalates have been shown to cause liver cancer and reproductive tract malformations in offspring. Bills filed in Congress would prohibit the manufacture and sale of certain children's products that contain phthalates.