Why you should definitely make mac and cheese from scratch from now on

July 14 is National Macaroni and Cheese Day—which should be a major cause for gouda celebrations. But this year’s holiday is looking to be more controversial than cheesy, thanks to some recent, not-so-yummy research.

A just-released study (from activist group The Coalition for Safer Food Processing and Packaging) says everyone’s favorite boxed comfort food is filled—like seriously filled—with chemicals. Now, a dozen national health and food safety groups are calling on Kraft, the Big Cheese of the mac world, to push for industry-wide change to get rid of these toxins.

“The phthalate concentrations in powder from mac and cheese mixes were four times higher than in block cheese and other natural cheeses like shredded cheese, string cheese, and cottage cheese.”

The chemicals in question—and in your cheese powder-filled box—are phthalates. These hormone-disrupting chemicals have been linked to birth defects, development problems, and altered thyroid function, and they’re serious enough that they’ve been banned from children’s teething rings and rubber duck toys. But they haven’t been banned from foods, and The New York Times reports that phthalates may still be present in high concentration in macaroni-and-cheese products.

Two million boxes are sold in the United States every day. And, according to the study sampling 30 cheese products (some of which were labeled organic), 29 contained phthalates (with the highest concentrations in the super-processed powder formulations).

“The phthalate concentrations in powder from mac-and-cheese mixes were four times higher than in block cheese and other natural cheeses like shredded cheese, string cheese, and cottage cheese,” Mike Belliveau, executive director of the Environmental Health Strategy Center, tells the Times. A spokesperson for the Food and Drug Administration adds that the organization “continues to monitor literature and research on these compounds as it becomes available.” (In other words, they’re still not banned.)

Pro tip: Next time you’re tempted to reach for that little blue box, consider opting for a DIY version instead.

Another option: Make it with vegan cheese, or one of these super creamy—and still healthy—options.