California DTSC Adds Microplastics to Its Candidate Chemicals List

On June 18, 2026, the California Office of Administrative Law approved the California Department of Toxic Substances Control’s (DTSC’s) final regulation adding microplastics to the Candidate Chemicals List.  The regulation will be effective starting October 1, 2026. 

Under the regulation, microplastics are defined 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.”  DTSC’s Microplastics in Consumer Products webpage indicates that this definition would include (1) primary microplastics, which are manufactured and intentionally added to products (e.g., microbeads in personal-care products) and (2) secondary microplastics, which are generated from the degradation of plastic products such as plastic bags or water bottles.

The Candidate Chemicals List is part of DTSC’s Safer Consumer Products Program. The addition of microplastics to the Candidate Chemicals List does not by itself create new regulatory requirements. However, microplastics must be added to that list before DTSC can regulate Priority Products that contain or generate microplastics. At this time, DTSC has not proposed the regulation of any Priority Products that contain or generate microplastics.

More information on DTSC’s addition of microplastics to its Candidate Chemicals List can be found here, and more information on DTSC’s Safer Consumer Products Program can be found here.