Jan. 30, 2008 -- Pouring boiling liquid into reusable water bottles or baby bottles made of polycarbonate plastic causes a much faster release of the estrogen-mimicking chemical bisphenol A, new research shows.
University of Cincinnati researchers reported that exposure to boiling water caused polycarbonate drinking bottles to release bisphenol A (BPA) up to 55 times more rapidly than exposure to cool or temperate water.
The jury is still out on whether BPA exposure poses a health risk to humans, even though the question was the subject of two expert panel reviews in the U.S. last year.
More than 6 billion pounds of bisphenol A are produced and used each year in the manufacture of the resins used to line food cans and in polycarbonate products. Almost everyone has measurable amounts of the man-made chemical in their blood, the CDC says.
It has long been known that BPA can cause genetic damage in lab animals, but it is not clear if the levels of leached BPA from polycarbonate bottles and other products are high enough to pose a threat to humans.
BPA at High Temperatures
Scott M. Belcher, PhD, who led the study team, tells WebMD that while there is little direct evidence that BPA poses a risk to humans, many experts believe that it does.
"The consensus of the scientific community is that there is a clear reason to proceed cautiously," he says.
But Steven G. Hentges, PhD, who is executive director of the American Chemical Council's Polycarbonate/BPA Global Group, disagrees.
Hentges tells WebMD that the finding that BPA leaching accelerates at high liquid temperatures is nothing new, having been reported in numerous previous studies.
"The bisphenol A levels seen under heating conditions are still extraordinarily low and far below levels that have been determined to be safe by government bodies," he says.
The popularity of reusable, plastic polycarbonate drinking bottles has grown with rising concerns about the environmental impact of disposable plastic bottles.
Plastic water and soda bottles manufactured for one-time use are not made with polycarbonate plastic. But many baby bottles and those hard water bottles sold in outdoor and athletic stores are.
Same Levels in New and Old Bottles
Belcher collected used polycarbonate water bottles from his local climbing gym and purchased new ones from a nearby outdoor activities store.
All the bottles were subjected to seven days of testing designed to simulate normal use during backpacking and camping conditions.
Whether they were new or used, the bottles released the same average amount of bisphenol A at the same rate when exposed to cool or temperate water.
"There is some thinking that the longer a bottle is used the more BPA it releases, but that isn't what we found," Belcher says.
But much higher levels of bisphenol A were released when the bottles were briefly exposed to boiling water. The rate of release after exposure to boiling water ranged from 8 to 32 nanograms per hour, compared with a range of 0.2 to 0.8 nanograms per hour under room-temperature conditions.
And the speed of release was 15 to 55 times faster, Belcher says.
He adds that the findings have made him reassess his own habits.
"I don't put hot tea or hot water in these bottles when I'm climbing anymore," he says. "And I have retired my polycarbonate French-press coffeemaker."
What the Experts Say
The two expert panels that recently weighed in on the safety of bisphenol A reached different conclusions.
The National Toxicology Program's Center for the Evaluation of Risks to Human Reproduction (CERHR) convened a 12-member panel made up of government and non-government scientists to review the scientific evidence.
The group concluded that bisphenol A exposure levels for most Americans were well within the Environmental Protection Agency's standards and found no major health risks associated with exposure.
The panel did express "some concern" that the chemical could cause behavioral and neurological problems in developing fetuses and young children, however.
Another panel made up of 38 researchers who have studied BPA concluded that levels of the chemical seen in humans are higher than those that caused adverse effects in animal studies.
The group also expressed confidence that even low doses of BPA can have biological effects.
Belcher, who served on the latter panel, says the group concluded that there was good reason for concern that bisphenol A can cause harm to humans at routine exposure levels.
Hentges says the panel was far from objective and their findings contradict those of other experts around the world.
"The very extensive research that has been done supports the safety of bisphenol A," he says. "That is the consensus of experts worldwide who have no stake in this."
Do not heat liquids or foods in containers that do or might contain BPA, as heat increases the amount of BPA that leaches into food. BPA-containing plastics typically have the recycling code "7" on the bottom. Consider using fresh and frozen foods instead of canned foods.Is it safe to put hot liquid in a plastic bottle? ›
Plastic water bottles are made from polyethylene terephthalate. Whenever a bottle is heated, the material releases the chemicals bisphenol and antimony, also known as BPA. There have been studies to suggest that this chemical can cause adverse health effects in children.At what temperature does plastic release BPA? ›
Higher temperature at 70 °C induced significant release of Sb and BPA.Does heating BPA free plastic release toxic? ›
Still, studies have shown that even BPA-free plastics can release other hormone-disrupting chemicals like phthalates, or BPA alternatives like bisphenol S and F (BPS and BPF), into foods when microwaved ( 12 , 13 , 14 , 15 ).At what temperature do plastic bottles leach? ›
Antimony can be leached from water bottles made of PET plastics. The rate of leaching is low at a storage temperature of 25°C. However, at temperatures of 50°C and above, antimony release can occur very rapidly.What temperature is too hot for plastic water bottles? ›
At 158°F (70°C) (about the temperature in a car on a hot summer day), levels of antimony in water increased significantly to 38.5 ng /L. Levels of antimony in one of the sixteen water bottles increased to 2604 ng/L.Is it OK to put hot water in BPA free plastic? ›
No, boiling water does not release toxic chemicals from the plastic of your Nalgene water bottle. They are made from a safer type of plastic called Tritan plastic. * Tritan is a BPA-free plastic — it is not manufactured with bisphenol A (BPA) or other bisphenol compounds, such as bisphenol S (BPS).Does plastic release toxins when heated? ›
Don't heat up plastic.
Heating up plastics can increase the rate through which chemicals leach out, so try to avoid putting them in the microwave or dishwasher. Even leaving plastic containers out in a hot car could increase the release of concerning chemicals, says Vandenberg.
Tips for safe plastic use
Doctors don't recommend heating food in plastic containers because heat increases the chances that chemicals will seep out of the container and into your food. Choose to heat food in glass or metal containers instead. Choose products marked “BPA-free” if you can.
30 (HealthDay News) -- Exposing plastic bottles to boiling water can release a potentially harmful chemical 55 times faster than normal, new research suggests. Bisphenol A (BPA) is found in the plastics that make up water bottles, baby bottles, and other food and drink packaging.
Fumes from heated metal and burning plastic products can cause flu-like illnesses in people and animals. People who weld metals at work are at risk, as are those who overheat PTFE (Teflon)-coated cookware. Getting away from the source of the fumes is the most important treatment.How does temperature affect BPA? ›
An increase in the content of BPA, up to the temperature of 28 °C, is observed; a further increase in temperature does not increase the amount of this compound released into the water from the material.Does BPA leach at room temperature? ›
Once these BPA-containing plastics contact food or liquids, the BPA slowly leaches out. If the food or drink is hot, the BPA migrates to the food 55 times faster than at room temperature, according to a 2008 University of Cincinnati study.