The manufacturer of Ziploc bags is facing a class-action lawsuit after a consumer claimed that two of the brand’s key selling points — that the bags are ‘appropriate’ or ‘safe’ for use in the freezer and microwave — were deceptive and increased the risk of exposure to microplastics.

The legal action against Ziploc’s parent company, S.C. Johnson & Son, initiated by plaintiff Linda Cheslow in California, asserts that the company committed a material omission by labeling Ziploc bags as microwave safe and suitable for freezer use. The complaint argues that Ziploc bags and containers are constructed from polyethylene and polypropylene — two materials that release microplastics when subjected to microwaving and freezing.

Consequently, Ziploc bags are claimed to be inherently unsuitable for microwave and freezer use despite their labeling, which has been misleading consumers into believing they can be microwaved and frozen without the risk of microplastics contaminating their food. As stated in the filing, consumers may have unknowingly exposed themselves and their families to hidden microplastics during normal kitchen activities.

Microplastics are tiny plastic particles measuring less than 5 millimeters in diameter, resulting from the degradation of larger plastic items. Ongoing research into the effects of microplastics on human health has linked them to cognitive and behavioral problems, reproductive issues, and cancer, the lawsuit claims.