I have an alibi and I have much better places to play with my chemistry set than next to a freeway and bicycle trail:

Authorities are searching for the person or people responsible for setting off an improvised explosive device (IED) on a bicycle path that runs parallel to I-205 last night.

The Clackamas County Sheriff’s Office said the device was ignited on a bike path that runs along the highway near Strawberry Lane on the west side of the highway. A sheriff’s deputy was driving southbound on the highway around 9:30 p.m. when he witness a flash and a plume of light that stretched across the highway.

It's crap like this that will get Tannerite and Target Master banned.