According to AP, at least one of the bombs used in the Boston Marathon was made with a pressure cooker:

WASHINGTON (AP) — The explosives used in the deadly Boston Marathon bombing were contained in 6-liter pressure cookers and hidden in black duffel bags on the ground, a person briefed on the investigation told The Associated Press on Tuesday.

We have at least two of those things at El Castillo Gonzalez and I am well versed in their regular use. They are amazing items to use since they exponentially accelerate rate of cooking without compromising flavor. Whatever takes hours in a crock-pot, takes minutes in a pressure cooker.

However, keyword here is pressure. Accidental explosions with pressure cookers are very few and far between, but when they happen they are catastrophic. They usually happen because the user has disable the double security measures that come with the cooker by tampering with them or not checking them and maintaining them. When I was a kid, I remember seeing a report on the news about a small pressure cooker accident that left a 4 foot hole on an outside wall (made of cement blocks,) a destroyed stove, a kitchen that needed total remodeling and fortunately no casualties.

So if the report from AP is accurate, I can see how the horrendous damages inflicted on the victims happen. Beside any shrapnel added to the device itself, the flying pieces of metal coming out of the cooker itself made for very nasty cutting devices.

Here is a DHS Report on Pressure Cooker IEDs if you care for it. BTW, dear DHS, we use ours for cooking mostly beans, chick peas and making beef or pork stews. Mom would have a fit if they were used for any other purposes.

PS: If you feel like give pressure cooking a try, buy PRESTO and I particularly favor the steel ones. I am just not comfy with the ones made of aluminum.