Working without a net -- but with plenty of safety gear -- two workmen clambered to the top of the Heating Plant smokestack at Montana State University on Wednesday to start tearing down the landmark, brick by brick.

"Every job we go on is dangerous," said Dan Auten, 45, who works building, demolishing, inspecting and repairing smokestacks from Louisiana to California for Pullman Power of Kansas City. "Any time you're several hundred feet in the air, it's dangerous."

The five Pullman crewmen have to wear blue hard hats and be tied off to safety cables and double lanyards 100 percent of the time.

The smokestack was designed by renowned Bozeman architect Fred Willson 81 years ago and is being demolished despite its graceful appearance and historic significance.

Since the high-pressure boilers that heat the entire campus were converted from burning coal to natural gas in 1995, the smokestack has been obsolete.

But the main reason for demolition is that the stack could crash in an earthquake. Worst-case scenario: Falling bricks could cause the plant to explode in the middle of winter, leaving MSU with no heat for months, requiring students be sent home and millions of dollars in tuition refunded.

"Most of us at the university would really have liked to find a way to eliminate the risk without taking the stack down," said Bob Lashaway, MSU facilities director. "We're reluctantly reconciled to this as the way it has to be."

Two engineering firms investigated what it would take to make the stack earthquake-safe. They concluded that even spending $350,000, they couldn't guarantee that it wouldn't fall down.

The Yellowstone region is a hotbed of seismic shaking, like the deadly 1959 earthquake that created Quake Lake. Steel bands were wrapped around the smokestack after that earthquake.

Demolition will cost $88,990. At the request of the state historic preservation office, a plaque will be placed outside the Heating Plant recognizing the landmark and the stack's removal.

On Wednesday workmen were wrapping a bracket cable around the top of the stack to support scaffolding. Then they plan to raise a debris chute, so bricks can be safely lowered to the ground. Jackhammers will be used to take the stack apart.

On Friday a helicopter will remove the metal rain cap on top of the stack. It will be replaced once the stack is shortened to the level of the plant's roof. The whole job should take six weeks.

Two pallets of facing bricks will be saved for repairs. Two pallets of fire bricks will be used to build a kiln at the new art studio for MSU graduate students, the former swine barn.

Auten said he enjoys his work and doesn't mind being up high.

He glanced up. "We usually don't take down a stack this pretty."