On Thursday 1 October 2026 the Fair Trade Investigation Division of the Seoul Central District Prosecutors’ Office indicted six chemical companies on charges of violating South Korea’s Monopoly Regulation and Fair Trade Act. Prosecutors allege that from 2021 until April 2026 the companies fixed the prices of eight products “supplied domestically,” and the timing of every change. The list reads like the product sheet of a chlor-alkali plant: caustic soda, chlorine, hydrochloric acid and hypochlorite, plus PVC, epichlorohydrin (ECH), toluene diisocyanate (TDI) and plasticizers. Korean outlets describe it as the largest cartel case the country’s prosecutors have brought.
The detail worth keeping is how prosecutors say it was hidden. As reported by Yonhap, “to conceal the collusion, they pre-arranged the order in which each company would send out official price-increase notices.” Buyers were not sent the same letter on the same day. Each supplier’s letter came on its turn. That is aimed squarely at the warning sign most procurement teams are taught to look for, and it is why this case is worth reading even if you have never bought a drum from Korea.
This is a market-structure piece written for buyers. It reports what prosecutors allege, not what a court has found. It forecasts no price and names no individual, and every fact comes from published reporting, a US government guide or a US government supply profile, all listed at the end.
What prosecutors allege, in order
Every date and figure below is from Korean wire and newspaper reports of the prosecutors’ announcements. Where the reports differ, the table says so rather than picking one.
| When | What happened |
|---|---|
| 2021 to April 2026 | The period of the alleged collusion. Aju Business Daily gives January 2021 as the start, the Korea Times and Korea JoongAng Daily give November 2021, and Yonhap says 2021. All agree it ran to April 2026. |
| April to June 2026 | The government provides about 146.5 billion won to support petrochemical production. The Korea Times reports that “the alleged collusion continued despite” that support. |
| 5 August 2026 | Prosecutors carry out simultaneous raids on seven companies: the six later indicted and Hanwha Solutions. |
| 14 September 2026 | Prosecutors request arrest warrants for eight current and former executives. A court later issues two and rejects the rest. |
| 1 October 2026 | Six companies indicted, along with 37 current and former staff according to Yonhap and Aju, or 43 according to the Korea Times and Korea JoongAng Daily. Hanwha Solutions is not charged; Yonhap reports this is “widely attributed to its leniency application.” |
Two things are missing from that table, and both matter. No court has ruled; an indictment is an accusation, not a verdict. And none of the reports we read carried a response from the companies. Read everything below with both in mind.
Why the list reads like one plant
The eight products are not a random group. Seven of them come out of a chlor-alkali cell or are made from its chlorine, and the eighth goes into one of the seven.
| Product on the list | How it connects to the chlor-alkali cell |
|---|---|
| Chlorine | Made directly in the cell, at the anode, from salt brine and electricity. |
| Caustic soda (sodium hydroxide) | Made directly in the same cell, at the cathode: 1.128 tonnes for every tonne of chlorine. |
| Hydrochloric acid | Made from the cell’s chlorine, by burning it in the cell’s hydrogen or as a byproduct of the plants that use chlorine. |
| Hypochlorite | Made by reacting the cell’s chlorine with its own caustic soda. |
| PVC | The largest outlet for chlorine. PVC is 56.7% chlorine by mass. |
| Epichlorohydrin (ECH) | A chlorinated intermediate for epoxy resins. |
| Toluene diisocyanate (TDI) | Made through phosgene, which is made from chlorine. Isocyanate plants are one of the byproduct sources of hydrochloric acid named by the US EPA. |
| Plasticizers | Not chlorinated, but a large share goes into flexible PVC. |
We covered the arithmetic behind that link last week in Chlorine, Caustic Soda and Hydrochloric Acid Come Out of One Cell. The short version: a producer cannot make chlorine without making caustic soda in a fixed ratio, and most hydrochloric acid is what is left after chlorine has been used. The US EPA says “chlor-alkali producers generally set chlor-alkali production around demand for chlorine.” Producers therefore think about the cell’s outputs together, and price them together in the electrochemical unit explained in our caustic soda guide.
That is chemistry, not evidence. Prosecutors have not said why the list covers these eight products, and the structure of a plant proves nothing about anyone’s conduct. It does explain why a single case can reach caustic soda, hydrochloric acid and bleach all at once. A buyer of any one of them is buying from the same small set of cells.
The one-sentence version. Korean prosecutors allege that six companies agreed how much and when to raise prices on a chain of chlorine products, and sent their notices in a pre-agreed order so the increases would not look coordinated.
