What you may have heard
Heating plastic in the microwave or freezing plastic releases various harmful chemicals that may cause cancer.
What science tells us
Freezing tends to work against the release of chemicals. The Johns Hopkins Bloomberg School of Public Health stated, “Chemicals do not diffuse as readily in cold temperatures, which would limit the chemical release” (LAT). This means that freezing any type of plastic container poses no cancer risks.
Diethylhexyl adipate (DEHA) is found in some plastics and may be released when the container is heated (LAT). It is possible that substances used in the manufacturing process of plastics, such as DEHA, may leak into food during the heating process. But the FDA imposes strict regulations on plastic containers labeled as “microwave safe” (FDA).
However, the Environmental Protection Agency has said that DEHA “cannot reasonably be anticipated to cause cancer; immunotoxicity; gene mutations; liver, kidney, reproductive or developmental toxicity; or other serious or irreversible chronic health effects” (Fillon et al.).
Laboratory Evidence/Supporting Evidence
There is no laboratory evidence that microwaving or freezing plastics increases your risk of cancer.
IARC Carcinogen Classification: Group 3 (Not classifiable as to its carcinogenicity to humans: Di(2-ethylhexyl) adipate)
How to reduce your risk
The best way to reduce your risk is to microwave food in heat-resistant glass or ceramics that are labeled as microwave safe.
Levels of DEHA found in plastics have not been conclusively shown to be carcinogenic (cancer causing). However, plastic utensils and containers vary in their chemical makeup, and ongoing research may find links with specific chemicals and cancer.
Learn More From These Trusted Sources
Food & Drug Administration (FDA): 5 tips for safe microwave oven use
American Society of Clinical Oncology: Microwaves and cancer
World Health Organization (WHO): Microwave ovens
Fillon et al.: BPA and the Difficulty of Proving Environmental Cancer Risks
Los Angeles Times: Heat’s on Plastic Containers
Published: January 26, 2022
Verified/updated: August 22, 2022