Ziploc Bag Class Action Lawsuit Claims Microwavable Bags Release Dangerous Levels of Microplastics

Plastic bags marketed as “microwave safe” and “suitable for freezer use” can release dangerous microplastics when used as their packaging recommends, lawsuit alleges.

A California woman has filed a class action lawsuit alleging that certain Ziploc bags are made with polyethylene and polypropylene, which can release dangerous microplastics under extreme temperatures, such as those found in microwave ovens and freezers.

The complaint (PDF) was brought by Linda Cheslow in the U.S. District Court for the Northern District of California on April 25, naming S.C. Johnson & Son, Inc. as the sole defendant.

S.C. Johnson has owned the Ziploc brand of plastic bags since 1998, when it acquired DowBrands. Ziploc bags are reclosable storage bags, typically made from polyethylene, which is a common type of food-grade plastic. However, polyethylene has been known to leach chemicals and microplastics under certain circumstances, including stress and heat.

Microplastics are small fragments of plastic, under 5 millimeters in length. In recent years, they have been found throughout people’s bodies, including human testicles and human brains. They are known to affect the endocrine system and interfere with the gut microbiome, also damaging DNA, which can lead to various other illnesses, including cancer and cardiovascular disease.

According to Cheslow’s lawsuit, Ziploc bags are marketed as “microwave safe” and “suitable for freezer use,” which prompted her to purchase them sometime in 2024.

However, since the bags are made from polyethylene and polypropylene, neither of these claims are factual, Cheslow says, claiming that the plastic materials can break down under microwave heat, while freezing the bags causes undue stress to the plastic. In both instances microplastics could then be released by the bags, the complaint points out.

As a result of these occurrences, Cheslow indicates that she and other individuals have exposed themselves and their families to undisclosed amounts of microplastics by using Ziploc bags merely as they are advertised by the manufacturer.

In her complaint, Cheslow mentions a handful of Ziploc products by name, including:

• Ziploc Freezer Bags Pint/Small, Freezer Bags Quart/Medium and Freezer Bags Gallon/Large
• Ziploc Slider Freezer Bags Quart/Medium
• Ziploc Slider Freezer Gallon/Large Bags
• Ziploc Slider Storage Bags Quart/Medium
• Ziploc Slider Storage Bags Gallon/Large
• Ziploc Containers

“Defendant affirmatively represents that the Products are ‘Microwave Safe,’ and/or fit for the ‘Freezer,’ leading consumers to believe they are fit to be microwaved and frozen without risk of microplastics leaching into their food,” the lawsuit states. “At the same time, Defendant omits material information that the Products release microplastics when microwaved and frozen as intended, directed and instructed.”

Cheslow raises allegations of violation of California’s Unfair Competition Law, False Advertising Law and Consumers Legal Remedies Act, as well as unjust enrichment.

She is seeking certification of class action status for her lawsuit, including a subclass for California residents, as well as declaratory relief, injunction, damages, restitution, disgorgement and punitive penalties from S.C. Johnson.