Chemical Hazard List

Methodology

First: Cast a Wide Net

I didn't want to write a list based on my opinion or miss anything important that wasn't on my radar. So I started with the major institutions that address toxicants: IARC (the International Agency for Research on Cancer), the National Toxicology Program (NTP), REACH SVHC (the EU's Substances of Very High Concern list), CLP CMR classifications (the EU's harmonized list of Carcinogenic, Mutagenic, and Reprotoxic substances), ATSDR (the Agency for Toxic Substances and Disease Registry), the WHO Global Air Quality Guidelines and 10 Chemicals of Major Public Health Concern lists, Proposition 65, and AB 1200.

Then I expanded to additional sources that catch hazards the institutions haven't yet addressed, that are regulated by industry rather than government, or that are emerging issues with good evidence we should keep an eye out for. For that, I turned to the Six Classes framework (the Green Science Policy Institute's grouping of chemicals of concern by function), DTSC's Candidate Chemicals List, and the EPA’s Drinking Water Contaminant Candidate List 6 that highlights emerging concerns that aren’t formally regulated yet. I also included IFRA, the International Fragrance Association’s list of substances.

Finally, I looked through to see if any substances commonly called out on wellness blogs were noticeably missing or very lightly represented on this list. That included EMFs, blue light, and quats.

Second: Narrow it Down

I only focused on chemicals that were applicable to indoors in homes. I didn't include hazards in automobile manufacturing, dry cleaning, backyard wood construction, or agricultural pesticides. I didn’t even include chemicals in building materials like house siding. They're important, but the scope of Interior Medicine is home products, so I'm keeping it focused.

I only included chemicals that are in current-purchase products only. For example, PBDE flame retardants. Couch and mattress brands aren't using PBDEs anymore; they've moved on to current flame retardants, so the focus is on those instead.

Last, I collapsed categories where subdividing wouldn't change your decision about a product. PFAS is one entry covering roughly 15,000 compounds. Current flame retardants are one entry. Biocides are one entry. Pesticide residues in water are one entry.

Purpose of the List

Several groups draw on similar public lists. OEKO-TEX, for example, builds substances from the EU’s REACH candidate list into its testing limits, and EWG combines many of these toxicity and regulatory databases, plus others, for its product ratings. MADE SAFE screens against a similar list. Each of them applies its list to specific products, through testing, audits, or ingredient review, and then awards a certification, a seal, or a score.

That’s useful. A seal or a score gives you a fast answer while you’re shopping, and certifications like OEKO-TEX test the actual product, which a list can’t do.

I use this list as the foundation for my Material Health Guides. It shows what a chemical is, where it’s found in the home, and which major groups are concerned about it. The guides take the next step and ask what that means for a real product in your home. Is the chemical actually used in that material, or only in older or imported versions? How would you be exposed to it: through your skin, the air, or your food and water? Does heat, wear, or washing release more of it over time? And which certifications test for it, at what limits? That context is what turns a hazard into a rating.

With my approach, instead of a seal or a score, you see the whole chain: the hazard, the lists that flag it, and how I weighed it in a rating. Keeping the list separate means you can always trace a rating back to its sources and check my work.