By now, most people know the Earth is overwhelmed with plastic. It drifts in our oceans and swims in our drinking water, piling up in landfills to last for generations. To combat the plastic pollution, you do what you can, taking reusable bags to the grocery store and not using straws. But a new report may make you rethink your plastic consumption completely.

Norwegian researchers studied many everyday items — from yogurt cups to bath sponges — and found toxic chemicals in three-quarters of them.

"The problem is that plastics are made of a complex chemical cocktail, so we often don't know exactly what substances are in the products we use. For most of the thousands of chemicals, we have no way to tell whether they are safe or not," co-author Martin Wagner, a biologist at the Norwegian University of Science and Technology, said in a statement.

"This is because, practically speaking, it's impossible to trace all of these compounds. And manufacturers may or may not know the ingredients of their products, but even if they know, they are not required to disclose this information."

It's not easy to isolate the chemicals or the specific plastics. There are more than 5,000 types of plastic, with thousands of types of chemicals used to make them. Researchers are aware of more than 4,000 chemicals used just in plastic food packaging, so the overall number of chemicals is likely much greater.

For the study, which was published in Environmental Science and Technology, the researchers found more than 1,400 substances in the plastics they studied, but were only able to identify 260 of them. They found that 60% of the plastic products had general toxicity; 40% produced oxidative stress (which is thought to be linked to cancer, diabetes and heart disease); and 30% had endocrine-disrupting effects (which are linked to cancer and developmental issues).

Pinpointing harmful plastics

Plastic recycling symbols Some plastics are safer bets than others. (Photo: Stakes/Shutterstock)

Of the plastics they studied, the team found that the chemicals in polyvinyl chloride (PVC, usually marked as 3s in recycling codes) and polyurethane (PUR) were the most toxic. By comparison, polyethylene terephthalate (PET, usually marked as 1s) and high-density polyethylene (HDPE, usually marked as 2s) were less toxic.

"Plastics contain chemicals that trigger negative effects in a culture dish. Even though we do not know whether this will affect our health, such chemicals simply shouldn't be in plastics in the first place," Wagner says.

And researchers point out that it's not easy to know what you're looking for. For example, they tested four different yogurt containers and found toxic chemicals in just two of them.

Although this sounds disheartening for people who want to make safe, informed shopping decisions, the researchers have some helpful advice. The first, is obviously, is to cut back on plastic use. Try to avoid PVC, which is labeled with recycling code #3, and plastics labeled as #7, because it's not clear what type of plastics they are made from.

They also suggest working with retailers and companies to ask what materials and chemicals are in their plastic products.

"We need to avoid demonizing plastics," Wagner says. "But given that we live in the plastic age, we need to make sure they don't affect our health."

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.

How dangerous are chemicals in plastic consumer products?
Researchers found that three out of four everyday plastic items contain toxins.