The van apparently tried to pass another truck on a curve and crossed the double-yellow line before it collided head-on with the truck Sunday morning, Malheur County Undersheriff Brian Wolfe said.
It took more than seven hours for the section of remote eastern Oregon highway to reopen, once authorities recovered the bodies and highway crews shoveled ash and mangled debris onto trucks.
The firefighters were identified as Ricardo ``Ricky'' Ruiz, 19; Mark Ransdell, 23; Jesse James, 22; David Hammer, 38; Leland Price Jr., 27; Paul Gibson, 25; Richard B. Moore II, 21; and Jeff Hengel, 21.
The men worked for First Strike Environmental, a contract firefighting company and all were from Oregon.
``These were all fine young men who had worked together for two years,'' First Strike president Robert Krueger said in a statement. ``They were closer than most and the hole they leave is enormous.''
Hengel's father, Brian Hengel, said his son loved firefighting and they had spoken shortly after the crew crossed into Oregon.
``He was doing it to make money to pay off his school bills and to pay off the truck I got for him,'' the elder Hengel said.
The two occupants of the Swift Co. tractor-trailer were able to free themselves and were taken to a hospital with dislocations and burns, Wolfe said.
Joy L. Nicholson, 39, was listed in good condition Monday, while Stephen Anthony Nicholson, 37, was treated and released, according to a hospital spokeswoman. Both are from Ogden, Utah.
The crash, about 15 miles west of Vale, was under investigation.
The van had been traveling with another First Strike van and a truck. Both those vehicles were about six miles ahead and did not see the crash, First Strike spokeswoman Leslie Habetler said.
First Strike has been in business for more than 15 years and keeps about 200 firefighters on call during forest fire season. More than 90 percent of the privately contracted fire crews in the United States are based in Oregon.
Fire coordinators said the van that was struck was coming back from a wildfire in the Boise National Forest about 25 miles northeast of the town of Cascade, Idaho.
Before Sunday, 19 firefighters assigned to wildfires had died on duty this year, according to Tracey Powers, spokeswoman for the National Interagency Fire Center in Boise. Nine died in motor vehicle or aviation accidents, three died in fires, six died of illnesses and one died when a tree fell on his tent.