HazMat Tool — substance information Reference only — not a shipping paper, placard mandate, or CVI record.

Trimethylchlorosilane

HMT 15 June 2026

UN / ID: UN 1298
Hazard class: 3
Packing group: II
ERG guide: ERG 155
Special provisions: SP A3, SP A7, SP B77, SP N34, SP T10, SP TP2, SP TP7, SP TP13
Source: 49 CFR §172 (15 June 2026)

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Trimethylchlorosilane

Trimethylsilyl chloride, also known as chlorotrimethylsilane, is an organosilicon compound (silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry Wikipedia

Substance Data

Source: PubChem

CAS-Number

75-77-4

Flash Point

—

Boiling Point

—

Emergency Response Guide No. 155

Hazardous Materials Table

Source: 49 CFR §172 (15 June 2026)

(3) Hazard class

3
Flammable liquids

(4) Identification number

UN 1298

(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.

For combination packagings, if glass inner packagings (including ampoules) are used, they must be packed with absorbent material in tightly closed rigid and leakproof receptacles before packing in outer packagings.

Browse special provision A3

Steel packagings must be corrosion-resistant or have protection against corrosion.

Browse special provision A7

B77

Other packaging are authorized when approved by the Associate Administrator.

Browse special provision B77

N34

Aluminum construction materials are not authorized for any part of a packaging which is normally in contact with the hazardous material.

Browse special provision N34

T10

Minimum test pressure (bar)	4
Minimum shell thickness	6 mm
Pressure-relief requirements	§ 178.275(g)(3)
Bottom opening requirements	Prohibited

Browse special provision T10

TP2

a. The maximum degree of filling must not exceed the degree of filling determined by the following:
TP2a

Where:
t_r is the maximum mean bulk temperature during transport,
t_f is the temperature in degrees celsius of the liquid during filling, and
α is the mean coefficient of cubical expansion of the liquid between the mean temperature of the liquid during filling (t_f) and the maximum mean bulk temperature during transportation (t_r) both in degrees celsius.
b. For liquids transported under ambient conditions α may be calculated using the formula:
TP2b

Where:
d₁₅ and d₅₀ are the densities (in units of mass per unit volume) of the liquid at 15 °C (59 °F) and 50 °C (122 °F), respectively.

Browse special provision TP2

TP7

The vapor space must be purged of air by nitrogen or other means.

Browse special provision TP7

TP13

Self-contained breathing apparatus must be provided when this hazardous material is transported by sea.

Browse special provision TP13

(8) Packing Authorizations (§173.***)

(8A) Exceptions	None
(8B) Non-bulk	206	see 49 CFR §173.206
(8C) Bulk	243	see 49 CFR §173.243

(9) Quantity Limits

(9A) Passenger aircraft/rail	Forbidden
(9B) Cargo aircraft only	5 L

(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

40	see 49 CFR §176.84
53	see 49 CFR §176.84
58	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 0072	Cyclotrimethylenetrinitramine, wetted or Cyclonite, wetted or Hexogen, wetted or RDX, wetted with not less than 15 percent water by mass	1.1D
UN 1297	Trimethylamine, aqueous solutions with not more than 50 percent trimethylamine by mass	3
UN 0483	Cyclotrimethylenetrinitramine, desensitized or Cyclonite, desensitized or Hexogen, desensitized or RDX, desensitized	1.1D
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