Molten Sulfur Release

Sulfur car derailment Florida

As we have discussed in earlier posts, approximately 6% of the freight cars that transit Ashland carry ‘highly hazardous chemicals’. These are materials that are flammable, explosive or toxic (often a combination of these three). And many of these cars carry elemental sulfur.

Today (2017-11-27) a CSX freight train derailed in Lakeland, Florida. It is reported that several cars rolled over and that four of those cars contained molten sulfur. There was a significant release of sulfur and there appears to be considerable damage. There are no reports of injuries.

Elemental sulfur comes from oil refineries. The crude oil that they receive contains sulfur compounds that need to be removed in the early stages of the refining process. These compounds are converted to sulfur, which is then loaded as a liquid into tank cars. These are transported to sites were the sulfur is used to manufacture many chemicals, including the sulfuric acid used in car batteries.

The melting point for sulfur is 115C/239F — and it is transported at a higher temperature than this to prevent it from solidifying in the cars. Which means that it is hot — much hotter than boiling water. (In the Bible it is referred to as Brimstone).

The image below shows the NFPA 704 Diamond for elemental sulfur.

NFPA Diamond SulfurIf there is a spill of sulfur there are three issues to consider.

Toxicity
In its solid form at room temperature sulfur is virtually non-toxic although sulfur dust is a mild irritant to some peple.

Thermal Burns
If someone is close to a sulfur spill they could be badly burned by the hot liquid.

Flammability
Sulfur is flammable. The combustion produces highly toxic sulfur dioxide gas. The following advice is given to firefighters.

If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2016)

What does all this mean for the residents of Ashland?

Well, there is no such thing as a good sulfur spill. However, were there to be a release such as the one in Florida, the sulfur should solidify quite quickly, thus reducing the hazards to do with toxic gases and fire. However, were the release to be in a trench the sulfur would have nowhere to flow. This would increase the risk of fire and the associated production of highly toxic sulfur dioxide fumes. Furthermore, the emergency response teams would have a more difficult time working with a spill in a trench than they would in an open location.

Sulfur car derailment Florida

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