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Thioglycolic acid

HMT 15 June 2026

UN / ID: UN 1940
Hazard class: 8
Packing group: II
ERG guide: ERG 153
Special provisions: SP A7 SP B2 SP IB2 SP N34 SP T7 SP TP2
Source: 49 CFR §172 (15 June 2026)

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Thioglycolic acid

Thioglycolic acid (TGA) is the organic compound HSCH2CO2H. TGA is often called mercaptoacetic acid (MAA). It contains both a thiol (mercaptan) and carboxylic acid functional groups. It is a colorless liquid with a strongly unpleasant odor Wikipedia

Substance Data

Source: PubChem (HSDB, 22.10.2026)

CAS-Number

68-11-1

Flash Point

126 ° C

Boiling Point

120 ° C

Emergency Response Guide No. 153

Hazardous Materials Table

Source: 49 CFR §172 (15 June 2026)

(3) Hazard class

8
Corrosive liquids

(4) Identification number

UN 1940

(5) Packing Group

(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.

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

Browse special provision A7

MC 300, MC 301, MC 302, MC 303, MC 305, and MC 306 and DOT 406 cargo tanks are not authorized.

Browse special provision B2

IB2

Authorized IBCs: Metal (31A, 31B and 31N); Rigid plastics (31H1 and 31H2); Composite (31HZ1).
Additional Requirement: Only liquids with a vapor pressure less than or equal to 110 kPa at 50 °C (1.1 bar at 122 °F), or 130 kPa at 55 °C (1.3 bar at 131 °F) are authorized.

Browse special provision IB2

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

Minimum test pressure (bar)	4
Minimum shell thickness	§ 178.274(d)(2)
Pressure-relief requirements	Normal
Bottom opening requirements	§ 178.275(d)(3)

Browse special provision T7

TP2

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

Where:
tr is the maximum mean bulk temperature during transport,
tf 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 (tf) and the maximum mean bulk temperature during transportation (tr) 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

(8) Packing Authorizations (§173.***)

(8A) Exceptions	154	see 49 CFR §173.154
(8B) Non-bulk	202	see 49 CFR §173.202
(8C) Bulk	242	see 49 CFR §173.242

(9) Quantity Limits

(9A) Passenger aircraft/rail	1 L
(9B) Cargo aircraft only	30 L

(10) Vessel stowage

(10A) Location

Stowage category “A” means the material may be stowed “on deck” or “under deck” on a cargo vessel or on a passenger vessel.

Source: 49 CFR §172.101(k)

(10B) Other

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.

Hinweis: In der Kompatibilitätstabelle sind Stoffe der Gefahrenklasse 8 nur dann zu berücksichtigen, wenn der Stoff flüssig ist. Derzeit kann HazMat Tool nicht prüfen, ob der Stoff flüssig ist. Dies wird daher hier angenommen. Siehe PHMSA Interpretation #09-0252.

Full segregation table for class 8 · Browse UN entries for this class

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.