The Food and Drug Administration will launch a new investigation into the safety of the caramel coloring found in many soft drinks, including Pepsi, Coca-Cola and Dr. Pepper.

The chemical, called 4-methylimidazole (4-MeI), has come under increased scrutiny ever since a 2007 study published by the National Toxicology Program found that long-term exposure to the substance increased mice's risk of developing cancer.

California's Proposition 65 law requires any product with 29 micrograms of 4-Mel to carry a warning label. But according to the Consumer Reports article, every 12-ounce sample of Pepsi One and Malta Goya, a drink brewed from barley and hops, contained more than 29 micrograms of the chemical.

"While we cannot say that this violates California's Prop 65, we believe that these levels are too high, and we have asked the California Attorney General to investigate," the group wrote in a statement.

In all, Consumer Reports tested 81 cans and bottles from a variety of brands purchased in California and New York between April and September 2013. Twenty-nine additional samples followed, this time of those brands that had contained more than 29 micrograms per can or bottle. The results showed that 4-Mel levels tended to be much higher in the samples coming from New York, although Pepsi, Diet Pepsi, Pepsi One and Malta Goya all surpassed the 29 microgram mark in California in at least one of the samples.

According to an email from a PepsiCo spokesperson sent to Consumer Reports, "When the regulatory requirements changed in California, PepsiCo moved immediately to meet the new requirements."

The company then followed with a statement that argued the law has to do with per day exposure rather than per can exposure, Consumer Reports said.

Future studies will be designed to "inform the FDA's safety analysis and will help the agency determine what, if any, regulatory action needs to be taken," agency spokeswoman Juli Putnam said, according to The Associated Press.