You’ve likely seen a label on plastic water bottles for years that says “BPA free.” And you may have thought that’s great, without ever thinking about what it’s being replaced with to make these containers and vessels. And it turns out, the alternatives aren’t much better either.

A new study published in the journalToxicological Sciences reports thatscientists from McGill University examined replacement chemicals used in thermal paper and food packaging, as bisphenol A (BPA) has been banned in many countries worldwide.

Although BPA isn’t banned in the United States, its use is restricted. As the U.S. Food and Drug Administration (FDA) explains, BPA is a “structural component in polycarbonate beverage bottles and also on metal can coatings, which, it adds, “protect the food from directly contacting metal surfaces.” It’s been used in food packaging since the 1960s, and the FDA’s current stance is that “BPA is safe at the current levels occurring in foods.”

As the Environmental Working Group noted, in 2008, the National Toxicology Program of NIH determined that BPA “may pose risks to human development, raising concerns for early puberty, prostate effects, breast cancer, and behavioral impacts from early-life exposures.” It added that “Pregnant women, infants, and young children are most vulnerable to the harmful effects of BPA, although a recent study linked BPA exposures to risk of heart disease, diabetes, and liver toxicity.”

After the 2008 findings were published, companies began replacing BPA with other chemicals, which, according to the McGill researchers, might cause harm than good.

​“‘BPA-free’ is an incredibly misleading label,” Bernard Robaire, the co-senior author of the study, shared in a statement. “It usually means one bisphenol has been swapped for another, and there are than 200 of them. Some may be just as harmful, or even worse. We need to test these compounds before they’re widely adopted, not after.”

The researchers focused their recent work on five BPA substitutes commonly used in thermal labels, including those on meat and produce price stickers for packaged meat, fish, cheese, and produce: BPS (bisphenol S), TGSA, D-8, PF-201, and DBSP. They exposed human ovarian cells (which are essential for hormone and egg production) to seven doses of each chemical, ranging from trace amounts to high concentrations. They discovered that some of these alternatives were clearly toxic.

Of the five chemicals tested, the team found that TGSA had the greatest potential to harm ovarian cells. At the highest doses, TGSA killed roughly 75% of the cells. This was followed by D-8, which also caused major cell death. Both DBSP and PF-201 reduced cell survival but only at the highest concentrations tested. In a small glimmer of good news, BPS, one of the most widely used BPA replacements, showed the lowest toxicity in this experiment.

But cell death wasn’t the only concern. TGSA, D-8, and PF-201 also caused significant fat buildup in the cells. In some instances, the number of fat droplets in ovarian cells increased by than fivefold relative to untreated cells, a change the researchers say could disrupt how these cells function.

The team also examined how the chemicals influence gene activity. They found that TGSA and D-8 altered the activity of than 2,400 genes each, including those involved in DNA repair and stress.

While the team stopped short of concluding that the chemicals are unsafe substitutes, they noted that the findings warrant caution and further studies. “These are major cellular functions,” Robaire said. “Disrupting them doesn’t prove harm in humans, but it gives us a strong signal that these chemicals should be further investigated.”​