Viral Warning: Don't Drink Bottled Water Left in Car

Does water from disposable plastic bottles pose a cancer threat?

Mineral water production, bottling plant
Hans-Peter Merten/Stone/Getty Images

A forwarded message circulating online warns consumers not to drink bottled water that has been sitting in a warm car for any length of time because, supposedly, the heat causes cancer-producing toxins to "leak" from the plastic into the water. How accurate is it?

Description: Email rumor / Viral text
Circulating since: April 2007
Status: False as written / Scientific research is ongoing

2013 Example of the Rumor

As posted on Facebook, May 4, 2013:

Plastic Bottled Water DIOXIN Danger
Bottled water in your car is very dangerous! On the Ellen show, Sheryl Crow said that this is what caused her breast cancer. It has been identified as the most common cause of the high levels of dioxin in breast cancer tissue..
Sheryl Crow’s oncologist told her: women should not drink bottled water that has been left in a car. The heat reacts with the chemicals in the plastic of the bottle which releases dioxin into the water. Dioxin is a toxin increasingly found in breast cancer tissue. So please be careful and do not drink bottled water that has been left in a car.
Pass this on to all the women in your life. This information is the kind we need to know that just might save us! Use a stainless steel canteen or a glass bottle instead of plastic!
This information is also being circulated at Walter Reed Army Medical Center ... No plastic containers in microwaves. No plastic water bottles in freezers. No plastic wrap in microwaves.
Dioxin chemical causes cancer, especially breast cancer. Dioxins are highly poisonous to cells in our bodies. Don’t freeze plastic bottles with water in them as this releases dioxins from the plastic. Recently the Wellness Program Manager at Castle Hospital, was on a TV program to explain this health hazard.
He talked about dioxins and how bad they are for us. He said that we should not be heating food in the microwave using plastic containers..... This especially applies to foods that contain fat.
He said that the combination of fat, high heat and plastic releases dioxin into the food.
Instead, he recommends using glass, such as Pyrex or ceramic containers for heating food... You get the same result, but without the dioxin.. So, such things as TV dinners, instant soups, etc., should be removed from their containers and heated in something else.
Paper isn’t bad but you don’t know what is in the paper. It’s safer to use tempered glass, such as Pyrex, etc.
He reminded us that a while ago some of the fast food restaurants moved away from the styrene foam containers to paper. The dioxin problem is one of the reasons....
Also, he pointed out that plastic wrap, such as Cling film, is just as dangerous when placed over foods to be cooked in the microwave. As the food is nuked, the high heat causes poisonous toxins to actually melt out of the plastic wrap and drip into the food. Cover food with a paper towel instead.
This is an article that should be share to anyone important in your life!

2007 Example of the Rumor

Subj: Drinking Bottled Water Kept in Car
...a friend whose mother recently got diagnosed with breast cancer. The doctor told her women should not drink bottled water that has been left in a car. The doctor said that the heat and the plastic of the bottle have certain chemicals that can lead to breast cancer. So please be careful and do not drink that water bottle that has been left in a car and pass this on to all the women in your life.
This information is the kind we need to know and be aware and just might save us!!!!
*The heats causes toxins from the plastic to leak into the water and they have found these toxins in breast tissue. Use a stainless steel canteen or a glass bottle when you can*!

Note: Newer variants of the above warning reiterate a previously circulated claim that microwaving food in plastic containers and/or plastic wrap releases dioxin into the food. 

Analysis: False as Written

Analysis: False as written, though research into potential health hazards associated with disposable water bottles is ongoing (see updates at the bottom of this page).

Plastic bottles of the type used for packaging commercially marketed drinking water in the U.S. are regulated by the FDA as "food contact substances" and held to the same safety standards as food additives. This means, among other things, that the FDA reviews test data on the safety of the plastics used in disposable water bottles—including the potential for hazardous chemicals to leaching or "migrate" from the plastic into the water—and has thus far established that they pose no significant risk to human health. The water itself is also tested and required to meet basic quality standards similar to those set by the Environmental Protection Agency for public drinking water.

Disposable vs. Reusable

It's important to note that the plastic used in the manufacture of pre-packaged, disposable water bottles is different from the plastics believed to pose a human health threat in other applications such as baby bottles, plastic children's toys, and reusable sports water bottles. Disposable water bottles do not contain bisphenol A (BPA), for example, about which safety concerns have been raised.

That's not to say that water sold in plastic bottles is one hundred percent free of all contaminants, or that chemical leaching from plastics to liquid never takes place. Studies completed on water bottled in FDA-approved polyethylene terephthalate (PET), for example, did find that trace amounts of potentially hazardous substances had apparently migrated from the plastic into the water. The important point to take away, however, is that those amounts were minuscule, and well within the human safety limits set by FDA and EPA regulators.

Germs a Greater Concern?

According to Dr. Rolf Halden of the Johns Hopkins Bloomberg School of Public Health, consumers face a much greater risk from potential exposure to microbial contaminants in bottled water—germs, to you and me—than from chemical ones. For that reason, most experts suggest not refilling or reusing empty bottles.

It should also be noted that the plastics used in the manufacturer of reusable water bottles vary in composition and quality and may be more susceptible to chemical leaching than the disposable type.

Regarding Sheryl Crow

Some versions of this warning contain the additional claim that musician Sheryl Crow announced during a pre-2008 appearance on the Ellen Degeneres TV show that she got breast cancer as a result of drinking bottled water. While it's true that Crow has discussed her bout with cancer on Degeneres' show more than once and reportedly cautioned viewers against drinking water from heated plastic bottles during one of those appearances, I've found no evidence confirming that she explicitly blamed her own cancer on water bottles. Citing advice from her own nutritionist, Crow did issue a warning against drinking water from heated bottles in a September 2006 statement on her website, but, again, did not claim it was the cause of her own illness.


A 2009 German study on chemical leaching raised concerns about the safety of disposable water bottles, which are currently regarded as safe by the FDA and other government health agencies. Researchers in Germany found evidence of a man-made estrogen-like compound leaching into water packaged in polyethylene terephthalate (PET) bottles. This type of substance, known as an "endocrine disruptor," has the potential to interfere with estrogen and other reproductive hormones in the human body. Please note that the authors of the study conclude by saying that more research is required to determine whether, and to what degree, this poses an actual health risk to human beings.

A 2014 joint Chinese and University of Florida study on water stored in PET bottles for a relatively long period of time (four weeks) at temperatures up to 158 degrees Fahrenheit found that levels of the chemicals BPA and antimony, a carcinogen, gradually increased. Though only one brand of the 16 tested yielded amounts of these chemicals exceeding EPA safety standards, researchers said more testing is needed to ensure the safety of the products.

Sources and Further Reading