HazMat Tool — substance information

Sulfur dioxide

HMT 15 June 2026
Reference only — HMT snapshot for inspection and audit support; not a shipping paper, placard mandate, or CVI record. Use Print / PDF below for field notes.
UN / ID
UN 1079
Hazard class
2.3
Packing group
ERG guide
ERG 125
Special provisions
SP 3, SP B14, SP T50, SP TP19
Source
49 CFR §172 (15 June 2026)

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Sulfur dioxide


Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula SO2. It is a colorless gas with a pungent smell that is responsible for the odor of burnt matches. It is released naturally by volcanic activity and is produced as a by-product of metals refining and the burning of sulfur-bearing hydrocarbon fuels. Sulfur dioxide is somewhat toxic to humans, although only when inhaled in relatively large quantities for a period of several minutes or more. It was known to medieval alchemists as "volatile spirit of sulfur" Wikipedia

Substance Data

Source: PubChem (HSDB, 04.12.2019)

CAS-Number

7446-09-5

Flash Point

n/a

Boiling Point

n/a

Emergency Response Guide No. 125

Hazardous Materials Table

Source: 49 CFR §172 (15 June 2026)

(3) Hazard Class

2.3
Poisonous gas

(4) Identification number Help

UN 1079

(5) Packing Group Help

n/a

(6) Labels Help

Poisonous gas (2.3) Corrosive liquids (8)

(7) Special Provisions (§172.102) Help

×Note:
Special provisions may be very complex. The extracts are taken from 49 CFR §172.102. Please be careful with the information, as necessary, additional conditions may be applied that are not written here. Please check the original source and report bugs.
3
B14
T50
TP19

(8) Packing Authorizations (§173.***) Help

(8A) ExceptionsNone
(8B) Non-bulk304see 49 CFR §173.304
(8C) Bulk314, 315see 49 CFR §173.314, 315

(9) Quantity Limits Help

(9A) Passenger aircraft/railForbidden
(9B) Cargo aircraft onlyForbidden

(10) Vessel stowage Help

(10A) Location
(10B) Other

Segregation chart for load, transport, and storage

This chart shows whether loading, transport, or storage with other hazard classes is permitted, prohibited, or restricted. Based on 49 CFR §177.848.

Scope & sources (important)Click to show CFR references

This check evaluates segregation per 49 CFR §177.848. Additional loading/unloading and handling requirements may still apply; see 49 CFR §177 Subpart B (Loading and Unloading):

  • §177.834 - General requirements
  • §177.835 - Class 1 materials
  • §177.837 - Class 3 materials
  • §177.838 - Class 4 (flammable solid) materials, Class 5 (oxidizing) materials, and Division 4.2 (pyroforic liquid) materials
  • §177.839 - Class 8 (corrosive) materials
  • §177.840 - Class 2 (gases) materials
  • §177.841 - Division 6.1 and Division 2.3 materials
  • §177.842 - Class 7 (radioactive) material
  • §177.843 - Contamination of vehicles