Three things a buyer wants to look up before importing an electronic specialty gas into Korea — the HS code, the duty rate, the agency's processing time — we could not establish from any Korean primary source, and no guess appears below. What is fixed is smaller and stranger than most guides suggest: a handful of statutory deadlines, two legal categories constantly treated as one, and a filing route with no quantity threshold at all, so one cylinder of nitrogen trifluoride or silane creates the same filing obligation as a bulk installation. One caveat governs everything here: the Enforcement Rule we worked from is the edition in force from 1 January 2024, and it has been amended at least three times since — most recently effective 11 June 2026 — none of which we could obtain.
Disclaimer: This article is general practical information, not legal, customs or chemical-regulatory advice, and guarantees no classification, duty rate or filing determination for any specific transaction. Verify classification with a licensed customs broker, gas-safety obligations with the competent local authority and the Korea Gas Safety Corporation, and chemical obligations with the regional environment office. Statutes and subordinate rules change.
Four Filings, Three Authorities, and No Public Tariff Line
Paper goes to three places: the city, county or district head (시장·군수·구청장) for import-business registration, import filing and use filing; the Korea Gas Safety Corporation (한국가스안전공사) for the inspection applications and for lodging the import filing; and the environment-ministry chain for the chemical-law side.
Two corrections first. The supervising ministry was renamed: since 1 October 2025 this Act sits with the 산업통상부, formerly 산업통상자원부, and the current statute — Act No. 21438, effective 10 March 2026 — reads "산업통상부장관." The reorganisation moved energy functions to a new climate, energy and environment ministry (기후에너지환경부), but gas safety stayed put. And the fire-service dangerous-substances statute (위험물안전관리법) does not reach compressed gas: the six classes in its decree's Annex 1 are every one a solid or a liquid.
The tariff question has no public answer we can print. Korea Customs published a semiconductor HS interpretation guideline on 24 April 2023 with Samsung Electronics, SK hynix and the Korea Semiconductor Industry Association — almost certainly the document that answers this — but it is a JavaScript flipbook of page images we could not read. We obtained no ten-digit HSK line, no confirmed six-digit heading, no duty rate. Fix the line by advance classification ruling (품목분류 사전심사), as our sputtering target guide sets out for a commodity with the same problem.
「특정고압가스」 and 「특수고압가스」 Are Different Categories
These two terms differ by one character and are routinely conflated, including in guidance for buyers. 특수고압가스 (Enforcement Rule Art. 2(1)(28)) means compressed monosilane, compressed diborane, liquefied arsine, phosphine, hydrogen selenide, germane and disilane, plus other gases the Minister recognises for special purposes such as semiconductor cleaning. It is a definition only, unchanged in substance for two decades. 특정고압가스 comes from Article 20(1) of the Act — hydrogen, oxygen, liquefied ammonia, acetylene, liquefied chlorine, natural gas, compressed monosilane, compressed diborane, liquefied arsine, and further gases set by Presidential Decree — and this is the category that triggers the use filing.
The lists overlap enough that "it is a 특수고압가스, so we file" reaches the right answer often enough to survive as a habit. It is still the wrong reasoning, and it costs money in one place: the exemption from foreign cylinder-manufacturer registration runs off 특수, not 특정.
The Filing Route With No Quantity Threshold
Enforcement Rule Article 46(1) sets out who files. Five routes, only two about volume: having liquefied-gas storage equipment with a capacity of 500 kg or more, or 50 m³ or more of compressed gas, and using specified high-pressure gas; receiving it by pipeline, natural gas excepted; receiving it as automotive fuel; and item 4 — using any of sixteen named gases, no quantity stated.
