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UN identification number

UN1611: Hexaethyl tetraphosphate

As listed: Hexaethyl tetraphosphate, liquid

UN1611 appears 2 times in the Hazardous Materials Table (49 CFR §172.101). Hazard class 6.1, packing group II.

ID numberUN1611
Hazard class6.1
Packing groupII
Label codes6.1

All §172.101 entries for UN1611

Proper shipping nameClassPGLabels
Hexaethyl tetraphosphate, liquid6.1II6.1
Hexaethyl tetraphosphate, solid6.1II6.1

Open any entry for packaging sections, special provisions, air limits and vessel stowage.

What it means

6.1
Class 6.1 — Poisonous (toxic) material. Materials, other than gases, that are toxic to humans if swallowed, inhaled, or absorbed through skin.

Packing group ranks danger within the class: PG II = medium danger.

Label codes (column 6): 6.1 → Poison / Toxic label.

UN numbers are recognized for international and domestic transport.

Example basic description

UN1611, Hexaethyl tetraphosphate, 6.1, PG II

Proper shipping name shown without the table's italic descriptive text. Order per §172.202: ID number, proper shipping name, hazard class, packing group. Example only — add technical names, “RQ”, quantities and other elements your shipment requires.

What to check next

  1. Match the name. Compare your SDS Section 14 to the proper shipping names above and pick the row with your packing group.
  2. Read the special provisions on the entry page (§172.102) — they can add limits or exceptions.
  3. Check packaging — the entry page lists the Part 173 sections for exceptions, non-bulk and bulk.
  4. Labels & placards. Placarding depends on class and quantity — see Table 1 vs Table 2.
  5. Emergency response. Find the response guide for UN1611 in the current PHMSA Emergency Response Guidebook.
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Common questions about UN1611

What is UN1611?

UN1611 is the identification number for Hexaethyl tetraphosphate in the DOT Hazardous Materials Table (49 CFR §172.101).

What hazard class is UN1611?

UN1611 is listed under hazard class 6.1 (poisonous (toxic) material).

What packing group is UN1611?

Packing group for UN1611: II. Where several rows exist, the packing group that fits your material decides which row applies.

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Source: Hazardous Materials Table (49 CFR §172.101), eCFR.gov — current as of Oct 23, 2026. View the official table. Reference only — verify current requirements before shipping.