HazMat Tool — substance information

Dichlorosilane

HMT 15 June 2026

UN / ID: UN 2189
Hazard class: 2.3
Packing group: —
ERG guide: ERG 119
Special provisions: SP 2, SP B9, SP B14
Source: 49 CFR §172 (15 June 2026)

On this page

Dichlorosilane

Dichlorosilane, or DCS as it is commonly known, is a chemical compound with the formula H2SiCl2. In its major use, it is mixed with ammonia (NH3) in LPCVD chambers to grow silicon nitride in semiconductor processing. A higher concentration of DCS·NH3 (i.e. 16:1), usually results in lower stress nitride films Wikipedia

Emergency Response Guide No. 119

Hazardous Materials Table

Source: 49 CFR §172 (15 June 2026)

(3) Hazard Class

2.3
Poisonous gas

(4) Identification number

UN 2189

(5) Packing Group

n/a

(6) Labels

(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.

2	This material is poisonous by inhalation (see § 171.8 of this subchapter) in Hazard Zone B (see § 173.116(a) or § 173.133(a) of this subchapter), and must be described as an inhalation hazard under the provisions of this subchapter. Browse special provision 2
B9	Bottom outlets are not authorized. Browse special provision B9
B14	Each bulk packaging, except a tank car or a multi-unit-tank car tank, must be insulated with an insulating material so that the overall thermal conductance at 15.5 °C (60 °F) is no more than 1.5333 kilojoules per hour per square meter per degree Celsius (0.075 Btu per hour per square foot per degree Fahrenheit) temperature differential. Insulating materials must not promote corrosion to steel when wet. Browse special provision B14

(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	304	see 49 CFR §173.304
(8C) Bulk	314, 315	see 49 CFR §173.314, 315

(9) Quantity Limits

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

(10) Vessel stowage

(10A) Location

Stowage category “D” means the material must be stowed “on deck only” 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 the material is prohibited on a passenger vessel in which the limiting number of passengers is exceeded.

Source: 49 CFR §172.101(k)

(10B) Other

17	see 49 CFR §176.84
40	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.

Note: In this segregation and separation chart are HazMat of hazard class 2.3 considered depending on their poisonousness by inhalation (Hazard zone B). See special provision 2 and PHMSA Interpretation #09-0252.

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 2434	Dibenzyldichlorosilane	8
UN 1767	Diethyldichlorosilane	8
UN 1162	Dimethyldichlorosilane	3
UN 1769	Diphenyldichlorosilane	8
UN 1183	Ethyldichlorosilane	4.3
UN 2435	Ethylphenyldichlorosilane	8
UN 1242	Methyldichlorosilane	4.3
UN 2437	Methylphenyldichlorosilane	8
UN 3362	Chlorosilanes, toxic, corrosive, flammable, n.o.s	6.1
UN 2988	Chlorosilanes, water-reactive, flammable, corrosive, n.o.s	4.3
UN 2986	Chlorosilanes, corrosive, flammable, n.o.s	8
UN 2985	Chlorosilanes, flammable, corrosive, n.o.s	3
UN 3361	Chlorosilanes, toxic, corrosive, n.o.s	6.1
UN 2987	Chlorosilanes, corrosive, n.o.s	8
UN 1724	Allyltrichlorosilane, stabilized	8