Attorney general Bill Lockyer argues that the state's anti-toxics law, Proposition 65, requires companies to warn consumers about products containing chemicals known to cause cancer or birth defects.
Acrylamide, a carcinogen that is created when starchy foods are baked, roasted, fried or toasted, was placed on the list in 1990. But some food companies remain reluctant to highlight the potential danger in snack products such as fries and potato chips.
The defendants in the lawsuit include heavy weights such as Burger King, Frito-Lay, Heinz, KFC and McDonald's.
"In taking this action, I am not telling people to stop eating potato chips or French fries," said attorney general Bill Lockyer.
"I know from personal experience that, while these snacks may not be a necessary part of a healthy diet, they sure taste good. But I, and all consumers, should have the information we need to make informed decisions about the food we eat.
"Proposition 65 requires companies to tell us when we're exposed to potentially dangerous toxins in our food. The law benefits us all, and as Attorney General, I have a duty to enforce it."
But many food makers remain resolutely opposed to such a warning, fearing that such labeling would needlessly scare consumers. They argue that obesity, over-consumption and alcohol are much more likely to increase the risk of cancer than trace levels of carcinogens in food.
However, pressure has been mounting on food companies to better label their foods ever since scientists in Sweden confirmed the link between starchy foods and acrylamide in 2002. Public health bodies have become increasingly vigilant; according to the Environmental Law Foundation (ELF), dozens of potato chips contain excessive levels of acrylamide without any warning whatsoever.
For every product the pressure group tested, a one-ounce serving eaten daily exceeded levels that require a cancer warning under Proposition 65.
Lockyer has made efforts not to appear so confrontational. He claims that he intends to work with the defendants in the case to find a way to effectively give consumers information about the acrylamide in their products, while at the same time preventing undue public alarm and unnecessary warning signs concerning foods that contain insignificant amounts of the chemical.
The Attorney General's action is not the first to seek consumer warnings for these foods. A private suit filed in 2002 by the Committee for Education and Research on Toxics (CERT) named McDonald's and Burger King as defendants, and is pending in Los Angeles County Superior Court.
Another set of two private suits filed on 3 August 2005 by Environmental World Watch (EWW) identified a number of the same defendants as the Attorney General's suit. Additional actions were filed on 25 August 2005 by the ELF.
The FDA is currently investigating acrylamide in various foods, including bread, cereal and coffee, but has not issued any warnings. A list from March 2004 shows the acrylamide levels - in parts per billion - of many brands of food. This list can be found here.