While residents of Sub-Saharan Africa and Flint, Mich., strive for access to clean drinking water, some in the West are more concerned with the containers which house this liquid. While this could be seen as a First World problem, our focus here is not on affluent privilege but on how factual such worries are. We will examine if plastic water bottles release unsafe levels of chemicals when they are heated, cooled, or reused.

There have been a myriad of such claims on the Internet for at least 15 years and they often contain a nugget of truth, but leave out key facts while leaping to unfounded conclusions. The nuggets include a factoid about heat often releasing chemicals, usually identified in forwarded chain mail as dioxins. This is sometimes accompanied with calls that the bottles be banned. Some plastics do contain levels of chemicals that could be dangerous if released or which seep into containers when heated.

But plastic water bottles are usually made from polyethylene terephthalate (PET), which does not have those qualities. Water can be safely stored in them, whereas gasoline probably could not be and carbolic acid certainly couldn’t be. That’s why manufactures of containers for water, gasoline, and carbolic acid all utilize different types of plastics for their products. Because they are made from polyethylene terephthalate, water bottles will not become dangerous due to heating, freezing, or reuse.

If concerned about safety, remember to use products for their intended use. There are multitudinous plastics and what each is used for is dependent on their characteristics. The American Chemical Council has gone on record that there is no science to support the claim that PET bottles will release dioxins when frozen or heated. It stated, “Dioxins can only be formed at temperatures well above 700 degrees…and there is no scientific basis for expecting dioxins to be present in plastic food or beverage containers.” So unless you live on Venus, don’t worry about leaving bottled water in your car on a summer day.

Another claim is that the plastics additive diethylhydroxylamine may seep into whatever liquid a plastic container is carrying. However, this additive is not used in plastic water bottles, nor is it created through the breakdown of such bottles. And even if it did, the agent has been approved by the FDA for food-contact applications.

Addressing these concerns, civil engineer and biologist Rolf Halden noted the irony of persons being more concerned about the containers than the product inside. “Many people do not feel comfortable drinking tap water, so they buy bottled water instead,” Dr. Halden said. “The truth is that city water is much more highly regulated and monitored for quality. Bottled water can legally contain many things we would not tolerate in municipal drinking water.”

He noted that safety can usually be assured by following warning labels and directions. For example, heat can cause some plastics to release chemicals, which is why there are cautions on certain drinking straws to refrain from using them with hot beverages.

“If you put that straw into a boiling cup of hot coffee, you have hot water extraction going on and chemicals in the straw are being extracted,” Halden explained.

Maybe that’s why I’ve never seen anyone drink coffee with a straw.