Item 4 has no threshold (2024 edition): one cylinder is enough. The sixteen are compressed monosilane (SiH₄), compressed diborane (B₂H₆), liquefied arsine (AsH₃), phosphine (PH₃), hydrogen selenide (H₂Se), germane (GeH₄), disilane (Si₂H₆), arsenic pentafluoride (AsF₅), phosphorus pentafluoride (PF₅), phosphorus trifluoride (PF₃), nitrogen trifluoride (NF₃), boron trifluoride (BF₃), sulphur tetrafluoride (SF₄), silicon tetrafluoride (SiF₄), liquefied chlorine (Cl₂) and liquefied ammonia (NH₃), with carve-outs for gas used for testing — where the gas itself is what is tested — and for ammonia used to ferment straw for animal feed in areas the local authority designates.
NF₃ is on the list, so the highest-volume chamber-clean gas in a fab is a trigger irrespective of quantity. Several gases handled just as routinely are not: WF₆, BCl₃, HCl, C₄F₆, C₄F₈, helium, xenon and N₂O reach the filing only through the volume or pipeline routes, and only if they are 특정고압가스 to begin with — which the Presidential Decree may or may not say; we did not confirm. Note too that item 4 names boron trifluoride (BF₃), not boron trichloride (BCl₃).
The filing goes on Form 33, no later than seven days before use begins (Art. 46(2)). Then inspection starts, and the clock is not where people expect. Act Article 20(4) requires a completion inspection before use and periodic inspections after, and Rule Article 48(2) sets the window at 15 days either side of the anniversary of the completion-inspection certificate's issue date — not of commissioning. A late completion inspection drags every later year's window with it.
The safety-manager threshold is a different number, and for compressed gas the two cross. Under Enforcement Decree Annex 3 (as amended 14 May 2019), a use-filing facility above 250 kg liquefied or 100 m³ compressed appoints a general safety supervisor and at least one qualified safety manager; at or below, a general supervisor alone. Against 500 kg / 50 m³ the bands do not line up. For compressed gas, from 50 m³ up to and including 100 m³ you file but need no safety manager. For liquefied item-4 gases the 500 kg figure never engages at all: the filing is quantity-independent, so a safety manager is due from the first kilogram over 250 — well before the volume route would have noticed you. A third threshold can sit below both: under Rule Article 2(2) a site becomes a storage facility (저장소), moving into the permit track under Act Article 4, at 5 tonnes liquefied or 500 m³ compressed — but at 1 tonne and 100 m³ if toxic, and 100 kg or 10 m³ at a permissible concentration of 200 ppm or below.
Who Files What: the Trader's Three Duties Are Not the Buyer's Three
That sales permit reaches gas in containers over 1 litre, expressly including imported gas (Enforcement Decree Art. 3(3), Presidential Decree No. 36400, effective 9 June 2026). The registration reaches toxic gases and gases in Annex 26 — toxic gas being its own definition in Rule Article 2(1)(2), a permissible concentration of 5,000 ppm or below, whose named list includes chlorine, hydrogen chloride, hydrogen fluoride, arsine, monosilane, disilane, diborane, hydrogen selenide, phosphine and monogermane. Seven of the fifteen gases tracked in the air-freight table below are on that named list; WF₆, BCl₃, C₄F₆ and NF₃ may enter by the 5,000 ppm criterion, which we did not check gas by gas.
Two traps. The import filing follows the gas, not the business — an end user importing directly still files it, escaping only the registration — and its exemption for containers under 300 mL expressly excludes toxic gases. And Rule Article 8(1)(5) applies the Annex 9 facility and technical standards to importers as well as sellers, so the registration is no paper qualification.
Getting it wrong is not a fee. Act Article 39 — up to two years' imprisonment or a fine of up to KRW 20 million — covers operating a high-pressure gas import business without the registration required by Article 5의3(1). We read the penalties through an official summary rather than the statute and could not obtain Article 43 (administrative fines), so which provision catches a failure to file the use notification, or use of an overdue cylinder, we could not determine.
