An investigation of a radiation release nine days later that contaminated 17 workers is expected in a few weeks.
The report was previewed just hours after the contractor that runs the site confirmed it had demoted WIPP President Farok Sharif.
Wyka said the investigation of the truck fire did not reveal exactly what sparked the blaze, but he said the old truck that was hauling salt had a buildup of oil and other combustible materials as well as active leaks.
The fire probably started about 30 minutes before the driver saw the orange glow from the engine compartment and jumped out to try to extinguish it, he said. But the automatic fire-suppression system that might have detected the heat earlier was not active, Wyka said, and the fire extinguisher the driver sprayed on the truck apparently didn't work.
While Wyka praised the 86 workers who were underground when the fire started around 11 a.m. on Feb. 5 for their response, he said a number of systems failed. For example, he said emergency strobe lights were not activated for five minutes, the command-center response was lacking and the investigation showed emergency training drills were inadequate.
Six workers were treated for smoke inhalation after the fire.
"We were pretty lucky that day," he said. "... Despite all the safety systems that sort of let them down, the workforce down in the mine that day was very calm, collected and in many ways heroic."
Wyka said the workers "did everything they could" to notify colleagues to get out, even before the evacuation alarm sounded. "Some stayed behind to make sure everyone got in the elevator to get out."
The biggest lesson, he said, is about the mindset at the site.
"This is not just a mine, not just an operating nuclear facility — this is both," Wyka said, noting that trucks used in the part of the mine where waste is hauled are kept much cleaner than the old trucks used to haul salt in the tunnels. They also have active fire-suppression systems.
Joe Franco, who runs the Department of Energy's site office at WIPP, choked up as he took the stand at the meeting, telling the community that at first he took the findings personally.
"It's one of those things, being part of the family, one of those things that's a little tough," he said. "But I think what's important (is) we definitely got away with not ... having anyone seriously hurt. So we need to learn from that. It is what I wanted to hear, and I wanted the truth. We don't need any sugar-coating."
WIPP is the nation's only deep underground nuclear waste repository and a cornerstone of the Energy Department's $5 billion-a-year program for cleaning up waste scattered at federal labs across the country from decades of making nuclear bombs.
Waste shipments to the dump were halted after the truck fire. Nine days later, a radiation release shuttered all operations.
In a statement Thursday, URS Corp. said Sharif has been replaced by Bob McQuinn as president and project manager of the Nuclear Waste Partnership.