Both chemicals -- which are used to harden or soften plastic products -- can leach out of the plastic in baby toys and products every time an infant puts it in its mouth, causing possibly severe health problems.
San Francisco's law is modeled after a ban that went into effect in the European Union earlier this year, after rising concerns over the health consequences of the buildup of industrial chemicals in the human body came to light. For instance, a recent study by Harvard researchers appearing in The Lancet found that hundreds and possibly thousands of common chemicals are causing widespread brain disorders in children.
Many San Francisco companies that manufacture and sell baby products -- such as teething rings, dolls and waterproof books -- say they will comply with the ban, but find it unnecessary, claiming their products only contain "safe" levels of the hazardous chemicals.
The U.S. Environmental Protection Agency says its decades-old guidelines on "safe" human exposure to the chemicals fail to take into account hundreds of recent studies that link the chemicals with serious health disorders.
Representatives from the Food and Drug Administration and the Consumer Product Safety Commission -- which is in charge of toy safety -- say no plans are in place to pose new restrictions on the chemicals that take into consideration the latest research.
Makers of the chemicals bisphenol A and phthalates say the FDA and CPSC are correct not to reassess safety levels, claiming that low levels of exposure are of no concern to consumers.
However, hundreds of studies on the chemicals have linked them to malfunctions in children's developing organs and reproductive systems, as well as breast cancer, prostate cancer, malformed sexual organs, low sperm counts and disruption of the endocrine system.
A Japanese study found that babies who put products containing bisphenol A into their mouths can leach significant levels of the chemical from the plastic. A separate Tufts University study found that pregnant rodents exposed to a mere fraction of the level of bisphenol A considered "safe" by the EPA for a baby to consume produced changes in the rats' mammary tissues that are associated with breast cancer.
A majority of the studies in recent years that found the chemicals safe were funded by chemical corporations.
Because manufacturers are not required to list ingredients in toys, it can be difficult for parents to choose products that do not contain bisphenol A or phthalates. However, Mary Brine, founder of Making Our Milk Safe (MOMS), recommends parents purchase toys and products made without plastics, such as glass baby bottles.
Consumer health advocate Mike Adams recommends parents educate themselves on the health hazards of toxic chemicals in everyday products by reading Randall Fitzgerald's "The Hundred-Year Lie."