Public health attorneys in California have potato chip makers in their sights for not listing a cancer-causing chemical present in many brands.

That chemical is acrylamide.

It is an industrial chemical used in plastics, pesticides and sewage treatment that also can occur when starchy foods, such as chips, are processed at high temperatures. The World Health Organization has said acrylamide may be responsible for up to one-third of all cancers caused by diet, as demonstrated by laboratory animal studies.

Acrylamide is already on California's list of chemicals known to cause cancer, but some chipmakers haven't listed it on their product packaging as required by Proposition 65 statute. The attorneys have filed Proposition 65 notices with the manufacturers of Lays, Pringles, Kettle Chips and Cape Cod chips.

Research has shown those brands have unsafe levels of acrylamide in some of their chip varieties.

The study looked at one ounce servings, which ranged from 11 to 20 chips depending on the brand, and determined the acrylamide content was substantially more than the 0.2 micrograms per day amount which prompts the Proposition 65 warning.

The brands tested and cited for high levels of acrylamide are:

Lay's Baked!, Lay's Stax BBQ, Lay's KC Masterpiece, Lay's Natural Country Barbecue, Lay's Light KC Barbecue Masterpiece, Pringles Snack Stacks (Pizzalicious Flavor), Pringles Sweet Mesquite BBQ, Kettle Chips Lightly Salted, Kettle Chips Honey Dijon, Cape Cod Robust Russet and Cape Cod Classic Chips.

Processed food manufacturers have reportedly asked Gov. Arnold Schwarzenegger for a exemption to Proposition 65 labeling for foods with carcinogens caused by heat processing.

The governor's office is expected to announce its decision by August.