The test the alleged scheme was built to beat
The US Department of Justice publishes a short primer for buyers, Price Fixing, Bid Rigging, and Market Allocation Schemes: What They Are and What to Look For. It begins with a warning: “Collusive agreements are usually reached in secret, with only the participants having knowledge of the scheme.” It then lists patterns that “seem at odds with a competitive market and suggest the possibility of collusion.” Set beside what Korean prosecutors allege, three of them stand out.
| DOJ warning sign (quoted) | What prosecutors allege in Seoul | Would a buyer have seen it? |
|---|---|---|
| “Identical prices may indicate a price-fixing conspiracy” | The size and timing of each increase were agreed, but the notices were sent in a pre-arranged order. | Not at a glance. Letters arriving on different dates look like followers reacting to a leader. The pattern only shows if you line up the dates. |
| “Price increases do not appear to be supported by increased costs.” | The alleged collusion continued through a year in which the government was supporting petrochemical production. | Hard to see. When costs are genuinely rising, a cost-based reason on a price letter is easy to believe. |
| “The same suppliers submit bids and each company seems to take a turn being the successful bidder.” | Prosecutors say the companies agreed in advance which firm would win large buyers’ tenders. | Only if the buyer keeps its own bid history and looks at who won, round by round. |
Taken together, the three show where these tests are weak. They work best on a buyer that compares letters side by side and keeps records over years. A staggered sequence is designed to pass a quick look at the in-tray. Aju Business Daily describes the same tactic as staggering “price increase letters to blunt suspicion.”
None of this suggests that any staggered price increase is collusion. Prices in commodity chemicals often move one supplier at a time for honest reasons: one producer leads, the others follow when their own costs or order books catch up. The DOJ guide is careful to call these patterns things that “suggest the possibility,” not proof. The practical lesson is narrower: a sequence is only visible to someone who records it.
What reaches a US buyer
Directly, very little. Prosecutors describe the products as supplied domestically in South Korea. The US EPA’s water-sector supply profiles show where US trade in these two chemicals actually runs:
| US trade, per EPA supply profiles | Caustic soda (aqueous) | Hydrochloric acid |
|---|---|---|
| US production, 2019 | 11,627 million kg | 1,212 million kg |
| US imports, 2019 | 792 million kg | 308 million kg |
| US exports, 2019 | 6,373 million kg | 61 million kg |
| Main import source, 2015–2020 | Taiwan | Canada |
| Main export destination, 2015–2020 | Brazil | Canada |
The US exported more than half of the caustic soda it made in 2019, and South Korea was not its main source of imports for either chemical. These are the latest figures the EPA profiles give, and trade moves year to year, but they are enough to say that a case about prices inside Korea does not translate into a US price change. It is not a reason to buy ahead of need.
Indirectly, the case is a useful reminder of how chlor-alkali products are priced everywhere. A small number of cell operators make most of the supply in any region. Their outputs are linked by the chemistry, and price changes are announced by letter, usually with a stated reason and an effective date. That structure is common to every chlor-alkali market. The Seoul case shows how one group of companies is alleged to have used it.
What to keep on file for caustic soda and hydrochloric acid
You do not need to suspect anyone to benefit from good records. The same habits that would expose a staggered sequence also make honest quotes easier to compare. Here is what we would keep for every quote and every price letter:
| Record | Why it matters | For caustic soda and hydrochloric acid specifically |
|---|---|---|
| The date each notice arrived and the date it takes effect | A sequence of increases is only visible across dates. One letter tells you nothing. | Keep notices from every supplier in one dated list, including suppliers you did not buy from. |
| The basis of the price | A price per gallon of 50% liquor, per dry ton and per bag of flake are three different numbers for the same chemical. | Convert to price per kilogram of active chemical: 2.90 kg NaOH in a gallon of 50% solution, 1.67 kg HCl in a gallon of 37% acid, 1.36 kg in a gallon of 31%. |
| The stated reason | Lets you check later whether the cost driver actually moved. | Energy, salt and freight are the usual named drivers. Note which one, so you can look it up later. |
| Freight, separately | Delivered cost can swing more than the product price on small packs, which hides product-price changes. | Hazmat freight on a pail or a drum can be a large share of the total. See our delivered-cost guide. |
| The specification you were quoted | A lower price on a different grade is not a lower price. | For caustic, the sodium chloride line (membrane grade about 0.01%, diaphragm up to 1.10% on one 2026 specification). For hydrochloric acid, ACS reagent versus technical. |
| Bid results, if you tender | Rotation of winners only shows across rounds. | Record who bid, who won and at what price, every time. |
What this means on a specification
None of this changes what grade you need. It changes how carefully you should compare the prices of the grade you need.
