Derailment in Martinez: the nightmare no one wants

Early this morning, at least two tank cars carrying liquid petroleum gas (LPG) derailed while backing into the Shell Refinery in Martinez, CA.  (See brief KTVU News coverage.)

Thank our lucky stars that those tank cars backing into the refinery did not tip over or leak!  Had they done so, and a spark ignited a fire, the accident might’ve resulted in a Boiling Liquid Expanding Vapor Explosion, or “BLEVE” (blɛviː/ BLEV-ee).

Sharon Kelly described a BLEVE this way on DeSmogBlog: “As liquids in a metal tank boil, gasses build up, pressurizing the tank even despite relief valves designed to vent fumes. Tanks finally explode, throwing shrapnel great distances, and spitting out burning liquids that can start secondary blazes.”

BLEVEs were responsible  for the massive degree of destruction and loss of life in Lac Magantic, Canada.  If those Martinez tank cars had caught fire and erupted, the whole Shell Refinery might’ve blown up!  Downtown Martinez, the AMTRAK station, and the 680 freeway might’ve been threatened.

Photos of the derailed cars show the 4-digit Hazardous Material Identification Placard: 1075.  The Emergency Response Guidebook, published by the U.S. Dept. of Transportation Pipeline & Hazardous Materials Safety Administration identifies the code for 1075 on p. 31 as one of the following flammable materials:

Butane, Butylene Isobutane, Isobutylene, Liquefied petroleum gas, LPG, Petroleum gases, liquefied Propane Propylene.

This is EXTREMELY dangerous.  On p. 170 of the Emergency Response Guidebook, emergency responders are cautioned:

In fires involving Liquefied Petroleum Gases (LPG) (UN1075); Butane, (UN1011); Butylene, (UN1012); Isobutylene, (UN1055); Propylene, (UN1077); Isobutane, (UN1969); and Propane, (UN1978), also refer to BLEVE – SAFETY PRECAUTIONS (Page 368).

BLEVE is defined : “A boiling liquid expanding vapor explosion (BLEVE, /ˈblɛviː/ BLEV-ee) is an explosion caused by the rupture of a vessel containing a pressurized liquid that has reached temperatures above its boiling point.”

Page 368-369 of the Emergency Response Guidebook reads as follows:

BLEVE (Boiling Liquid Expanding Vapor Explosion)
The following section presents, in a two-page format, background information on BLEVEs and includes a chart that provides important safety-related information to consider when confronted with this type of situation involving Liquefied Petroleum Gases (LPG), UN1075. LPGs include the following flammable gases: Butane, UN1011; Butylene, UN1012; Isobutylene, UN1055; Propylene, UN1077; Isobutane, UN1969; and Propane, UN1978.

What are the main hazards from a BLEVE?
The main hazards from a propane or LPG BLEVE are:
– fire
– thermal radiation from the fire
– blast
– projectiles
The danger from these decreases as you move away from the BLEVE centre. The furthest reaching hazard is projectiles.