When companies removed Bisphenol A (BPA) from plastics a decade ago, many consumers felt relief, assuming the replacement chemicals were safer. But new research suggests that assumption may be dangerously wrong. A 2024 analysis by Duke University researchers of more than 2,700 plastic additives found that over 150 are classified as cancer-causing, while roughly 90 percent of the additives examined have never been adequately evaluated for cancer risk.

The problem runs deeper than most people realize. As companies swap out problematic chemicals like BPA, which interferes with hormones, they're often replacing them with alternatives that have barely been tested. The Duke researchers found that many of these lesser-known additives appear to disrupt the same biological processes as known cancer-causing chemicals do, raising questions about whether we're simply trading one health risk for another.

What Happens When Plastic Chemicals Enter Your Body?

Scientists are still working to understand exactly how plastic particles and their chemical additives move through, persist in, and exit the human body. But the evidence emerging from laboratory studies is concerning. Melissa Chernick, a toxicologist at Duke University, has been studying how plastic particles and their chemical additives affect zebrafish, which are used in medical research because they share a surprising number of genes with humans.

"We have found altered reproduction, as well as cellular changes in organs like the liver and kidney following dietary exposures to microplastics. This suggests that the additives are leaching out of those plastics and are the cause of these changes," explained Melissa Chernick, toxicologist at Duke University.

Melissa Chernick, Toxicologist at Duke University

In her lab experiments, Chernick and her colleagues expose fish to different types, shapes, and sizes of plastic fragments through direct exposure in water and by feeding them contaminated food. Follow-up experiments using just the chemical additives alone showed they are enough to alter metabolism in fish, suggesting the additives themselves, not just the plastic particles, are driving the harmful effects.

A continuous stream of research suggests that ingesting microplastics, which are particles 5 millimeters or less in size, may contribute to inflammatory bowel disease. Other studies indicate that microplastics can alter how hormones function in the body. A 2019 study estimated that humans may inhale between 74,000 and 121,000 microplastic particles annually.

Why Are Plastic Alternatives Still Untested?

The cycle of chemical substitution without adequate testing is a systemic problem in the plastics industry. When BPA received widespread attention for its hormone-disrupting properties, manufacturers removed it from products like baby bottles and food containers. But many of the substitutes have never been fully tested, and researchers warn they could be just as dangerous.

Chernick and her colleague, Duke researcher Nishad Jayasundara, who leads the project, emphasize that researchers still know little about what happens to these molecules once they're in the human body: where they end up, how long they linger, and whether current lab methods can even measure the effects accurately. The evidence so far is strong enough to warrant additional research, but it is not yet definitive enough to answer basic questions about all the plastic people carry around inside them.

The financial stakes are enormous. A 2023 analysis by Duke researchers estimated that plastic litter and mismanaged waste cost the United States between $436 billion and $1.1 trillion each year, once public health, environmental damage, and economic losses are factored in. In North Carolina alone, the tab tops $56 million a year.

How to Reduce Your Exposure to Plastic Chemicals

While scientists continue to untangle the health effects of plastic additives, experts say it's reasonable for people to treat the evidence as a warning sign and take simple steps to limit exposure where they can. Here are practical ways to reduce your contact with plastic chemicals:

• Avoid heated plastic containers: Don't drink from plastic bottles that have been sitting in a hot car or in the sun. When possible, switch to a reusable metal or glass bottle instead.
• Heat food safely: Reheat leftovers in a glass or ceramic dish first. Even if a plastic container says "microwave safe," it's safer to keep hot food away from plastic.
• Choose glass and metal for storage: Replace plastic cutting boards with wood and use glass or metal containers for storing and carrying food instead of plastic lunch boxes and tubs.
• Minimize plastic contact with food: Look for products with minimal plastic, especially where it touches your food or drink, and buy loose produce instead of items wrapped in plastic when your budget allows.
• Filter your drinking water: Consider using a drinking water filter, such as a reverse osmosis or a granular activated carbon system. These filters can help reduce microplastics in tap water and refilled jugs.
• Reduce synthetic fiber shedding: Choose clothes made of natural fibers like cotton, linen, or hemp, because clothes made from synthetic fibers shed tiny plastic threads. Use a glove or paper towel to clean the dryer's lint trap, then wash your hands afterward.
• Improve indoor air quality: Microplastics are also in indoor air and dust. If possible, use a vacuum with a HEPA filter, and dust with cotton or other natural-fiber cloths instead of microfiber to cut down on particles that settle on floors and surfaces.

These recommendations come from Chernick and Jayasundara, who acknowledge that while scientists don't yet know exactly how plastic particles and additives move through the human body, the precautionary principle suggests taking action now rather than waiting for definitive proof of harm.

The broader challenge remains a broken recycling system. According to the World Health Organization, many plastic items carry the recycling symbol but aren't actually recyclable in most curbside programs. What is accepted for recycling often varies by city or county, depending on what a local contractor can sort, process, or sell at a profit. That patchwork of rules leaves many consumers unsure about what belongs in their recycling bins and what doesn't.

Environmental advocates argue that the combination of single-use plastics flooding the market and a dysfunctional recycling system places the burden for managing all that waste squarely on consumers, while manufacturers and retailers largely avoid responsibility. There is a growing movement underway to shift more of that responsibility away from households and local governments and back to the companies that produce and sell single-use plastic.