Decoded Korea

Until August 2025, Korean chemical law kept a single list of toxic substances. A mixture became a toxic substance once a listed ingredient passed a set concentration, and that concentration was low enough to catch everyday products. Under the old rules, a mixture containing 0.1 percent benzene counted as toxic, which put gasoline, at roughly 0.7 percent benzene, under the same controls as far more dangerous materials. On August 7, 2025, the revised Act on the Registration and Evaluation of Chemicals (K-REACH) replaced that single category with three hazard categories, each with its own concentration threshold for mixtures. We counted every designation in the current public data to see where the substances ended up. What the three categories mean Human acute hazard covers substances that can harm health after a single or short exposure. Human chronic hazard covers harm from repeated exposure, or harm that shows up after a latency period. Ecological hazard covers harm to aquatic or...

Chemical substance management and cosmetics regulation are separate systems in Korea. K-REACH sits with the Ministry of Environment and asks whether a substance is hazardous to handle, persistent, bioaccumulative, or requires registration above a volume threshold. The Cosmetics Act sits with the Ministry of Food and Drug Safety and asks whether a substance is safe on skin. We hold both datasets, 47,041 chemical substances and 21,796 cosmetic ingredients. Matching them on CAS number shows where the two systems overlap and, more usefully, where one of them is silent. The shape of the overlap Of the 41,674 K-REACH substances carrying a CAS number, 3,128 CAS values also appear in cosmetic ingredient records. That maps to 3,129 chemical substance records and 3,997 cosmetic ingredient records, the mismatch coming from cosmetic entries that list several CAS numbers and from three cases where one CAS appears against more than one substance record. Cross-tabulating by whether each syste...

Lead, arsenic, cadmium, and mercury are the four heavy metals that regulators worry about most — in food, in water, in cosmetics, and in industrial chemicals. They get grouped together in headlines as "toxic heavy metals," as if they were interchangeable. In the regulatory data, they are not. Each is dangerous in its own specific way, and the way a chemical database classifies them shows the difference clearly. We queried the K-REACH database, which holds 47,517 chemical substances registered in Korea, each carrying nine regulatory flags. Searching for the compounds of these four metals returns hundreds of entries, and the pattern of flags tells you something the "toxic heavy metal" label hides: three of the four are dominated by cancer risk, and one is not. The four metals by the numbers Counting the registered compounds of each metal and their flags: Metal Compounds Toxic CMR CMR share Lead 180 159 113 63% Cadmium 107 105 65 61% Arsenic 22 22 17...

If you handle chemical compliance for products entering Korea, the question is rarely "is this chemical dangerous." It is "how does Korea classify it, is it registered, and does it carry a GHS label requirement." Those answers live in K-REACH — Korea's Act on Registration and Evaluation of Chemical Substances — and in the GHS classifications maintained alongside it. The K-REACH Chemical Substance API exposes 47,517 registered substances, each with nine regulatory flags, plus GHS hazard data, through a single JSON interface. Like our cosmetics API, the data is Korean in origin, but the fields a chemical compliance workflow uses — CAS number, English name, the hazard flags, GHS pictogram codes, UN numbers — come back in English or in international standard form. A non-Korean-speaking analyst can run the whole thing. This post walks through five real queries and what each one answers. The nine flags Every substance in the database carries nine boolean regulato...

PFAS — per- and polyfluoroalkyl substances, the "forever chemicals" — are the target of the largest chemical restriction in EU history. A proposal to limit more than 10,000 of them at once is moving through the EU system, with a decision expected in 2026. Several US states have already banned them from cosmetics, textiles, and furniture. Korea's chemical database, K-REACH, registers 147 PFAS. None carry the "prohibited" flag. Eighteen are classified as persistent organic pollutants. The rest — about 129 — are registered with no hazard classification at all. What PFAS are PFAS are a family of synthetic chemicals built around carbon-fluorine bonds, among the strongest in chemistry. That bond is why they resist heat, water, and oil, and why they are used in non-stick coatings, waterproof fabrics, food packaging, and firefighting foam. It is also why they do not break down — they persist in water, soil, and human blood for years. Hence "forever chemicals....

Korea's chemical substance management system, K-REACH, tracks over 47,000 registered substances. Each one carries up to 9 regulatory flags — toxic, restricted, prohibited, priority management, CMR, accident preparedness, registration required, persistent organic pollutant, and Rotterdam Convention. Of those 47,000+, only 97 carry the "prohibited" flag. That is 0.2% of the database. These are substances where handling itself is banned in Korea — manufacturing, import, and use are all prohibited. We pulled the full list to see what Korea considers dangerous enough to ban entirely. What the 97 look like The 97 prohibited substances fall into a few recognizable groups. Banned pesticides — the largest group About half the list consists of pesticides that were widely used in agriculture before being phased out globally. Aldrin, Dieldrin, Endrin, Heptachlor, Chlordan, Endosulfan, Paraquat, Parathion — names that show up in environmental science textbooks. Most of these ar...

Korea's chemical substance database tracks over 47,000 substances. Each one can carry up to 9 regulatory flags — toxic, restricted, prohibited, priority management, accident preparedness, CMR (carcinogenic/mutagenic/reprotoxic), registration required, persistent organic pollutant, and Rotterdam Convention substance. We queried the entire database and ranked every substance by the number of simultaneous classifications it carries. The result: out of 47,000+ substances, only three carry 5 flags. No substance carries more than 5. The three most classified substances 1. Formaldehyde — CAS 50-00-0 Flag Details Toxic Acute toxicity 1%, chronic toxicity 0.1% Restricted Banned in furniture veneer, textiles, children's products (age 3 and under), wallpaper paste, leather softeners at 1%+ Priority management Flagged as CMR Accident preparedness Emergency plans required for facilities handling 1%+ mixtures Registration required Must be registered before comm...

Most people do not think about chemical regulations until something goes wrong. A product recall, a news headline about contaminated toys, a warning label on a can of paint. But chemical regulations are not just about factory accidents and industrial waste. Some of the most heavily regulated substances in Korea are found in products that people encounter every day — furniture, paint, batteries, jewelry, and cleaning products. Korea manages chemical substances through K-REACH (Act on Registration, Evaluation, etc. of Chemical Substances), one of the most detailed chemical regulation frameworks in Asia. Unlike systems that classify a substance as simply "banned" or "allowed," K-REACH assigns substances to multiple regulatory categories simultaneously. A single chemical can be classified as toxic, restricted, subject to accident preparedness requirements, and flagged as a CMR substance. We looked up five chemicals that are present in everyday products and checked th...