Cylinders: Registration, Two Exemptions, and the Return Leg
Korea does run a registration regime for foreign cylinder makers: Act Article 5의2 requires a manufacturer producing containers abroad for export into Korea to register, Article 9의3 provides for cancelling it, and Rule Article 9의2(2) fixes validity at three years, a figure identical in the 2006 edition. We could not confirm the renewal procedure, so do not treat "re-register every three years" as established. Two exemptions run the other way.
- Rule Art. 9의2(1)(6) exempts cylinders charged with 특수고압가스 that are not manufactured in Korea — monosilane, diborane, arsine, phosphine, hydrogen selenide, germane, disilane.
- Rule Art. 9의2(1)(5) covers the return leg: containers imported to carry high-pressure gas and sent back once the gas is spent are exempt — provided they were inspected by a foreign body recognised by the Minister, against the Annex 10, 10의2 and 12 criteria.
That condition is a supplier-selection question, and belongs in qualification, not at the border. Here the gas-safety statute answers the registration side of the return leg directly; the customs side, next, is as open as it was for targets.
The customs side we could not settle. Article 99 (re-import exemption) points the wrong way — it covers containers of exported goods coming home — and against the live provisions, Customs Act Articles 97 and 98, we found no source on cylinder ownership structure. Nor is any demurrage or rental schedule published. Put in the contract instead: return deadline, return freight, replacement value of a cylinder not returned, cylinders falling due for re-inspection in Korea, and who pays for valve replacement.
The Cylinder Is Re-Inspected; the Valve Is Scrapped
Re-inspection intervals sit in Annex 22 (as amended 21 May 2019), under Act Article 17(2)(1). Cross-checked against an independent reproduction; later amendments not verified.
The two blank columns are not missing data: Annex 22 does not split seamless or composite containers into the 15- and 20-year age tiers at all — their entire aging rule is the one given in the first column. Intervals run from the new-inspection date, or the last re-inspection. Fab-size cylinders are usually seamless, under 500 L — industry practice, not statute; confirm against the cylinder.
Note 5: for containers under 125 L internal volume, the fittings — valves — are scrapped, not re-inspected, at the first container re-inspection that falls more than two years after the fitting's own manufacture or import inspection. Standard 44 L and 47 L cylinders sit inside that band. Note 6: composite containers are scrapped 15 years from the manufacturing inspection, with no extension. Gas cylinder cabinets (고압가스용 실린더캐비닛) are excluded from re-inspection altogether — distinct from the facility's own periodic inspection.
Ten of the Fifteen Gases Cannot Be Flown
A source caveat that matters: the last column comes from the US 49 CFR §172.101 Hazardous Materials Table, not IATA's Dangerous Goods Regulations, whose Table 4.2 is a paid publication we did not obtain; summaries attributing this data to IATA are wrong at the source. The permitted gases carry limits of 75 kg on passenger and 150 kg on cargo aircraft, and C₄F₆ has no dedicated UN number — suppliers declare it under the general n.o.s. entry 3160.
Ten of fifteen are forbidden on both passenger and cargo aircraft. There is no air-freight rescue. The move that works for a powder when a shipment slips — fly the next lot — does not exist for two thirds of this list, leaving only inventory depth and a qualified second source, both decided long before the shortage. And the reversal in the table is the part to internalise: NF₃, the largest-volume gas here, flies; the small-volume dopants — arsine, phosphine, diborane, germane — do not. Size inventory by consumption and you under-protect exactly the gases with no recovery path.
Sea freight does not close the gap: class 2.3 cargo needs carrier dangerous-goods booking approval and a designated stowage position, for which no duration is public. And at the port, sequence matters — Incheon's container procedures require hazardous-chemical dangerous goods to be removed from the terminal within 72 hours of discharge or gate-in, on pain of fines and suspension of dangerous-goods handling. Bring a gas that is a 유해화학물질 — a designation we could not confirm gas by gas — in before the use filing and completion inspection are done, and a 72-hour clock starts on the quay. That rests on a single Incheon source; whether Busan matches it we did not confirm.
