On October 1, 2026, California’s Department of Toxic Substances Control (DTSC) officially added microplastics to its Candidate Chemicals List under the state’s Safer Consumer Products (SCP) program. The regulation allows DTSC to evaluate consumer products that contain or produce microplastics for potential regulatory action. The agency stated that with their “high mobility and environmental persistence,” microplastics have become widespread in all ecosystems. “They are in dust, indoor air, human food supplies and drinking water” (FPF reported).
DTSC defines microplastics as plastic particles measuring less than 5 millimeters in their longest dimension, without a lower size limit. The listing does not immediately restrict or ban any products or impose new regulatory requirements. Instead, it allows DTSC to identify specific products containing or generating microplastics as Priority Products.
There are two main criteria for selecting Priority Products:
- The potential for exposure to the chemical, in this case, microplastics, associated with the product.
- The potential for that exposure to cause significant or widespread negative impacts on humans, wildlife, or the environment.
The agency also considers the strength of scientific evidence, product life-cycle impacts, vulnerable populations, and whether safer alternatives exist.
Designation as a Priority Product requires separate rulemaking that includes a public comment period, but if applied it could trigger obligations for manufacturers to assess safer alternatives. DTSC has not yet proposed any Priority Products for microplastics.
In an analysis published by Stanford University, researchers described California’s listing as an important legal step toward addressing microplastic pollution, although the human health consequences of exposure remain incompletely understood.
The listing is part of California’s broader efforts to address plastic pollution, beginning with a 2015 ban on microbeads in personal care products and more recently including extended producer responsibility requirements for packaging under SB 54 (FPF reported).
An August 2026 review published in the journal Frontiers in Environmental Science examined California’s evolving approach to microplastic regulation. The researchers, led by Amelia Meyer of Stanford University, described a gradual shift from restrictions on specific products toward broader policies addressing plastic pollution and its potential impacts on human, animal, and environmental health. They highlighted remaining gaps in product coverage, enforcement, and coordination across jurisdictions.
In a Stanford University analysis accompanying the study, the researchers noted the addition of microplastics to the Candidate Chemicals List as an important step toward regulating microplastic pollution, while acknowledging continued uncertainty about the human health effects of exposure. They argued that California’s approach could provide a model for other jurisdictions seeking to address microplastic pollution.
References
California Department of Toxic Substances Control (July 2, 2026). “California finalizes regulation adding microplastics to Candidate Chemicals List.”
California Department of Toxic Substances Control (2026). “Addition to the Candidate Chemicals List: Microplastics.”
Meyer, A. M. (2026). “Microplastic pollution policy and one health: a critical perspective on California legislation as a case study.” Frontiers in Environmental Science. DOI: 10.3389/fenvs.2026.1878679
Stanford Woods Institute for the Environment (2026). “Microplastics and the law explained: What California’s new rule means for plastic policy
