HazMat Tool — substance information

Calcium hydride

HMT 15 June 2026

UN / ID: UN 1404
Hazard class: 4.3
Packing group: I
ERG guide: ERG 138
Special provisions: SP A19, SP N40, SP W31
Source: 49 CFR §172 (15 June 2026)

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Calcium hydride

Calcium hydride is the chemical compound with the formula CaH2, an alkaline earth hydride. This grey powder (white if pure, which is rare) reacts vigorously with water, liberating hydrogen gas. CaH2 is thus used as a drying agent, i.e. a desiccant Wikipedia

Emergency Response Guide No. 138

Hazardous Materials Table

Source: 49 CFR §172 (15 June 2026)

(3) Hazard Class

4.3
Dangerous when wet materials

(4) Identification number

UN 1404

(5) Packing Group

(6) Labels

Cargo Aircraft Only (Cargo Aircraft Only)

(7) Special Provisions (§172.102)

×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.

A19	Combination packagings consisting of outer fiber drums or plywood drums, with inner plastic packagings, are not authorized for transportation by aircraft. Browse special provision A19
N40	This material is not authorized in the following packagings: a. A combination packaging consisting of a 4G fiberboard box with inner receptacles of glass or earthenware; b. A single packaging of a 4C2 sift-proof, natural wood box; or c. A composite packaging 6PG2 (glass, porcelain or stoneware receptacles within a fiberboard box). Browse special provision N40
W31	Non-bulk packagings must be hermetically sealed. Browse special provision W31

(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	211	see 49 CFR §173.211
(8C) Bulk	242	see 49 CFR §173.242

(9) Quantity Limits

(9A) Passenger aircraft/rail	Forbidden
(9B) Cargo aircraft only	15 kg

(10) Vessel stowage

(10A) Location

Stowage category “E” means the material may be stowed “on deck” or “under deck” on a cargo vessel or on a passenger vessel carrying a number of passengers limited to not more than the larger of 25 passengers, or one passenger per each 3 m of overall vessel length, but is prohibited from carriage on a passenger vessel in which the limiting number of passengers is exceeded.

Source: 49 CFR §172.101(k)

(10B) Other

13	see 49 CFR §176.84
52	see 49 CFR §176.84
148	see 49 CFR §176.84

Source: 49 CFR §176.84

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.

Hazard class	8	7	6.1	5.2	5.1	4.3	4.2	4.1	3	2.3B	2.3A	2.2	2.1	1.6	1.5	1.4	1.3	1.1/1.2
1.1/1.2
1.3
1.4
1.5
1.6
2.1
2.2
2.3A
2.3B
3
4.1
4.2
4.3
5.1
5.2
6.1
7
8

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

Similar substances

UN / ID	Proper shipping name	Hazard class
UN 3487	Calcium hypochlorite, hydrated, corrosive or Calcium hypochlorite, hydrated mixture, corrosive with not less than 5.5% but not more than 16% water	5.1
UN 3485	Calcium hypochlorite, dry, corrosive or Calcium hypochlorite mixture, dry, corrosive with more than 39% available chlorine (8.8% available oxygen)	5.1
UN 2880	Calcium hypochlorite, hydrated or Calcium hypochlorite, hydrated mixture, with not less than 5.5% but not more than 16% water	5.1
UN 3486	Calcium hypochlorite mixture, dry, corrosive with more than 10% but not more than 39% available chlorine	5.1
UN 1748	Calcium hypochlorite, dry or Calcium hypochlorite mixture dry with more than 39% available chlorine (8.8% available oxygen)	5.1
UN 2907	Isosorbide dinitrate mixture with not less than 60 percent lactose, mannose, starch or calcium hydrogen phosphate	4.1
UN 2208	Calcium hypochlorite mixture, dry, with more than 10% but not more than 39% available chlorine	5.1
UN 1403	Calcium cyanamide with more than 0.1 percent of calcium carbide	4.3
UN 1574	Calcium arsenate and calcium arsenite, mixtures, solid	6.1
UN 1855	Calcium, pyrophoric or Calcium alloys, pyrophoric	4.2
UN 2429	Calcium chlorate aqueous solution	5.1
UN 1923	Calcium dithionite or Calcium hydrosulfite	4.2
UN 2844	Calcium manganese silicon	4.3
UN 1314	Calcium resinate, fused	4.1