California Moves to Regulate 1,4-Dioxane in Dish Detergents and Shampoos

Why DTSC’s Priority Product Proposal Matters for Retailers and Brands

California is once again signaling where chemicals regulation is heading.

In a recent proposal, the California Department of Toxic Substances Control (DTSC) announced its intent to list dish detergents and shampoos containing more than 1 ppm of 1,4-Dioxane as Priority Products under the state’s Safer Consumer Products (SCP) program.

While the proposal is not yet final, its implications are immediate—and national.

What’s being proposed?

Under DTSC’s Safer Consumer Products framework, Priority Product designation doesn’t ban a product outright. Instead, it triggers a series of compliance obligations, including:

• Mandatory product notification
• Alternatives Analysis to assess safer substitutes
• Potential reformulation, labeling changes, or supply-chain disclosure
• Increased regulatory scrutiny for manufacturers and importers

The chemical at issue, 1,4-Dioxane, is not intentionally added to most consumer products. Instead, it appears as a byproduct of ethoxylation, a common manufacturing process used to create surfactants found in shampoos and detergents.

Why 1 ppm matters

The proposed 1 ppm threshold is not arbitrary—it closely mirrors limits already established in New York, which enacted one of the most aggressive 1,4-Dioxane standards in the U.S.

That alignment is important.

When two major regulatory states converge on a numeric threshold, the question is no longer if industry will adapt—but how fast.

Between California’s market size and New York’s existing enforcement posture, manufacturers and retailers are increasingly boxed into a single practical option: nationwide compliance at the strictest standard.

Who sets the hard line?

One of the most interesting dynamics to watch is which state drives enforcement first.

• New York already has statutory limits in place.
• California, through DTSC, wields a powerful process-based enforcement tool via Priority Product designation.

Different mechanisms, same destination.

Regardless of which state moves faster or enforces more aggressively, the combined pressure will move the industry—particularly for national retailers that cannot afford state-by-state formulations or SKU fragmentation.

What this means for retailers and brands

For retailers, this proposal reinforces a familiar reality: chemical compliance risk increasingly lives upstream, in product formulation and supplier data—not just on the shelf.

Key impacts include:

• SKU exposure across private label and national brands
• Increased need for ingredient-level visibility, not just SDS summaries
• Greater scrutiny of surfactants and processing aids that historically flew under the radar
• Pressure to validate trace contaminant thresholds, not just intentional ingredients

For brands, especially those selling into California and New York, the message is clear: “unintentional” is no longer a safe regulatory category.

The bigger picture

This proposal fits into a broader regulatory pattern:

• States are targeting byproducts, impurities, and residuals
• Numeric thresholds are replacing qualitative disclosure
• Retailers are becoming de facto compliance gatekeepers

As more states follow California and New York’s lead, the operational burden of chemical compliance will continue shifting from legal interpretation to data accuracy, supplier verification, and proactive classification.

How Smarter Sorting helps

At Smarter Sorting, we help retailers and brands:

• Identify products likely to fall in-scope for emerging state regulations
• Flag ingredients and byproducts tied to Safer Consumer Products risk
• Normalize supplier data across thousands of SKUs
• Route impacted products into the right compliance workflows—before enforcement begins

Because once Priority Product lists are finalized, the hardest work isn’t reading the rule—it’s knowing which products are affected.

Bottom line:
Whether California or New York draws the hardest line first, the direction is set. Dish detergents and shampoos with trace 1,4-Dioxane are officially in regulators’ crosshairs—and the rest of the country is watching closely.

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