SAN FRANCISCO – Consumers in the San Francisco area could soon be feeling guilty at the pump, as the cities of San Francisco and Berkeley begin requiring a new "carbon label" on the gas nozzle. The idea behind the label is to help keep the connection between behavior and climate change fresh in consumers’ minds, says SustainableBusiness.com.

San Francisco and Berkeley both passed legislation requiring gas station owners to put "climate change warning labels" on all gas pump nozzles. Labels will be required in those two cities beginning March 1, 2015, and stations that don’t comply risk fines of $100–$500.

The labels say how much carbon dioxide is emitted for every gallon of gas burned: "The U.S. Environmental Protection Agency (EPA) has determined that a typical passenger vehicle burning one gallon of fuel produces on average almost 20 pounds of tailpipe carbon dioxide (CO2), which the EPA has determined is the primary greenhouse gas that is contributing to recent climate change. This is a message from the city and county of San Francisco.”

While the Western States Petroleum Association (WSPA) has not announced whether they plan to fight the label rule in court (or in the court of public opinion), WSPA President Catherine Reheis-Boyd has described the rule as a violation of gas station owners’ First Amendment rights, as the government can't force a business to state information unless it prevents consumer deception.