Kids may be anxious about finding a seat on the school bus or meeting a new teacher as they head back to school, but some parents have new worries: A recent report from the Center for Health, Environment & Justice shows that many school supplies are laden with chemicals deemed too toxic for toys.

NEWS: Flame Retardants: Do We Need to Worry?

Vinyl lunchboxes, backpacks and even 3-ring binders were among the 75 percent of supplies tested by an independent laboratory for the CHEJ that were found to have

elevated levels of the endocrine disruptors.

Research has linked phthalates, which are used to soften plastic, to birth defects, obesity, asthma and infertility, among other ailments. Some were banned in toys in 2008.

NEWS: Drug Coatings Can Contain Problematic Chemicals

"It's amazing that we can have a ban of phthalates in children's toys, but that high levels of these chemicals are still being used in children's back-to-school supplies at a rate that far exceeds the ban in toys," Katie Rojas-Jahn, coalition coordinator for the Minnesota-based Healthy Legacy campaign and a program associate at the Institute for Agriculture and Trade Policy, told MinnPost.

The organization tested 20 products, and found phthalates in 16 of them — though none of them contained any mention of phthalates on their labels. Many of the products tested at levels far beyond what's considered safe for toys: the Amazing Spiderman Backpack, for example, would be over 52 times the limit set for toys.

NEWS: Baby Products Loaded With Toxins

"If I were a parent, I think the first thing you have to realize is that you can't control all your exposure, so when you do have the opportunity to control it, as is the case here, by simply avoiding these products, you should take advantage of that," Tom Zoeller, an expert in endocrine disruptors and former National Institute of Environmental Health Sciences (NIEHS) researcher, told Forbes.

"At some point we have to begin to have a regulatory system that uses measurements that will predict a chemical's impact on chronic disease because most of it is set up in either fetal stages or in early childhood development. And yet there's no real effort to try to do that — to test chemicals for their ability to impact public health in a matter that’s relevant to public health today."

In the meantime, the CHEJ has a guide to PVC-free products. And some argue that the concern is overblown: the American Council on Science and Health, a group known for defending chemical use, says there's no evidence the products cause harm, TIME reports.

Photo: iStockPhoto