Almost four miles of underground tunnels link Iowa State’s buildings, but they aren’t a good escape route anymore.

Capt. Rob Bowers of the Department of Public Safety said at least one computer heist was pulled off through the steam tunnels during the summer of 1999.

Today, he said, the tunnels are wired with security devices, alerting DPS whenever a thrill-seeker intrudes.

In fact, it isn’t easy getting into the tunnels anymore. The days of gaining access through almost any manhole on campus are long gone.

But Bowers said DPS still has to cope with explorers “a couple of times a year.”

Explorers find the usual spider webs, bugs and occasional bumble bee sucked down through the ventilation units when they head into the tunnels. Portions of the steam tunnel are only 3 feet by 3 feet and wet with ground water and leakage between fused pre-cast blocks.

“The biggest thing is if you are not familiar with them, they can be a very dangerous place,” Bowers said. “The lights are off at night, and there are temperature variances. You can be walking around and be very comfortable. Then, suddenly it becomes very, very hot to your senses.”

Mike Murray, engineer for Facilities Planning and Management, said few buildings have human access doors to the tunnels. Only the steam and its condensate, or water, are allowed to enter and exit.

A blinking red light, mounted in the top corner of the entrance, denotes a security system. They are placed in various areas in the passageways and are maintained by DPS, Murray said. On average, he said it would take two to three minutes for DPS to respond to an alarm in the tunnels.

Of the four miles of tunnels below the campus, only a small portion are open for the occasional tour for the press or the eager engineering student.

A typical tour of the steam tunnels starts in room 74 of Town Engineering, through a locked metal door which latches shut with a bang. A small metal ladder leads to a door about three feet tall with no knob, only a lock. It’s the only way out, and it exits into the College of Design.

Some sidewalks on campus are actually the roof of the tunnel, Murray said, but wouldn’t specify which for security reasons.

“Currently we do not make the tunnel tops part of the sidewalks because of relandscaping,” he said.

Steam rushes through the pipes leaving the power plant at 400 degrees Fahrenheit and travels into the buildings on campus to provide heat, he said. Even with layers of insulation, the pipes are still warm to the touch. A smaller white pipe runs above the steam pipe to take the condensate back to the plant to be reheated.

“The boiler makes steam like a tea kettle does – it goes to campus, is used by giving up its heat to the buildings and then condenses like steam on a cold window,” Murray said. “After it condenses, it returns to the power plant.”

Despite rumors, the tunnels are not abandoned. Murray said he makes a trip below ground to do routine checks about once a week.

“I rap on the concrete to make sure it’s still sound and I look for leaks,” he said.

The gothic arch design used in many buildings on campus, such as the south end of Friley Hall, resembles the first tunnels built on campus. Murray said the tunnels were built using an Arched Brick technique in the 1890s and run mainly below central campus.

Construction and design of the tunnels were then upgraded to a reinforced concrete rectangular structure around the year 1914, he said.

In the 1970s and ’80s, underground construction crews began to bring in pre-cast tunnels which are fused together on site, Murray said. Steam tunnels between Town Engineering and the College of Design were constructed using a cast-in-place construction and are much like an all-white, rectangular hallway.

The most recent steam-tunnel construction was completed in 1997 when Howe Hall was built. It serves Howe Hall, Beyer Hall and the Student Health Center.

“I believe I have been through all of the tunnels at some point,” Murray said. “I like the arched design because they have held up well and are not like you would see now.”