• On July 2, 2026, California’s Department of Toxic Substances Control (DTSC) announced its finalized rulemaking adding microplastics to the Candidate Chemicals List.
  • This rule defines microplastics as “plastics that are less than 5 millimeters (mm) in their longest dimension, inclusive of those materials that are intentionally manufactured at those dimensions or are generated by the fragmentation of larger plastics.” Several trade associations expressed concern over this definition, pointing out how it could include secondary microplastics, which are generated when larger microplastics break down.
  • A DTSC report marked that food contact articles such as plastic wrappers and single-use tea bags as potential sources of secondary microplastics. The report requested information on potential non-plastic alternatives to these articles.
  • DTSC has also released a Technical Document explaining some of the department’s scientific basis for the rulemaking. The document claims that microplastics are found in environmental sources like water and dust, but also food, industrial coatings, cosmetics, and many other types of products. DTSC Director Katherine Butler called the rulemaking “a critical step” to address widespread environmental contaminants.
  • Despite receiving 189 comments on the proposed rule, DTSC finalized the rulemaking unchanged.
  • While the rulemaking alone does not impose new obligations on manufacturers or retailers, it will initiate agency review to determine whether microplastics should be regulated as a priority chemical through a separate rulemaking process.
  • The Candidate Chemical list also overlaps with California’s AB 1200, which requires manufacturers to disclose candidate chemicals intentionally added to cookware. Manufacturers must print this information on the product label and direct the consumer to an online disclosure. Because the rulemaking regulates plastics from “fragmentation of larger plastics,” it is currently unclear how manufacturers should determine whether a microplastic particle is “intentionally added.”
  • Keller & Heckman will continue to monitor microplastic law developments.