by yellowcanoe » Fri 13 Dec 2013, 23:33:28
$this->bbcode_second_pass_quote('ROCKMAN', 'C')anoe - I haven't confirmed it but I just read that the feds are allowing more export exceptions. I don't know exactly what happened in the Canadian accident. While oil isn't generally explosive but once it's ignited it burns really hot. One possibility is that some unruptured tankers might have heated up to explosive pressure levels.
It takes time for an unruptured tanker to heat up to the point that you get a BLEVE explosion. I'd guess there was some highly volatile liquid at the top of each tank that could be quickly mixed with air when the tank ruptured which would then cause an explosion when ignited. It will be interesting to see what the Transportation Safety Board report says about the accident.
$this->bbcode_second_pass_quote('ROCKMAN', '
')The odd thing about the story is that all across the US and Canada there are many times more tankers of much more volatile, explosive, corrosive and toxic the crude oil. Consider a very strange accident in S Texas about 40 years ago. A propane delivery truck was rear ended, exploded and shot off like a rocket through a trailer park killing many. And about 10 years ago some locals in Houston got panicky when they found out some tanker trucks carrying napalm was moving thru the area. But napalm is designed to be less volatile and explosive than gasoline. Makes a much better (and vicious) weapon that way. IOW the many tens of thousands of tank trucks delivering gasoline to the stations in Houston every year were much more dangerous. But "napalm" is a much scarier word than "gasoline". Now, because of the accident many Canadians are more scared of trains hauling oil then they are of gasoline hauls.
Yes, most people don't understand (or choose not to understand) the concept of relative risk and you are quite correct in pointing out that other types of materials carried on trains are more dangerous than oil. The Mississauga trail derailment in 1979 resulted in the evacuation of 200,000 people as one of the ruptured cars contained chlorine which could have resulted in a poisonous vapour being spread over a wide area. However, I can't fault people for being concerned about oil trains. The fire and explosions that occured after the derailment in Lac Megantic happened so quickly that roughly 50 people did not have an opportunity to evacuate the area. It wasn't that the buildings were hit by the derailed tank cars, but that the buildings were engulfed in fire so quickly that people didn't have a chance to escape.