Hazard class 4.2

Class 4.2: Spontaneously combustible

Materials that can heat up and ignite on their own in air. Below is every Class 4.2 entry in 49 CFR §172.101 that has a UN/NA number — 79 entries.

ID	Proper shipping name	Class	PG
NA1361	Charcoal briquettes, shell, screenings, wood, etc.	4.2	III
UN1361	Carbon, animal or vegetable origin	4.2	II
UN1362	Carbon, activated	4.2	III
UN1363	Copra	4.2	III
UN1364	Cotton waste, oily	4.2	III
UN1365	Cotton, wet	4.2	III
UN1369	p-Nitrosodimethylaniline	4.2	II
UN1372	Fibers, animal or Fibers, vegetable burnt, wet or damp	4.2	III
UN1373	Fibers or Fabrics, animal or vegetable or Synthetic, n.o.s. with animal or vegetable oil	4.2	III
UN1374	Fish meal, unstablized or Fish scrap, unstabilized	4.2	II
UN1376	Iron oxide, spent, or Iron sponge, spent obtained from coal gas purification	4.2	III
UN1378	Metal catalyst, wetted with a visible excess of liquid	4.2	II
UN1379	Paper, unsaturated oil treated incompletely dried (including carbon paper)	4.2	III
UN1380	Pentaborane	4.2	I
UN1381	Phosphorus, white dry or Phosphorus, white, under water or Phosphorus white, in solution or Phosphorus, yellow dry or Phosphorus, yellow, under water or Phosphorus, yellow, in solution	4.2	I
UN1382	Potassium sulfide, anhydrous or Potassium sulfide with less than 30 percent water of crystallization	4.2	II
UN1383	Pyrophoric metals, n.o.s., or Pyrophoric alloys, n.o.s	4.2	I
UN1384	Sodium dithionite or Sodium hydrosulfite	4.2	II
UN1385	Sodium sulfide, anhydrous or Sodium sulfide with less than 30 percent water of crystallization	4.2	II
UN1386	Seed cake, containing vegetable oil solvent extractions and expelled seeds, with not more than 10 percent of oil and when the amount of moisture is higher than 11 percent, with not more than 20 percent of oil and moisture combined	4.2	III
UN1386	Seed cake with more than 1.5 percent oil and not more than 11 percent moisture	4.2	III
UN1387	Wool waste, wet	4.2	III
UN1431	Sodium methylate	4.2	II
UN1854	Barium alloys, pyrophoric	4.2	I
UN1855	Calcium, pyrophoric or Calcium alloys, pyrophoric	4.2	I
UN1856	Rags, oily	4.2	III
UN1857	Textile waste, wet	4.2	III
UN1923	Calcium dithionite or Calcium hydrosulfite	4.2	II
UN1929	Potassium dithionite or Potassium hydrosulfite	4.2	II
UN1932	Zirconium scrap	4.2	III
UN2002	Celluloid, scrap	4.2	III
UN2004	Magnesium diamide	4.2	II
UN2006	Plastics, nitrocellulose-based, self-heating, n.o.s.	4.2	III
UN2008	Zirconium powder, dry	4.2	I
UN2009	Zirconium, dry, finished sheets, strip or coiled wire	4.2	III
UN2210	Maneb or Maneb preparations with not less than 60 percent maneb	4.2	III
UN2217	Seed cake with not more than 1.5 percent oil and not more than 11 percent moisture	4.2	III
UN2318	Sodium hydrosulfide, with less than 25 percent water of crystallization	4.2	II
UN2441	Titanium trichloride, pyrophoric or Titanium trichloride mixtures, pyrophoric	4.2	I
UN2447	Phosphorus white, molten	4.2	I
UN2545	Hafnium powder, dry	4.2	I
UN2546	Titanium powder, dry	4.2	I
UN2793	Ferrous metal borings or Ferrous metal shavings or Ferrous metal turnings or Ferrous metal cuttings in a form liable to self-heating	4.2	III
UN2845	Pyrophoric liquids, organic, n.o.s	4.2	I
UN2846	Pyrophoric solids, organic, n.o.s	4.2	I
UN2870	Aluminum borohydride or Aluminum borohydride in devices	4.2	I
UN2881	Metal catalyst, dry	4.2	I
UN2940	9-Phosphabicyclononanes or Cyclooctadiene phosphines	4.2	II
UN3088	Self-heating solid, organic, n.o.s	4.2	II
UN3126	Self-heating solid, corrosive, organic, n.o.s	4.2	II
UN3127	Self-heating solid, oxidizing, n.o.s.	4.2	—
UN3128	Self-heating solid, toxic, organic, n.o.s	4.2	II
UN3174	Titanium disulphide	4.2	III
UN3183	Self-heating liquid, organic, n.o.s	4.2	II
UN3184	Self-heating liquid, toxic, organic, n.o.s	4.2	II
UN3185	Self-heating liquid, corrosive, organic, n.o.s	4.2	II
UN3186	Self-heating liquid, inorganic, n.o.s	4.2	II
UN3187	Self-heating liquid, toxic, inorganic, n.o.s	4.2	II
UN3188	Self-heating liquid, corrosive, inorganic, n.o.s	4.2	II
UN3189	Metal powder, self-heating, n.o.s	4.2	II
UN3190	Self-heating solid, inorganic, n.o.s	4.2	II
UN3191	Self-heating solid, toxic, inorganic, n.o.s.	4.2	II
UN3192	Self-heating solid, corrosive, inorganic, n.o.s.	4.2	II
UN3194	Pyrophoric liquid, inorganic, n.o.s	4.2	I
UN3200	Pyrophoric solid, inorganic, n.o.s	4.2	I
UN3205	Alkaline earth metal alcoholates, n.o.s	4.2	II
UN3206	Alkali metal alcoholates, self-heating, corrosive, n.o.s.	4.2	II
UN3254	Tributylphosphane	4.2	I
UN3255	tert-Butyl hypochlorite	4.2	I
UN3313	Organic pigments, self-heating	4.2	II
UN3341	Thiourea dioxide	4.2	II
UN3342	Xanthates	4.2	II
UN3391	Organometallic substance, solid, pyrophoric	4.2	I
UN3392	Organometallic substance, liquid, pyrophoric	4.2	I
UN3393	Organometallic substance, solid, pyrophoric, water-reactive	4.2	I
UN3394	Organometallic substance, liquid, pyrophoric, water-reactive	4.2	I
UN3400	Organometallic substance, solid, self-heating	4.2	II
UN3497	Krill meal	4.2	II
UN3542	Articles containing a substance liable to spontaneous combustion, n.o.s.	4.2	—

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Other hazard classes

Class 1 Class 2.1 Class 2.2 Class 2.3 Class 3 Class 4.1 Class 4.3 Class 5.1 Class 5.2 Class 6.1 Class 6.2 Class 7 Class 8 Class 9

Source: 49 CFR §172.101 via eCFR.gov, current as of Oct 23, 2026. Reference only.