| Application | What to specify | What to compare on |
|---|---|---|
| pH adjustment, neutralization, general cleaning | Technical-grade sodium hydroxide 25–50%, or technical-grade hydrochloric acid 31% | Price per kilogram of active chemical, delivered. Trace limits rarely matter here. |
| Chloride-sensitive processes and stainless-steel systems | Sodium hydroxide 50% membrane grade | The sodium chloride value on the certificate for your lot, then price per kilogram of NaOH. |
| Metal pickling, scale and rust removal, concrete etching | Technical-grade hydrochloric acid, 31% or 37% | Kilograms of HCl per dollar; a 37% gallon carries about 23% more HCl than a 31% gallon, not 6%. |
| Laboratory titration and reagent work | ACS reagent grade: sodium hydroxide 50% ACS or ACS flake; hydrochloric acid 37% ACS | The full reagent specification. Our ACS versus technical guide covers which jobs need it. |
A word on what this article does not say. It reports what Korean prosecutors allege about six Korean companies and the Korean market, what a US government guide says about spotting collusion, and what US government profiles say about trade. It makes no claim about ours: where the caustic soda and hydrochloric acid we list were made, or how any of our suppliers price. Nobody writing this has checked the first for this article, and the second is not something a market-structure piece should guess at.
Common questions
What are the Korean chemical companies accused of?
Seoul prosecutors allege that LG Chem, OCI, Lotte Fine Chemical, Aekyung Chemical, PKC and Unid fixed the prices and the timing of price changes for eight products sold in South Korea, including caustic soda, hydrochloric acid, hypochlorite and chlorine, from 2021 to April 2026. They value the products at 16.4 trillion won. The companies were indicted on 1 October 2026; no court has ruled.
Does the Korean price-fixing case affect caustic soda prices in the US?
Not directly. Prosecutors describe the products as supplied domestically in South Korea. US EPA profiles show the US exported 6,373 million kg of aqueous caustic soda in 2019 against 792 million kg imported, with Taiwan the main import source, and Canada the main partner for hydrochloric acid. A Korean domestic case is not a reason to change a US purchase.
Why are caustic soda, chlorine and hydrochloric acid in the same case?
They come from the same chlor-alkali cell. Electrolysis of salt brine makes chlorine and caustic soda together, 1.128 tonnes of caustic per tonne of chlorine, and hydrochloric acid is made from that chlorine. Seven of the eight products in the case are made in the cell or from its chlorine. Prosecutors have not said why these products were chosen; the chemistry explains only why they are linked.
What does staggered price-increase notices mean?
Prosecutors allege the companies agreed the order in which each would send its official price-increase letter. Buyers received the increases on different dates instead of all at once. The US Department of Justice lists identical prices as a warning sign of price fixing, and a staggered sequence makes coordinated increases look like ordinary leader-and-follower pricing unless someone records the dates.
How can a buyer spot price fixing?
The US Department of Justice guide lists patterns such as identical prices, increases not supported by costs, and bidders taking turns winning. None is proof. The practical step is record-keeping: log every supplier’s notices with dates and stated reasons, convert quotes to price per kilogram of active chemical, keep freight separate, and record who wins each tender.
Why was Hanwha Solutions not indicted?
Hanwha Solutions was among the seven companies raided on 5 August 2026 but was not charged on 1 October. Yonhap reports that its exclusion is widely attributed to a leniency application, the process by which a company that reports collusion it took part in can receive reduced penalties. Prosecutors’ reasons were not published in the reports we read.
References & Authoritative Sources
The case facts are from Korean wire and newspaper reports of the prosecutors’ announcements; where they differ, the article gives both. The warning signs are quoted from the US Department of Justice. Trade figures are from US EPA supply-chain profiles. The chemistry uses standard molar masses.
- Prosecutors indict 6 petrochemical firms, 37 executives over W16tr price-fixing scheme — The Herald Business (Yonhap), 1 October 2026. Fair Trade Investigation Division; Monopoly Regulation and Fair Trade Act; the eight products “supplied domestically”; the pre-arranged order of price-increase notices; tenders agreed in advance; Hanwha Solutions and leniency.
- Six petrochemical companies indicted for price-fixing — The Korea Times, 1 October 2026. 16.39 trillion won; November 2021 to April 2026; 43 current and former staff; 146.5 billion won of government support.
- Six petrochemical companies indicted for price-fixing — Korea JoongAng Daily, 1 October 2026. 16.4 trillion won; November 2021 to April.
