FYI
DHS Warning on Pressure Cooker IEDs
Pressure Cookers as IED Components
(U//FOUO) Rudimentary improvised explosive devices (IEDs) using pressure cookers to contain the initiator, switch, and explosive charge (typically ammonium nitrate or RDX) frequently have been used in Afghanistan, India, Nepal, and Pakistan. Pressure cookers are common in these countries, and their presence probably would not seem out of place or suspicious to passersby or authorities. Because they are less common in the United States, the presence of a pressure cooker in an unusual location such as a building lobby or busy street corner should be treated as suspicious.[snip]
One of these was used in the May 2010 attack in Times Square
http://publicintelligence.net/ufouo-dhs-warning-on-pressure-cooker-ieds/
Thank you AuntB for the info.