Who was behind the laughing powder attack, and what was it meant to accomplish?

Reinderdijkhuis on Aug. 28, 2012

We'll be answering some reader questions in the next few episodes. The formatting features on Drunk Duck don't lend themselves to this as well as the functionality on the main website, so please feel free to visit the main ROCR site, where this was posted on February 23, 2005.
Today's reader question is from Geir, who asked:
Who was behind the laughing powder attack, and what was it meant to accomplish?