HazMat Tool — substance information
3-Methyl-1-butene
HMT 15 June 2026- UN / ID
- UN 2561
- Hazard class
- 3
- Packing group
- I
- ERG guide
- ERG 128
- Special provisions
- SP T11, SP TP2
- Source
- 49 CFR §172 (15 June 2026)
3-Methyl-1-butene
Isoamyl acetate, also known as isopentyl acetate, is an ester formed from isoamyl alcohol and acetic acid, with the molecular formula C7H14O2. It is a colorless liquid that is only slightly soluble in water, but very soluble in most organic solvents. Isoamyl acetate has a strong odor which is described as similar to both banana and pear. Pure isoamyl acetate, or mixtures of isoamyl acetate, amyl acetate, and other flavors in ethanol may be referred to as banana oil or pear oil Wikipedia
| Emergency Response Guide No. 128 |
Hazardous Materials Table
Source: 49 CFR §172 (15 June 2026)(3) Hazard Class3Flammable liquids |
(4) Identification number |
(5) Packing Group |
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(6) Labels |
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(7) Special Provisions (§172.102)
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| T11 | |
|---|---|
| TP2 |
(8) Packing Authorizations (§173.***) 
| (8A) Exceptions | None | |
|---|---|---|
| (8B) Non-bulk | 201 | see 49 CFR §173.201 |
| (8C) Bulk | 243 | see 49 CFR §173.243 |
(9) Quantity Limits 
| (9A) Passenger aircraft/rail | 1 L |
|---|---|
| (9B) Cargo aircraft only | 30 L |
(10) Vessel stowage 
| (10A) Location | |
|---|---|
| (10B) Other | n/a |
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![]() |
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3 ![]() | ||||||||||||||||||
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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. |

