HazMat Tool — substance information

Phosphine, adsorbed

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 3525
Hazard class
2.3
Packing group
ERG guide
ERG 173
Special provisions
SP 1
Source
49 CFR §172 (15 June 2026)

Spot an error in this entry?

Phosphine, adsorbed


Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula PH3, classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting fish, due to the presence of substituted phosphine and diphosphane (P2H4). With traces of P2H4 present, PH3 is spontaneously flammable in air (pyrophoric), burning with a luminous flame. Phosphine is a highly toxic respiratory poison, and is immediately dangerous to life or health at 50 ppm Wikipedia

Emergency Response Guide No. 173

Hazardous Materials Table

Source: 49 CFR §172 (15 June 2026)

(3) Hazard Class

2.3
Poisonous gas

(4) Identification number Help

UN 3525

(5) Packing Group Help

n/a

(6) Labels Help

Poisonous gas (2.3) Flammable gases (2.1)

(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.
1

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

(8A) ExceptionsNone
(8B) Non-bulk302csee 49 CFR §173.302c
(8C) BulkNone

(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.

Prohibited Must not be loaded, transported, or stored together in the same vehicle or facility.
Permitted May be loaded, transported, or stored together.
Restricted May be loaded, transported, or stored together only with restrictions.

Similar substances

UN / IDProper shipping nameHazard class
UN 29409-Phosphabicyclononanes or Cyclooctadiene phosphines4.2
UN 2501Tris-(1-aziridinyl)phosphine oxide, solution6.1
UN 2199Phosphine2.3