HazMat Tool — substance information

Organophosphorus compound, toxic, flammable, n.o.s.

HMT 15 June 2026

UN / ID: UN 3279
Hazard class: 6.1
Packing group: I (multiple — see tabs)
ERG guide: ERG 131
Special provisions: SP 5, SP T14, SP TP2, SP TP13, SP TP27
Source: 49 CFR §172 (15 June 2026)

On this page

Organophosphorus compound, toxic, flammable, n.o.s.

Organophosphorus chemistry is the scientific study of the synthesis and properties of organophosphorus compounds, which are organic compounds containing phosphorus. They are used primarily in pest control as an alternative to chlorinated hydrocarbons that persist in the environment. Some organophosphorus compounds are highly effective insecticides, although some are extremely toxic to humans, including sarin and VX nerve agents. Phosphorus, like nitrogen, is in group 15 of the periodic table, and thus phosphorus compounds and nitrogen compounds have many similar properties Wikipedia

Emergency Response Guide No. 131

Hazardous Materials Table

Source: 49 CFR §172 (15 June 2026)

Packing group I
Packing group II

(3) Hazard Class

6.1
Poisonous Material

(4) Identification number

UN 3279

(5) Packing Group

Comparison View of PG

(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.

If this material meets the definition for a material poisonous by inhalation (see § 171.8 of this subchapter), a shipping name must be selected which identifies the inhalation hazard, in Division 2.3 or Division 6.1, as appropriate.

Browse special provision 5

T14

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

Browse special provision T14

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

TP13

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

Browse special provision TP13

TP27

A portable tank having a minimum test pressure of 4 bar (400 kPa) may be used provided the calculated test pressure is 4 bar or less based on the MAWP of the hazardous material, as defined in § 178.275 of this subchapter, where the test pressure is 1.5 times the MAWP.

Browse special provision TP27

(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

Stowage category “B” means

(i) The material may be stowed “on deck” or “under deck” on a cargo vessel and 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; and
(ii) “On deck only” on passenger vessels in which the number of passengers specified in paragraph (k)(2)(i) of this section is exceeded.

Source: 49 CFR §172.101(k)

(10B) Other

40	see 49 CFR §176.84

Source: 49 CFR §176.84

(3) Hazard Class

6.1
Poisonous Material

(4) Identification number

UN 3279

(5) Packing Group

Comparison View of PG

(6) Labels

(7) Special Provisions (§172.102)

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

T11

Minimum test pressure (bar)	6
Minimum shell thickness	§ 178.274(d)(2)
Pressure-relief requirements	Normal
Bottom opening requirements	§ 178.275(d)(3)

Browse special provision T11

TP2

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

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

TP13

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

Browse special provision TP13

TP27

Browse special provision TP27

(8) Packing Authorizations (§173.***)

(8A) Exceptions	153	see 49 CFR §173.153
(8B) Non-bulk	202	see 49 CFR §173.202
(8C) Bulk	243	see 49 CFR §173.243

(9) Quantity Limits

(9A) Passenger aircraft/rail	5 L
(9B) Cargo aircraft only	60 L

(10) Vessel stowage

(10A) Location

Stowage category “B” means

(i) The material may be stowed “on deck” or “under deck” on a cargo vessel and 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; and
(ii) “On deck only” on passenger vessels in which the number of passengers specified in paragraph (k)(2)(i) of this section is exceeded.

Source: 49 CFR §172.101(k)

(10B) Other

40	see 49 CFR §176.84

Source: 49 CFR §176.84

Packing group comparison

Multiple packing groups apply to this entry. See assignment criteria in 49 CFR §173 Subpart D. Details are in the tabs above; differences are highlighted.

	PG I	PG II
1
2	Organophosphorus compound, toxic, flammable, n.o.s.	Organophosphorus compound, toxic, flammable, n.o.s.
3	6.1	6.1
4	UN 3279	UN 3279
5	I	II
6	6.1, 3	6.1, 3
7	5, T14, TP2, TP13, TP27	IB2, T11, TP2, TP13, TP27
8A	None	153
8B	201	202
8C	243	243
9A	1 L	5 L
9B	30 L	60 L
10A	B	B
10B	40	40

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: The HMR prohibit only those Division 6.1 liquids that meet the definition of a Packing Group (PG) I and Hazard Zone A. See special provision 1 and PHMSA Interpretation #09-0252.

Packages with POISON or POISON INHALATION HAZARD labels, or a POISON label displaying “PG III,” or “PG III” marked next to a POISON label may not be transported with foodstuffs, feed or any other edible material, intended for humans or animals. For exceptions see 49 CFR §177.841(e).

Scope & sources (important)Click to show CFR references

This check evaluates segregation per 49 CFR §177.848. Additional loading/unloading and handling requirements may still apply; see 49 CFR §177 Subpart B (Loading and Unloading):

§177.834 - General requirements
§177.835 - Class 1 materials
§177.837 - Class 3 materials
§177.838 - Class 4 (flammable solid) materials, Class 5 (oxidizing) materials, and Division 4.2 (pyroforic liquid) materials
§177.839 - Class 8 (corrosive) materials
§177.840 - Class 2 (gases) materials
§177.841 - Division 6.1 and Division 2.3 materials
§177.842 - Class 7 (radioactive) material
§177.843 - Contamination of vehicles

Similar substances

UN / ID	Proper shipping name	Hazard class
UN 3017	Organophosphorus pesticides, liquid, toxic, flammable, flash point not less than 23 degrees C	6.1
UN 2784	Organophosphorus pesticides, liquid, flammable, toxic, flash point less than 23 degrees C	3
UN 3018	Organophosphorus pesticides, liquid, toxic	6.1
UN 2783	Organophosphorus pesticides, solid, toxic	6.1
UN 3278	Organophosphorus compound, liquid, toxic, n.o.s	6.1
UN 3464	Organophosphorus compound, solid, toxic, n.o.s	6.1