YONGSAN GARRISON, South Korea — Eighteen soldiers and one civilian hid charcoal-covered faces under masks as a healthy dusting of snow drifted onto their chemical protective suits.

An instructor held a hose out for the first of them to take part in Monday’s crucial training — washing a car.

“You know the Army saying, ‘If it ain’t raining we ain’t training?’” said 38th Chemical Detachment’s head instructor Staff Sgt. Terry Bradford. “Snow is just frozen rain.”

It was the last day of training for the detachment’s two-week chemical, biological, radiological and nuclear defense course.

Students from units across the peninsula were set to graduate Tuesday, but not before one last bit of “hands-on” training with a Multi-Purpose Decontamination System — a large green box with hoses on one end leading to a garbage can full of water, and on the other end leading to a high-pressure spraying wand.

The course included training on all decontamination equipment a unit might have, said Sgt. 1st Class Wilfredo Santiago, the detachment first sergeant.

He said that while not every unit had an assigned chemical soldier, most have decontamination and detection gear.

The course ensures that someone in each unit knows how to use and maintain that equipment.

“It’s absolutely essential for every soldier to be prepared for a chemical threat here,” Santiago said. “With our neighbors to the north, proper training is very crucial.”

Soldiers said they believe the training will be useful.

“It’s good for my promotion points,” said Pfc. Daniel Fernandez of the 201st Signal Company. “And it’s also good for saving lives in the future.”

The lone civilian in the class, David Kim, a supply technician for the U.S. Army Corps of Engineers, Far East District, also thought it could be useful. But washing a car in the snow is not something he would normally consider.

“I usually just let ajeossi do it,” he said, using the Korean world for a middle-aged or older man.