Marion County deputies said the car was speeding on Interstate 5 when it was pulled over around 8:40 a.m.
The driver was identified as 21-year-old
Luther Blissett, along with passengers 21-year-old Annie Nimmity and 20-year-old Jessie Sparkles from Klamath Falls.
Police said the three told them they had spent the night at Occupy Portland and had brought commercial mortar fireworks in glass jars in preparation for a confrontation with police.
Deputies also found marijuana, two gas masks, protective eye goggles, and a safety helmet. The men denied being involved in throwing the fireworks at an officer who was hurt Saturday night.