- Korean chemical makers charged over record cartel — Aju Business Daily, 1 October 2026. January 2021 to April 2026; team-leader meetings; staggered price-increase letters; Hanwha Solutions raided and not charged.
- Arrest warrants sought for 8 petrochemical executives over alleged price fixing — The Korea Times (Yonhap), 14 September 2026. Seven companies under suspicion; simultaneous raids on 5 August.
- Price Fixing, Bid Rigging, and Market Allocation Schemes: What They Are and What to Look For — US Department of Justice, Antitrust Division. The bid and price patterns quoted in this article.
- Sodium Hydroxide Supply Chain Profile (PDF) — US EPA. 2019 production, imports and exports; Taiwan and Brazil as main trade partners 2015–2020; production set around chlorine demand.
- Hydrochloric Acid Supply Chain Profile (PDF) — US EPA. 2019 production, imports and exports; Canada as main partner; isocyanates among byproduct sources.
- Chlorine, Caustic Soda and Hydrochloric Acid Come Out of One Cell — Alliance Chemical, 1 October 2026. The cell arithmetic, the membrane and diaphragm specification, and the per-kilogram table this article reuses.
The caustic soda and hydrochloric acid we stock
Comparing caustic soda or hydrochloric acid quotes?
Send us the application and the quotes you are weighing. We will tell you which grade the job actually needs and show the price per kilogram of active chemical for each strength, so you are comparing like with like.
See every caustic soda grade and strengthKey numbers and sources
| Number | What it is | Source |
|---|---|---|
| 16.4 trillion won | Value of the eight products in the alleged scheme (reported as 16.37–16.39 trillion; $11.8–12.1 billion) | Yonhap, Korea Times, JoongAng, Aju |
| 6 / 7 | Companies indicted / companies raided on 5 August 2026 | Yonhap via Herald and Korea Times |
| 146.5 billion won | Government support for petrochemical production, April to June 2026 | Korea Times; Herald |
| 6,373 / 792 million kg | US exports / imports of aqueous caustic soda, 2019 | US EPA sodium hydroxide profile |
| 1.128 t | Sodium hydroxide made per tonne of chlorine | Stoichiometry (80.00/70.91) |
| 2.90 / 1.67 / 1.36 kg | Active chemical per US gallon: NaOH 50%, HCl 37%, HCl 31% | Product-page densities; arithmetic |
Frequently asked questions
What are the Korean chemical companies accused of?
Seoul prosecutors allege that LG Chem, OCI, Lotte Fine Chemical, Aekyung Chemical, PKC and Unid fixed the prices and the timing of price changes for eight products sold in South Korea, including caustic soda, hydrochloric acid, hypochlorite and chlorine, from 2021 to April 2026. They value the products at 16.4 trillion won. The companies were indicted on 1 October 2026; no court has ruled.
Does the Korean price-fixing case affect caustic soda prices in the US?
Not directly. Prosecutors describe the products as supplied domestically in South Korea. US EPA profiles show the US exported 6,373 million kg of aqueous caustic soda in 2019 against 792 million kg imported, with Taiwan the main import source, and Canada the main partner for hydrochloric acid. A Korean domestic case is not a reason to change a US purchase.
Why are caustic soda, chlorine and hydrochloric acid in the same case?
They come from the same chlor-alkali cell. Electrolysis of salt brine makes chlorine and caustic soda together, 1.128 tonnes of caustic per tonne of chlorine, and hydrochloric acid is made from that chlorine. Seven of the eight products in the case are made in the cell or from its chlorine. Prosecutors have not said why these products were chosen; the chemistry explains only why they are linked.
What does staggered price-increase notices mean?
Prosecutors allege the companies agreed the order in which each would send its official price-increase letter. Buyers received the increases on different dates instead of all at once. The US Department of Justice lists identical prices as a warning sign of price fixing, and a staggered sequence makes coordinated increases look like ordinary leader-and-follower pricing unless someone records the dates.
How can a buyer spot price fixing?
The US Department of Justice guide lists patterns such as identical prices, increases not supported by costs, and bidders taking turns winning. None is proof. The practical step is record-keeping: log every supplier's notices with dates and stated reasons, convert quotes to price per kilogram of active chemical, keep freight separate, and record who wins each tender.
Why was Hanwha Solutions not indicted?
Hanwha Solutions was among the seven companies raided on 5 August 2026 but was not charged on 1 October. Yonhap reports that its exclusion is widely attributed to a leniency application, the process by which a company that reports collusion it took part in can receive reduced penalties. Prosecutors' reasons were not published in the reports we read.
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About the author
Andre Taki
This article is for informational purposes only.