Consider the dose
The state of California in 2011 placed 4-methylimidazole (4-MEI) on its Proposition 65 list of substances that may cause cancer. The ruling meant that businesses must provide a warning if they manufacture or sell products in California that cause exposure to significant amounts of 4-MEI, which is found in Class III and Class IV caramel color used in soft drinks.
The California ruling may call into question what “significant amounts” are.
Findings from the National Toxicology Program, Research Triangle Park, N.C., in January 2007 were the basis of the California ruling. The National Toxicology Program gave rats 625 parts per million (p.p.m.) to 2,500 p.p.m. of 4-MEI in their feed. Mice received 312 p.p.m. to 1,250 p.p.m. of 4-MEI in their feed. Researchers concluded 4-MEI caused lung cancer in mice and that 4-MEI may have been associated with female rats developing leukemia.
The results failed to sway the U.S. Food and Drug Administration.
“These N.T.P. studies were conducted in rodents at levels of 4-MEI that far exceed current estimates of human exposure to 4-MEI from the consumption of Class III and Class IV caramel coloring in food products such as colas,” the F.D.A. said and added, “Based on the available information, F.D.A. has no reason to believe that there is any immediate or short-term danger presented by 4-MEI at the levels expected in food from the use of caramel coloring.”