New research suggests macaroni and cheese powder contains high concentrations of potentially dangerous chemicals.

The Coalition for Safer Food Processing and Packaging, the group behind KleanUpKraft.org, tested 30 cheese products for phthalates, a group of plastics used to make plastics more flexible. Phthalate levels were more than four times higher in macaroni and cheese powder.

The study, which has not been published in a peer-reviewed journal, was paid for by environmental advocacy groups.

While the coalition says phthalates pose a serious threat to the health of pregnant women and children, the Centers for Disease Control and Prevention reports health effects from exposure to low levels of the chemicals are unknown. That said, some phthalates have altered lab animals' reproductive systems, the CDC says.

Phthalates can be found in a host of home and personal care products (think: soaps, hair sprays, raincoats, detergents and flooring). The chemicals aren't meant to be in food, or find their way into human bodies. Some phthalates have been banned from children's toys and products. A 2014 report to the U.S. Consumer Product Safety Commission warned of their health effects, especially in children and pregnant women.

But, it's clear people are eating them. The CDC has found phthalate exposure is widespread in the U.S. by testing urine as shown in the Fourth National Report on Human Exposure to Environmental Chemicals. Adult women have the highest levels of phthalate metabolites in their systems, largely credited to body washes, cosmetics and other personal care products.

Kraft denies using the chemicals.

“We do not add phthalates to our products,” Kraft spokesperson Lynne Galia said in an emailed statement. “The trace amounts that were reported in this limited study are more than 1,000 times lower than levels that scientific authorities have identified as acceptable."