Chemistry - Is there any substance that's a 4-4-4 on the NFPA diamond?

Solution 1:

Answering my own question based on the comments, tert-butyl-hydroperoxide is at least one such chemical. As stated on this MSDS from a government website, it's a 4-4-4, with additional special warning of being a strong oxidizer. The only thing that it does not do that could make the 704 diamond any worse is react strongly with water. It is in fact water soluble, though marginally, preferring to float on top (and therefore traditional water-based fire suppression is ineffective, but foam/CO2 will work).

If anyone else can find a chemical that, in a form that is used in the lab or industrially, is a 4-4-4 that is a strong oxidizer and reacts strongly with water, that's pretty much "as bad as it gets" and they'll get the check.

Solution 2:

Diborane. NIOSH gives NFPA 4-4-4-W:

NFPA 704 4-4-4-W

Solution 3:

Ethyl nitrite is rated 4-4-4 but it does not have anything on the white square. Pentaborane has a good 4-4-4-W. However it's not an oxidizer.

Solution 4:

It seems that diborane (see answer by feetwet) is the only compound rated with H4 F4 R4 code by NIOSH, though there are two substances lacking just a single point to join a 4-4-4-club:

  • picric acid $\ce{(O2N)3C6H2OH}$: NFPA 704 3-4-4;
  • germane $\ce{GeH4}$: NFPA 704 4-4-3.

Solution 5:

Now I'm no chemist (I'm actually a biologist, with a science addiction) But as far as flammability and reactivity especially with water, I would assume some of the alkali metals, especially the heavier ones. Cesium in particular explodes on contact with water.

I would assume that any radioactive isotopes of it would be considered a huge health hazard, due to its analog nature with sodium and other lighter members of it's family.

On that thought, the end Actinides Uranium, Neptunium, and especially Plutonium are all highly hazardous for their radioactivity as well as being heavy metal poisons like lighter analogs such as Lead, Thallium, and Polonium (also lethally toxic due to radioactivity).

The fission metals (if you will pardon the term) are also pyrophoric due to decay heating and when divided will often spontaneously ignite. Admittedly these are all chemical elements, and the properties of a single element is no guarantee on it's action as part of a compound.