The Deadlines the Statute Fixes, and the Ones Nobody Publishes
There is no honest "N weeks from PO to gas at the tool" figure. What the statute fixes:
Everything else is privately held: filling lead times, carrier approval times, port dwell times, clearance statistics. Statutory processing times are no better: Government24 (정부24), the government's civil-affairs portal, returned three different values on three retrievals for the same filing, so we print none. Ask the office handling your filing.
Korea Deleted 「유독물질」; 「독성가스」 Is a Different, Live Concept
Much Korean import guidance online still uses a term the statute deleted. Under the Chemical Substances Control Act (화학물질관리법) as amended by Act No. 20231 of 6 February 2024 and effective 7 August 2025, Article 2(8) — the definition of 「유독물질」 — reads "deleted." The category no longer exists; what it covered was redistributed by hazard type into 인체급성유해성물질 (acutely human-hazardous), 인체만성유해성물질 (chronically human-hazardous) and 생태유해성물질 (ecologically hazardous), and 유해화학물질 in Article 2(7) now means those three plus 사고대비물질 (accident-preparedness substances). Article 20, formerly the import filing for 유독물질, is now 「인체급성유해성물질 등의 수입신고」. A template still saying 유독물질 predates August 2025.
This does not touch 「독성가스」. Toxic gas is a separate concept in a separate statute — Enforcement Rule Article 2(1)(2) of the High-Pressure Gas Safety Control Act, permissible concentration of 5,000 ppm or below — and very much live, because it is what pulls an importer into the import-business registration above. Different statute, different list, different ministry, and the easiest thing to get wrong here.
Two duties also bite before shipment, not at the border: K-REACH, where registration and annual reporting are separate obligations, as our SiC powder import guide sets out; and the safety data sheet, a pre-import filing under Occupational Safety and Health Act Article 110 that Article 113 lets a foreign maker discharge through an appointee in Korea — the route when it will not disclose composition. One last assumption is worth killing: NF₃ was not among the six gases Korea's carbon-neutrality framework act defines as greenhouse gases as of August 2024, per a paper in the Journal of Climate Change Research Vol. 15 No. 4 — read through its abstract, not the body — so do not expect a greenhouse-gas inventory duty from it; its emissions are policed on other grounds.
What We Could Not Establish
- Unobtainable. HS classification and duty rates; the processing time for any filing; the contents of Annexes 8, 9 and 26; the text of Act Article 43; which foreign inspection bodies the Minister recognises. Also every strategic-goods control number: the dual-use annex downloads returned server errors, so none appears here. Arsine, phosphine and diborane are plausible Australia Group items, but plausible is not a determination; self-classification (자가판정) is how you replace it with one, alongside a 수입목적확인서 confirming declared end use for the supplier's licence application, as our sputtering target guide describes. Equally unresolved: whether any gas here is a scheduled chemical under the chemical-weapons prohibition act, where Schedule 1 imports need a permit and notification 40 days before delivery; which gases are designated human- or ecologically hazardous; and whether a pure importer needs a chemical business permit.
- Looked for and not found: any Korean anti-dumping measure on a specialty gas — searched, not surveyed, so ask for a case number if told otherwise; any basis for US or Japanese equipment controls listing these gases themselves; and germanium tetrafluoride or germane on China's 2023 germanium list, whose items run to germanium metal, zone-refined ingot, zinc germanium phosphide, epitaxial substrate, germanium dioxide and germanium tetrachloride. We read that announcement through law-firm analyses, and absence is weaker evidence than presence. The chronology is in our export-controls timeline, and whether the 2023 licensing requirement was ever lifted in our three-year review.
Before the First Order
- Fix the tariff line by 품목분류 사전심사 on the cylinder-and-gas you will actually import.
- Check every gas against item 4 of Rule Art. 46(1); if named, file Form 33 seven days before use, whatever the volume.
