Can dry ice in a picnic cooler "cause pressure buildup" and explode????

edited to add the story behind it, and would really like your takes on this:

Container carrying swine flu virus explodes on Swiss train
28 April 2009

Lausanne (Switzerland), April 28 (DPA) A container for transporting swine flu virus samples exploded on a Swiss train, authorities said Tuesday, but stressed that there was no danger to the public.
The container, which was filled with dry ice and carried samples of the H1N1 swine flu virus and was destined for Switzerland's national influenza centre in Geneva, exploded Monday night on board a train.

A laboratory employee had picked up the samples in Zurich to transport them by train to Geneva, but the package exploded near Fribourg and Lausanne, after melting dry ice, which had been wrongly placed, caused a build-up of pressure.The technician had dozed off on a train travelling from St Gallen to Geneva. Near Fribourg the technician heard a muffled pop. Built-up gas from dry ice surrounding the vials had caused the package to explode.

Two people suffered slight injuries, police confirmed, but authorities stressed there was no danger for the public as the virus was not the mutated strain which is suspected to have caused up to 149 deaths in Mexico.

The train was halted for several hours and the 61 passengers on board the affected carriage monitored until an infection could be completely ruled out, police said.

http://www.swissinfo.ch/eng/news_digest/Vials_of_swine_flu_virus_explode_on_train.html?siteSect=104&sid=10627294&cKey=1240904909000&ty=nd

I would doubt it - I don't think coolers would be air tight enough for one thing.

I don't think I've ever even heard of such a cooler.

CO2 expands a LOT as it changes to gas.

I've never seen a cooler that was air tight, not really even water tight if you turn them upside down.

Dry ice creates a lot of gas, true, but it sublimes fairly slowly if it's insulated from direct heat input, which it would be in a cooler.

For example, plastic soda bottles will explode under those conditions, because the plastic ring under the cap provides a tight enough seal, but bottled water bottles will not explode due to their lack of such sealing ring. Even though they're water tight, it's not tight enough.

I could definitely imagine it happening, but it would have to be a pretty unusual cooler.

of them would reach 5 psi before leaking. Most of them now have a friction-fit plastic drain, besides, which would pop off around the same pressure.

And as someone already mentioned, the drain plug would pop open before the cooler itself would blow up.

http://www.baconfire.com/Safety.html

1. Do not store dry ice in closed glass containers. Doing so can cause
pressure build-up and the container will explode.

2. Dry ice is so cold it will burn your skin. To avoid serious burns, do
not handle the ice with your bare hands. Instead, use mitts, gloves, or
towels.

3. Always make sure there is enough ventilation when using dry ice.
This is especially important in small, closed areas (like your car)
because dry ice removes the oxygen from the air and can cause
breathing problems if area is not ventilated properly.

4. Dry ice can be stored in a Styrofoam box or picnic cooler. Never
store in freezer or refrigerator. Protect the ice from the air current by
filling the empty space in your cooler with newspaper and towels to
keep it from sublimating until you are ready to use it. Properly stored
ice can last 2 to 3 days.

5. If you are using the ice to create fog and your container stops
fogging, just change the water because it has become carbonated.

6. If you are using the ice in a beverage, you may drink the beverage,
but be very careful not to swallow any pieces of the dry ice.

7. You must be 18 or older to purchase dry ice from Bacon Equipment
Company and children should always be supervised when handling dry
ice.

/nt