2026-08-19 · Testing · 5 min read

From shopping cart to certificate of merit: how we test

Anyone can claim a product is contaminated. The difference between an accusation and a finding is the paper trail. Ours is built so that every claim we make could be handed to a skeptical opposing counsel — because eventually, it will be.

Step 1 — Selection, by published criteria

We don't test at random, and we don't test on vibes. Candidate products combine four factors: an ingredient category with a known contamination pathway (cocoa, leafy greens, rice, root crops), a large serving size (more material per dose means more exposure per dose), high sales volume (a violation that reaches millions of people matters more than one that reaches dozens), and the absence of an existing Proposition 65 warning. The criteria are published so nobody has to guess why a product ended up on our bench.

Step 2 — A purchase like any consumer's

We buy the product at retail, the same way you would, and we preserve everything: the order confirmation, the invoice, the delivery record, photographs of the product as received, the lot number. This is the start of the chain of custody. If a company later argues "that's not our product" or "that's not how consumers buy it," the record answers.

Step 3 — An accredited laboratory, validated methods

Samples go to an ISO/IEC 17025-accredited laboratory — the same accreditation standard industry relies on for its own quality programs. Heavy-metals panels run on inductively coupled plasma mass spectrometry (ICP-MS) under validated AOAC methods. We use independent commercial laboratories, not an in-house bench, so no one has to take our word for the numbers: the certificate of analysis is the laboratory's own document, and we publish it.

Step 4 — Exposure math, using the state's own numbers

A concentration on a lab report means nothing to a consumer until it's converted to exposure. The math is deliberately simple: micrograms of the chemical per gram of product, multiplied by the grams in the label's own serving size. That per-serving exposure is compared to California's published safe-harbor level — for lead, a Maximum Allowable Dose Level of 0.5 micrograms per day for reproductive harm. Our first test measured 0.772 micrograms of lead in one labeled serving of a top-selling plant protein powder: 154% of the safe harbor, from following the label's own instructions.

Step 5 — An expert signs their name

Before any enforcement step, a credentialed quality and regulatory expert reviews the purchase records, the laboratory data, and the exposure calculation, and signs an attestation that the data support the alleged violation. California law requires this substance for private enforcement: a 60-day notice must be accompanied by a certificate of merit attesting that the person executing it consulted with someone with relevant expertise and believes there is a reasonable and meritorious basis for the action. It is a real check, with a real signature.

Step 6 — Enforcement, in public

If the numbers support it, a 60-day notice is served on the company — and on the California Attorney General, every county District Attorney, and certain city attorneys. That service list is the point: private enforcement under Proposition 65 is designed to happen in front of public prosecutors, who can take over the case or object to a weak one. When we serve a notice, we publish the underlying documents here the same day.

That's the whole machine. No anonymous allegations, no cherry-picked screenshots — a chain of documents that starts with a shopping cart and ends with a signature.

This article is educational information about CSRC's methodology and California law, not legal or medical advice. Test results describe specific purchased samples and lots; results may vary between lots. © 2026 Consumer Safety Research Center Inc.