The internet cheered in December when Trader Joe’s announced it would take meaningful steps towards making its packaging more sustainable. The supermarket chain outlined a plan that included reducing and eliminating excess waste, using materials that could realistically be recycled and avoiding harmful substances. It’s the last part that medical and environmental activists are keeping an eye on.

We’re just beginning to understand some of the short- and long-term risks associated with the chemicals in packaging: obesity, cancer, cardiovascular disease and other health issues. Some consumer advocates say phasing out some of the riskier substances that come into contact with our food is long overdue.

“Avoiding the use of these chemicals of concern in packaging is a great step forward,” said Leonardo Trasande, pediatrician and author of Sicker, Fatter, Poorer: The Urgent Threat of Hormone-Disrupting Chemicals to Our Health and Our Future and What We Can Do About It. “The question is: what replaces these materials?”