- Read the safety-manager threshold (250 kg / 100 m³, Annex 3) separately from the filing threshold.
- Ask the supplier which foreign inspection body certified its cylinders — the Rule Art. 9의2(1)(5) exemption turns on it.
- Put return deadline, freight, replacement value, re-inspection fall-due and valve scrappage in the supply agreement.
- Do not land gas before the use filing and completion inspection are done.
Frequently Asked Questions
Which specialty gases require a 특정고압가스 use filing in Korea, and at what volume?
Two routes. At a storage capacity of 500 kg or more of liquefied or 50 m³ or more of compressed gas the filing follows the volume. But item 4 of Enforcement Rule Article 46(1) names sixteen gases — monosilane, diborane, arsine, phosphine, hydrogen selenide, germane, disilane, AsF₅, PF₅, PF₃, NF₃, BF₃, SF₄, SiF₄, chlorine and ammonia — with no quantity threshold, so one cylinder triggers it, subject to carve-outs for testing the gas itself and for a straw-fermentation feed use of ammonia. WF₆, BCl₃, HCl, C₄F₆, C₄F₈, helium, xenon and N₂O are not on that list.
What HS code and duty rate apply to a specialty gas import into Korea?
We could not establish either from a Korean primary source — Korea Customs published a semiconductor HS interpretation guideline in April 2023, but in a format we could not read. Fix the line by advance classification ruling on the article you will actually import, and treat any gas-by-gas HS table you are handed as unverified.
Can we air-freight specialty gas into Korea if a shipment fails?
For most of this list, no. On the US hazardous materials table, ten of the fifteen gases here — silane, arsine, phosphine, diborane, germane, WF₆, anhydrous HCl, chlorine, BCl₃ and C₄F₆ — are forbidden on both passenger and cargo aircraft; NF₃, C₄F₈, helium, xenon and N₂O are permitted at 75 kg passenger and 150 kg cargo. We did not cross-check IATA's own table, a paid publication. Inventory and a second source are the only levers left, and the exposure is worst on the low-volume dopants.
References (Public Sources)
- Held in full: the Enforcement Rule of the High-Pressure Gas Safety Control Act, edition in force from 1 January 2024, Articles 2, 8, 9의2, 10의2, 27, 39, 46, 48 and 49, with Annex 22 (as amended 21 May 2019) cross-checked against an independent reproduction, plus Enforcement Decree Annex 3 and Article 3(3); KGS Code FU211 (use-facility standard) and AC212 (seamless-cylinder manufacture) by title only, texts not obtained. Read directly but partially: Act No. 21438 Articles 15 and 20; Customs Act Articles 97 to 99; Chemical Substances Control Act Article 2 as amended by Act No. 20231, with Articles 20, 27 and 28; 위험물안전관리법 시행령 별표 1; the US 49 CFR §172.101 table, with safety data sheets from non-Chinese gas producers.
- Secondary or unobtained: Act Articles 5의2, 5의3 and 21, and the penalties, through an official summary page, Article 43 not obtained; the Enforcement Rule editions after 1 January 2024 (latest effective 11 June 2026), and Annexes 8, 9 and 26; the re-export exemption notice; IATA Table 4.2; the dual-use annex; Occupational Safety and Health Act Articles 110 and 113; Incheon port procedures; Foreign Trade Act Article 19; China's 2023 gallium and germanium announcement and the US and Japanese equipment measures, via law-firm analyses.
Article numbers above reflect an Enforcement Rule edition that has since been amended; filings, thresholds and inspection practice all move.
Nami Tech Solutions (NTS) does not hold specialty gas as a standing line, and nothing above is an offer of supply. What we do is the project work around it: establishing which filings a given structure triggers before the first purchase order, putting cylinder inspection status and return terms into the supply agreement rather than discovering them at the quay, and taking the classification and control questions to the authorities that answer them in writing.
