Madison fire officials are searching for the cause of a fire late Monday and early Tuesday that destroyed the historic Sigma Phi Epsilon fraternity house at 237 Langdon St.

Fire Department spokesman Eric Dahl said Tuesday afternoon that evidence from the blaze has been sent to the state Crime Laboratory to test for accelerants to determine whether the fire was arson.

UW-Madison Dean of Students Lori Berquam said Tuesday that students who fled the building told her the fire began outside at the back of the house.

Berquam said the students told her they saw smoke in the back and came down the stairs, grabbed a fire extinguisher and opened the back door to try to put out the flames. But "they saw the flames were too mighty for a fire extinguisher. They closed the door and evacuated the building. Simultaneously, a police officer was pounding on the front door."

Fire officials estimated the damage to the three-story building to be at least $750,000, including the contents. According to the 2008 tax assessment, the property is valued at $742,000. Representatives from the national fraternity and its insurance company are expected to be in Madison today to determine whether the house is salvageable, Dahl said.

In the meantime, a contractor will be erecting a temporary fence around the wrecked house to keep anyone from getting injured by broken glass or debris, and the national fraternity has hired private security guards to watch the property, Dahl said.

By Tuesday afternoon, firefighters were wetting down some hot spots and using a thermal imaging camera to verify that no hot spots remained under the debris from collapsed floors and ceilings, Dahl said.

But he said there appears to be little in the house that could be salvaged.

The fire was reported at 11:41 p.m. Monday when Madison Police Officer Angie Dyhr, patrolling Langdon Street, saw a glow in the back of the house.

Fire officials said a good working smoke alarm system allowed the residents of the fraternity to save themselves. The fraternity had 28 residents but Berquam said only 18-20 people were in the house when the fire broke out.

Madison Fire Department spokeswoman Bernadette Galvez said the alarm system in the building had been regularly maintained. "The alarms were sounding," Galvez said. "We didn't have to rescue anyone."

Dahl said it is routine to send ashes and other materials to the crime lab when the cause of the fire is not readily identified.

"They take samples of the area where they believe the fire originated," he said. "After analyzing what's left, many times they can tell if there was an accelerant or not. They can rule out arson or have an indication that it may be arson."

The house has been occupied by Sigma Phi Epsilon since 1995. Built in the early 1890s with two stories, the top levels were added in 1910 by a university professor, according to the chapter's Web site.

The Web site said the house is "remarkably famous for the elaborate woodwork and many surprises within its walls and ceilings."

Chapter Alumni Board President Patrick Kovich told alumni Tuesday that he did not have details on the long-term plans of the fraternity and the house.

"This is a very challenging time for our fraternity," he wrote in a letter. "However, we have recovered from fire before and become stronger because of it. We will rebuild."

This is the second fire at the fraternity house in the nine years.

In June 1999, the house was seriously damaged. In that incident, firefighters arrived to find the front of the house engulfed in flames shortly before 3:30 a.m. All seven occupants got out safely, but the house sustained $500,000 in damage.

Meanwhile, staff from the UW-Madison dean of students office were arranging temporary housing for the students, as well as granting crisis loans and making contact with professors for accommodations on final exams and papers.

Berquam said members of the chapter's alumni board and national chapter are also making temporary and summer housing arrangements for the dozen or so Sigma Phi Epsilon members who had planned to live there during the summer.

In addition:

• The American Red Cross Badger Chapter has provided debit cards to affected students for food and clothing from its disaster relief fund.

• The University Book Store has offered to loan books to affected students, to temporarily replace those lost in the fire.

Sigma Phi Epsilon was also in the news last week, after UW-Madison authorities said they were looking into a possible reverse hazing incident at the fraternity in which human excrement and vomit were dumped on fraternity members.

"At this time, there is no reason to believe the fire is linked to a pending judicial investigation of the chapter," Berquam said.