The mood was jovial Tuesday afternoon as military personnel moved “bloodied” local high school students and dummies through a decontamination tent at the Northwest Washington Fair and Events Center.

But officials say their experiences during the drill will come in handy if a major terrorist attack or natural disaster actually hits Whatcom County.

“You can never be too prepared for any disaster, whether manmade or otherwise,” County Executive Pete Kremen said, citing Whatcom County’s proximity to earthquake fault lines, a petroleum pipeline, two oil refineries and Mount Baker, a dormant volcano.

Hundreds of troops from the U.S. Marine Corps and U.S. Army North joined state and local emergency responders dealing with a fake explosion of a tanker truck full of toxic chemicals, pretending it injured hundreds.

If the incident occurred in real life, St. Joseph Hospital would be overrun with patients and local officials could be forced to call the state National Guard or federal military. The goal of the drill was to help local agencies learn when to make that call and how to work with their federal and state counterparts.

The drill also was an opportunity for the U.S. Marine Corps Chemical Biological Incident Response Force to practice its training. Lt. Cmdr. Kevin Kelley said the last time the 350-Marine force responded was 2004, when ricin was discovered in the office of then-Senate Majority Leader Bill Frist.

Marines wearing gas masks hosed off dummies Tuesday and checked for potential contamination on local high school students who were wearing makeup that made them appear injured. Students were then put on backboards and checked for injuries by Lynden Fire Department crews.

The students joked among themselves but otherwise stayed in character.

“You’d think they’d give us a padded cot or something, but we’re laying on lunch tables,” Blaine High School senior Cole Avery said.