A chemical being used by some companies as a safer alternative to the controversial plastics hardener bisphenol A (BPA) has shown the same estrogen-disrupting effects in lab tests, researchers said.

The chemical bisphenol S (BPS) disrupted certain responses in rat cells that control key functions such as reproduction, energy metabolism and behavior in a similar manner and extent as BPA, according to a study published in the journal Environmental Health Perspectives.

BPS acts like estrogen hormones and disturbs the body's response to natural estrogen hormones in pituitary cells, the study said.

"It's cause for concern," said Cheryl Watson, the study's co-author and professor at the University of Texas Medical Branch.

"Rats and humans have a lot of cell-system similarities and share the exact same estrogen hormone," Watson said.

Many scientific studies show that compounds that mimic estrogen during the early development of fetuses and children can have adverse health effects, the study said.

The Food and Drug Administration banned BPA in 2012 from use in baby bottles and sippy cups. The chemical is still used as an anti-corrosive in some food and beverage containers.

BPA has been connected to potential heath risks such as diabetes, asthma and altered prostate and was recently linked to a biomarker in children for increased risk of future heart and kidney disease (Greenwire, Jan. 9).

Increased scrutiny and research of BPA led to an effort to find replacement chemicals such as BPS.

BPS is used mainly as a developer in thermal paper products such as sales receipts. Appleton, the leading producer of direct thermal media in North America according to the company's website, swapped out BPA for BPS in 2006.

While Appleton's technical team had not yet looked over the new study, the company's communications manager commented in general about its BPS use.

"The scientific literature about the toxicology of developers used to produce thermal paper has led us to conclude that BPS is a better choice than BPA for overall product safety," said Bill Van Den Brandt, manager of corporate communications at Appleton. "Outside expert opinion supports those conclusions. We welcome ongoing scientific review of BPS and other potential BPA substitutes."

The study noted that the effects of BPS shown in animal models can't necessarily translate to humans, because people have long life spans and don't usually show exposure-based health effects for many years.

But the study said humans have extensive exposure to BPS. The New York State Department of Health recently detected BPS in 97 percent of urine samples from residents of Albany, N.Y., the study noted.

Kurunthachalam Kannan, a research scientist at the Wadsworth Center at New York's Health Department and professor at the State University of New York, and his research team looked at 16 types of paper in the United States, Japan, South Korea and Vietnam. Among their findings, the researchers concluded that people may be absorbing more BPS through their skin than they did BPA when it was used more broadly.

"It's a very interesting study," Kannan said of the findings published today. "BPS seems to be as or more toxic than BPA."

But he added that repetition is needed with that type of study to confirm the results.

Watson argued that it is vital to establish effective pre-screening of any new chemicals or their altered forms that appear to be similar to these hormone-disrupting chemicals before they are put into consumer products.