SAN FRANCISCO -- Several popular baby bottle brands have been found to leach potentially harmful levels of a toxic chemical linked to developmental, neural and reproductive problems, according to a new study released Tuesday.

The independent laboratory study was conducted in cooperation with the Environment California Research and Policy Center to test whether bisphenol A, a chemical used to make clear plastic for consumer products, including baby bottles, was released into the liquids the bottles contained, Environment California spokeswoman Rachel Gibson said.

The group tested five popular baby bottle brands -- Avent, Dr. Brown's, Evenflo, Gerber and Playtex -- all five of which leached bisphenol A at levels "found to cause harm in numerous laboratory animal studies," Gibson said.

According to Gibson, the plastic material in containers breaks down through use and releases bisphenol A into liquids and food.

Bisphenol A has been linked by scientists to cancers, impaired immune function, early onset of puberty, obesity, diabetes and hyperactivity, Gibson said.

Gibson said though San Francisco currently prohibits the use of bisphenol A in toys and child care products for children under 3 years old, her group is calling on California and the federal government to eliminate this and other harmful chemicals from products used by children.

Environment California is also calling for required product manufacturer labeling and reforms in chemical manufacturers' policies.

The group recommends consumers choose glass or "safer-plastic" baby bottles. In addition, the group advises against heating up food or drinks in plastic containers, and using harsh dishwashing soap and hot water, as these practices can speed up the rate of leaching, according to Gibson.