Precautionary policies in local government: green chemistry and safer alternatives.

Local governments like the City and County of San Francisco have shouldered the burden of toxic chemicals released into the environment through the substantial costs of health care, environmental cleanup, and infrastructure to purify drinking water, manage wastewater, and manage solid waste. Cities can no longer afford to wait for federal regulation to prevent toxic chemicals from appearing in products used locally. San Francisco's Precautionary Principle Policy calls on the City to act on early warning signs of harm and to use the best available science to identify safer alternatives.