For Debra Berliner, the debate over using plastics in her home is manifested by a BPA-free plastic sippy cup her husband purchased for her 22-month-old son that remains opened but unused in a kitchen cabinet.

“We’re trying to weigh its value and decide whether it has a place in our home, and we haven’t decided,” Berliner said.

The uncertainty in Berliner’s Oakland home was underscored by new research showing that some BPA-free products may be more dangerous than those that include the chemical, bisphenol A.

BPA, a chemical that mimics the hormone estrogen, has been used to harden plastics for more than 40 years but has been banned from baby bottles and children’s products because of growing concerns that it may be linked to a host of health issues.

Now comes news from Oakland’s Center for Environmental Health that some cups labeled BPA-free contain other chemicals that appear to pose an equal if not greater health hazard.

Those chemicals, acting a lot like BPA, have a disruptive effect on the body’s naturally produced hormones, raising the same concerns for the health risks associated with BPA – that exposure to them may lead to cancer, diabetes, reproductive problems, early development and obesity, especially in young children. The research isn’t definitive, but a growing number of studies, mostly done on animals, have raised those suspicions.

BPA-free cups tested

Researchers from the environmental group tested 35 toddler drinking cups labeled BPA-free at two independent labs. The results showed nine of the sippy cups had significant amounts of estrogen-like activity, while seven of those cups had higher activity levels than those made with BPA.

“There’s just an awful lot we don’t know about the chemicals that are in products we use or our kids use every day,” said Caroline Cox, research director of the Center for Environmental Health. “You shouldn’t have to have a Ph.D. in chemistry in order to go shopping. This is a problem that needs to get fixed, but it’s not going to get fixed overnight.”

The study, which was released last week, came on the heels of a published U.S. Food and Drug Administration finding that BPA in low doses does not pose health risks, at least in the rats they studied.

The FDA had declared BPA safe in 2008, but in 2010 modified that position to allow for some “concerns” about the potential health effects of early exposure. In 2012, it banned the chemical in baby bottles and children’s drinking cups, a move that came after manufacturers had stopped using the chemical in those products.

Meanwhile, parents have been purchasing BPA-free products, hoping that they were choosing something safer for their families, and news that those choices may not be any better complicates things for them.

“As a parent, you think, oh great, now what am I supposed to do?” said Mary Brune, an Alameda mother of three children, ages 17 months to 9 years old.

Using glass, stainless steel

But Brune, a longtime environmental activist and a founder of the advocacy group Making Our Milk Safe, said learning that “safe” plastics may not be so safe wasn’t a huge surprise. She said she generally has her children use glasses or glass bottles wrapped in a silicone sleeve for protection, as well as stainless steel canisters with a drinking spout attached. But she admits she sometimes resorts to using plastic for its convenience and durability.

“We travel a lot, so you have to be realistic,” she said. “I try to minimize the damage instead of looking for the thing that’s 100 percent safe. I don’t think, if you’re using plastic, you’ll find anything that’s 100 percent safe.”

Cox said it was the sneaking suspicion that BPA-free didn’t necessarily mean safe from hormonal activity that prompted the study.

Of the BPA-free cups, the worst offenders were those that changed colors when liquid was poured into them, the researchers found. Cox said the test results did not determine which chemicals caused the estrogenic activity, but she suspects they are related to the pigments that cause the colors to change.

Trade group’s response

The American Chemistry Council, a trade group representing North American chemical manufacturers, did not comment directly on the new findings but said the FDA paper published last month, along with previous research, shows that BPA is safe.

“The lead FDA researcher says the results of this recent study ‘both support and extend the conclusion from the U.S. Food and Drug Administration that BPA is safe as currently used,’ ” Steve Hentges, a researcher with the group, said in a statement.

Dr. William Goodson, a breast cancer specialist at San Francisco’s California Pacific Medical Center who researches BPA’s effects on the body, was skeptical of the research that declared low BPA exposure to be safe. He added that it’s difficult to examine just one chemical out of the “soup” of chemicals in any one plastic product.

“The idea you can single out one thing and say, ‘In very low doses, it may not make a difference,’ that’s just not realistic,” he said.

Considering alternatives

While that debate continues, Bay Area stores that sell environmentally sound products for children reported a spike in customers coming in to ask about plastic-free alternatives for their children.

“What I tell parents if they have any question at all about plastic is just to get glass or stainless steel,” said Heather Rider, owner of Monkey Bars, an Alameda store that sells eco-friendly children’s clothing and baby gear. Rider, who has a 21-month-old son, said she stocks only one BPA-free plastic cup.

For Berliner, the BPA-free plastic cup remains unused until more questions about plastic safety are answered.

“These questions are going to be asked again as we continue replacing one nasty chemical with another,” she said. “Something like a bottle or a sippy cup, which is so essential to my child’s sustenance, demands that I ask questions.”

The controversy over BPA-free products

The study: Researchers at the Center for Environmental Health in Oakland tested 35 sippy cups free of the chemical bisphenol A, or BPA, a synthetic form of the hormone estrogen. The study found that nine of the cups leached chemicals with hormonal activity similar to that of BPA, and seven of those cups had greater levels of activity than those made with BPA. Check out the findings here:

The products: First Years Disney Magical color-changing sippy cups (“Cars”; fairies; Minnie Mouse; Mickey Mouse Clubhouse; “Monsters, Inc.,” both the boy and girl versions); Gerber Graduates color-changing cup; CamelBak Hearts spill-proof cup; Born Free Disney Mickey Mouse soft-spout cup.

The alternatives: There are many nonplastic options available by various companies in other materials, such as glass or stainless steel. They can be adapted to be toddler-friendly by placing a silicone sleeve over the glass or attaching a spout.