Investigators are trying to figure out if a three-alarm fire at a West Jordan, Utah, lumberyard was eco-terrorism (search).

The blaze burned dangerously close to a nearby strip mall and caused $1.5 million in damage to the Stock Building Supply (search) storage building, which had lumber, flat boards and pallets inside.

Federal investigators say those are targets of the Earth Liberation Front (search), or "ELF," an eco-terrorism group with a history of destroying businesses in the name of the environment. 

"They're engaged in a lot of different activities directing terrorist activities toward these type of establishments," Rick Mey of the FBI told Fox News.

Investigators are tracking a fax received by a Salt Lake City radio station with the heading "ELF" that claimed responsibility for the attack. The message blamed the Stock Building Supply company for failure to repair forklifts that have diesel engines. The message claimed the engines "destroy the ozone and pose a serious health risk to nearby humans and living animals."

Through the years the Earth Liberation Front claims to have caused $100 million in damage. In 1988, members torched a new multimillion-dollar lodge at Colorado's Vail ski resort (search).

Now Utah authorities are on standby: In Tuesday's fax, the group identified three more potential targets in the Salt Lake City area including another lumberyard, the Kennecott Cooper Mine (search) and a Hummer dealership.

Go to the video box at the top of this story to watch a report by Fox News' Carol McKinley.