Heat-exposed Plastic Bottles Pose Health Risk: Why you Shouldn’t Drink Water Left in a Hot Car

By Abbas Nazil

As temperatures rise with the approach of summer, staying hydrated becomes increasingly essential.

However, drinking from a plastic water bottle left inside a hot vehicle could pose significant health risks, according to emerging research.

This common habit, often done out of convenience, may inadvertently expose individuals to harmful chemicals that leach into the water when plastic bottles are subjected to heat.

Scientific studies have confirmed that heating plastic water bottles can cause the release of potentially dangerous substances, including Bisphenol A (BPA) and microplastics.

These chemicals can migrate from the plastic into the water, especially when bottles are left inside cars that quickly heat up under the sun.

On an 80-degree Fahrenheit day, the interior of a parked car can soar to 110 degrees in under 30 minutes—conditions sufficient to accelerate chemical leaching.

According to findings published in the International Journal of Environmental Research and Public Health, this heat-induced chemical migration can happen much faster than previously assumed.

The concern is not just the presence of these chemicals, but the health implications they carry. BPA and similar compounds have been linked to a range of health problems, including hormonal imbalances, gastrointestinal issues, and even an increased risk of certain cancers.

Although the exposure from a single heated bottle may be minimal, the cumulative effect of regularly drinking from such bottles amplifies the danger over time.

Plastic bottles are typically made from polyethylene terephthalate (PET), a material that is considered safe under normal conditions.

However, when PET is exposed to high temperatures, its stability degrades, resulting in the release of harmful elements into the contained water.

Experts warn that even short-term exposure to heat—like a quick stop at the grocery store with a bottle left behind—can lead to contamination.

In response to these findings, health experts strongly advise against leaving plastic water bottles in vehicles during warm weather. Instead, safer alternatives such as stainless steel or glass bottles are recommended.

These materials are more resilient to temperature fluctuations and do not release harmful chemicals into drinking water.

For those who need to store water in their cars, using an insulated cooler with ice is another safe strategy to keep water both cool and uncontaminated. Avoiding heat-exposed plastic bottles is a critical step toward safer hydration.