HazMat Tool — substance information

Chlorine, adsorbed

HMT May 2026
UN / ID
UN 3520
Hazard class
2.3
Packing group
ERG guide
ERG 173
Special provisions
SP 2, SP B9, SP B14, SP N86
Source
49 CFR §172 (2026/05)

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Chlorine, adsorbed


Chlorine is a chemical element; it has symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the revised Pauling scale, behind only oxygen and fluorine. Chlorine played an important role in the experiments conducted by medieval alchemists, which commonly involved the heating of chloride salts like ammonium chloride (sal ammoniac) and sodium chloride (common salt), producing various chemical substances containing chlorine such as hydrogen chloride, mercury(II) chloride (corrosive sublimate), and aqua regia. Wikipedia

Emergency Response Guide No. 173

Hazardous Materials Table

Source: 49 CFR §172 (2026/05)

(3) Hazard Class

2.3
Poisonous gas

(4) Identification number Help

UN 3520

(5) Packing Group Help

n/a

(6) Labels Help

Poisonous gas (2.3) Oxidizers (5.1) 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.
2
B9
B14
N86

(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.