Outdoor & Yard / Compounds / Sulfur mustard (mustard gas)

Sulfur mustard (mustard gas) in the yard and garden

High risk for your yard

Not medical, veterinary, or professional safety advice, and not a substitute for a qualified professional — consult one. Full disclaimer →

IARC Group 1; both a potent vesicant (blister agent) and long-term carcinogen. A Chemical Weapons Convention Schedule 1 substance — production, stockpiling, and use as a weapon is prohibited globally. This entry covers: (1) historical occupational exposure in WWI/WWII production workers who developed lung and respiratory tract cancers 20–40 years later; (2) residual contamination at former US production sites (Edgewood Arsenal MD, Rocky Mountain Arsenal CO, Aberdeen Proving Ground MD); (3) civilian populations near former weapons test sites or sea-dumped munitions. Mechanism: forms highly reactive sulfonium ions → alkylates DNA and proteins; cross-links DNA strands, associated with mutagenic lesions; also depletes glutathione, with oxidative stress.

What is sulfur mustard (mustard gas)?

The IUPAC name is 1-chloro-2-(2-chloroethylsulfanyl)ethane.

Also known as: 1-chloro-2-(2-chloroethylsulfanyl)ethane, Mustard gas, Sulfur mustard, Yperite.

IUPAC name
1-chloro-2-(2-chloroethylsulfanyl)ethane
CAS number
505-60-2
Molecular formula
C4H8Cl2S
Molecular weight
159.08 g/mol
SMILES
C(CCl)SCCCl
PubChem CID
10461

Risk for people, pets,

High risk

IARC Group 1; both a potent vesicant (blister agent) and long-term carcinogen. A Chemical Weapons Convention Schedule 1 substance — production, stockpiling, and use as a weapon is prohibited globally. This entry covers: (1) historical occupational exposure in WWI/WWII production workers who developed lung and respiratory tract cancers 20–40 years later; (2) residual contamination at former US production sites (Edgewood Arsenal MD, Rocky Mountain Arsenal CO, Aberdeen Proving Ground MD); (3) civilian populations near former weapons test sites or sea-dumped munitions. Mechanism: forms highly reactive sulfonium ions → alkylates DNA and proteins; cross-links DNA strands, associated with mutagenic lesions; also depletes glutathione, with oxidative stress.

Regulatory consensus

5 regulatory and scientific bodies have classified Sulfur mustard (mustard gas). The classifications differ — that's the data.

AgencyYearClassificationNotes
IARC1987Group 1 (carcinogenic to humans)IARC Supplement 7 (1987), originally Monograph 9 (1975). Sufficient evidence in humans (lung cancer, pharyngeal/laryngeal cancer, esophageal cancer in WWI and WWII veterans with mustard gas exposure) and animals. A bifunctional alkylating agent forming DNA intrastrand and interstrand cross-links; also a potent vesicant causing severe tissue injury independent of carcinogenicity.
EPA CTX / NTP RoCKnown Human Carcinogen
EPA CTX / IARCGroup 1 - Carcinogenic to humans
EPA CTX / CalEPAListed by California as known to the State to cause cancer (Proposition 65)
EPA Genetox (via EPA CTX / Genetox)Genotoxicity: positive (Ames: positive, 10 positive / 0 negative reports)
Japan (via EPA CTX / Skin-Eye)Eye Irritation: Category 1 (score: very high)
Japan (via EPA CTX / Skin-Eye)Skin Irritation: Category 1 (score: very high)

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where your yard encounter sulfur mustard (mustard gas)

  • Outdoor AirVehicle exhaust, Industrial emissions, Power plant discharge
  • Indoor AirCombustion byproducts, Office buildings, Parking garages

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Sulfur mustard (mustard gas):

  • Safer process chemistry; Green chemistry alternatives; Exposure controls
    Trade-offs: Requires R&D investment to redesign synthesis routes; may reduce yield or throughput initially; long-term benefits include reduced waste treatment costs, regulatory compliance, and worker safety; 12 Principles of Green Chemistry framework available.
    Relative cost: 2-5×

Frequently asked questions

Is sulfur mustard (mustard gas) safe for your yard?

IARC Group 1; both a potent vesicant (blister agent) and long-term carcinogen. A Chemical Weapons Convention Schedule 1 substance — production, stockpiling, and use as a weapon is prohibited globally. This entry covers: (1) historical occupational exposure in WWI/WWII production workers who developed lung and respiratory tract cancers 20–40 years later; (2) residual contamination at former US production sites (Edgewood Arsenal MD, Rocky Mountain Arsenal CO, Aberdeen Proving Ground MD); (3) civilian populations near former weapons test sites or sea-dumped munitions. Mechanism: forms highly reactive sulfonium ions → alkylates DNA and proteins; cross-links DNA strands, associated with mutagenic lesions; also depletes glutathione, with oxidative stress.

What products contain sulfur mustard (mustard gas)?

Sulfur mustard (mustard gas) appears in: Vehicle exhaust (Outdoor air); Industrial emissions (Outdoor air); Combustion byproducts (Indoor air); Office buildings (Indoor air).

Why do regulators disagree about sulfur mustard (mustard gas)?

Sulfur mustard (mustard gas) has been classified by 5 agencies including IARC, EPA CTX / NTP RoC, EPA CTX / IARC, EPA CTX / CalEPA, EPA CTX / Genetox, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See Sulfur mustard (mustard gas) in the outdoor app

Look up products containing sulfur mustard (mustard gas), compare to alternatives, and explore the full data record.

Open in outdoor View raw API data

Sources (3)

  1. IARC Monographs Volume 100F: Sulfur Mustard — Chemical Agents and Related Occupations (2012 evaluation; supersedes Vol 9 / Supplement 7, 1987) (2012) — regulatory
  2. US EPA: Chemical Warfare Agents (blister agents incl. Sulfur Mustard) — emergency response hub — regulatory
  3. ATSDR Medical Management Guidelines for Blister Agents: Sulfur Mustard Agent H/HD, Sulfur Mustard Agent HT (2011) — report

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →