CAS 7783-06-4 · TSCA · United States of America

Hydrogen sulfide (H2S) under TSCA

H2S · 硫化氢

Status: Listed. Hydrogen sulfide is on the TSCA Inventory and currently listed as TSCA Active. **OSHA PEL for hydrogen sulfide at 29 CFR 1910.1000 Table Z-2: 20 ppm ceiling + 50 ppm peak 10-minute (verify against https://www.osha.gov/annotated-pels before relying); the 1989 OSHA Air Contaminants Final Rule that proposed a 10 ppm 8-hr TWA was vacated; current legacy ceiling-and-peak structure applies. NIOSH REL: 10 ppm 10-minute ceiling (verify against cdc.gov/niosh).** **EPA RMP threshold quantity 10,000 lb at 40 CFR Part 68 (verify against https://www.ecfr.gov/ before relying); H2S is on the EPA RMP Section 112(r) regulated substances list**. NOT on DEA scheduling. NOT on California Proposition 65 specifically for hydrogen sulfide (verify against OEHHA https://oehha.ca.gov/proposition-65/proposition-65-list before relying on negative listing). NO direct US AD/CVD on hydrogen sulfide (not a tradable customs commodity at scale). **EPA Clean Air Act Section 112 hazardous air pollutant (HAP) listing applies for H2S** (verify current Section 112 HAP list against https://www.epa.gov/haps before relying). Major US H2S captive sources at refinery / petrochemical / sour-gas plants: ExxonMobil + Phillips 66 + Marathon Petroleum + Valero + Chevron US refinery operations + Permian + Eagle Ford sour-gas captive; verify each producer-site pair against the producer's public website before relying.

US hydrogen sulfide lane: **OSHA PEL 20 ppm ceiling + 50 ppm peak 10-min Table Z-2 + NIOSH REL 10 ppm 10-min ceiling + EPA RMP 10,000 lb + EPA Clean Air Act Section 112 HAP**. NOT on Cal Prop 65 specifically. NO direct US AD/CVD. H2S is captive intermediate at refinery / petrochemical / sour-gas plants. Major US sources: ExxonMobil + Phillips 66 + Marathon Petroleum + Valero + Chevron US refinery operations + Permian + Eagle Ford sour-gas captive.

Listing and threshold

Substance Hydrogen sulfide (H2S) (CAS 7783-06-4), H2S
Regime US Toxic Substances Control Act (TSCA), administered by EPA
Jurisdiction United States of America
Status Listed
Tonnage threshold CDR threshold: 25,000 lb manufactured or imported per site per year

Classifications under this regime

  • OSHA HCS: Acute Tox. 2 inhalation + Flam. Gas 1A + Press. Gas + Aquatic Acute 1
  • OSHA PEL: 20 ppm ceiling + 50 ppm peak 10-minute at 29 CFR 1910.1000 Table Z-2 (verify against https://www.osha.gov/annotated-pels)
  • NIOSH REL: 10 ppm 10-minute ceiling (verify against cdc.gov/niosh)
  • **EPA RMP threshold quantity 10,000 lb at 40 CFR Part 68** (verify against https://www.ecfr.gov/)
  • **EPA Clean Air Act Section 112 hazardous air pollutant (HAP)** (verify current HAP list against https://www.epa.gov/haps)
  • NOT on DEA List I or List II
  • NOT on California Proposition 65 list specifically for hydrogen sulfide (verify against OEHHA before relying on negative listing)
  • DOT 49 CFR 172.101: UN 1053 Class 2.3 + 2.1
  • IARC: Not classified

Restrictions and conditions of use

  • NO direct US AD/CVD on hydrogen sulfide (not a tradable customs commodity at scale)
  • OSHA PEL 20 ppm ceiling + 50 ppm peak 10-minute Table Z-2
  • **EPA RMP threshold quantity 10,000 lb** triggers Risk Management Plan with offsite consequence analysis
  • **EPA Clean Air Act Section 112 hazardous air pollutant (HAP) listing**
  • EPCRA Tier II / TRI reporting where applicable

Importer obligations

TSCA self-certification regime. **H2S is captive intermediate at refinery / petrochemical / sour-gas plants; merchant cargo is rare**. Major US captive sources: ExxonMobil + Phillips 66 + Marathon Petroleum + Valero + Chevron US refinery operations + Permian + Eagle Ford sour-gas captive.

Required documents

  • TSCA Section 13 Import Certification on customs entry (where applicable)
  • OSHA SDS (Acute Tox. 2 inhalation + Flam. Gas 1A + Aquatic Acute 1 hazard profile)
  • CBP Form 7501 with HS 281110
  • CDR filing every 4 years
  • DOT documentation for UN 1053 Class 2.3 + 2.1
  • EPA RMP filing where applicable
  • EPCRA Tier II / TRI reporting where applicable

Common compliance traps

The pitfalls that have bitten importers on this lane in the past. None of these is theoretical.

  • OSHA PEL: 20 ppm ceiling + 50 ppm peak 10-minute Table Z-2 (1989 final rule 10 ppm TWA was vacated)
  • NIOSH REL substantially more protective: 10 ppm 10-minute ceiling
  • **EPA RMP threshold 10,000 lb** triggers Risk Management Plan
  • **EPA Clean Air Act Section 112 HAP**
  • NO direct US AD/CVD on H2S
  • Major US captive sources: ExxonMobil + Phillips 66 + Marathon Petroleum + Valero + Chevron US refinery operations + Permian + Eagle Ford sour-gas captive

Where to read next

For substance-level identifiers (formula, molecular weight, SMILES, InChIKey), GHS hazard profile, IMDG transport class, and full sourcing reference for hydrogen sulfide (h2s), see the CAS 7783-06-4 sourcing reference.

For grade-by-grade buying notes, freight maths, supplier-tier pricing, and a worked landed-cost example, the hydrogen sulfide (h2s) cornerstone hub covers the full sourcing chain.

For the structure and history of TSCA, see the TSCA glossary entry.

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Cross-jurisdiction profile and sourcing references

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