A state investigation into the wildfire linked to last month's massive crash on Interstate 4 didn't find "any evidence of criminal violations or gross negligence," according to a report released Tuesday.
"It appears everything that was supposed to be checked off was checked off," said state Agriculture Commissioner Charles Bronson, who oversees the Division of Forestry, which conducted the investigation. "It was just an unusual set of circumstances that this fire got out."
A chain reaction of collisions on the shrouded interstate killed five motorists, including two from Tampa, in a 70-vehicle pileup.
Some crash victims still blame the state employees who set the fire, so the question of whether the state was at fault is likely to end up in court.
Employees of the state Fish and Wildlife Conservation Commission set a 10-acre controlled burn on the Hilochee Wildlife Management Area in Polk County on Jan. 8 after checking weather reports from the Division of Forestry and the National Weather Service. Those weather predictions said the humidity in the area would remain above 60 percent.
However, about 45 minutes after the controlled burn started, the humidity plunged below 30 percent, the wind picked up and the fire became a 500-acre wildfire that continued burning into the next day.
Forecasters say the wildfire's smoke mingled with early morning fog on Jan. 9, leading to a string of wrecks that killed five, injured 38 and closed a 14-mile stretch of Central Florida's main east-west highway for more than a day.
As the original controlled fire burned, it would have dried the air around it, allowing the drier upper-level air to drop down at that location. That's how the humidity dropped so quickly, leading to the uncontrollable spread, forecasters said.
"Unfortunately, the weather conditions in the area of the burn deteriorated very fast," Bronson said.
The results of the investigation were "exactly what we were expecting," said Fish and Wildlife Conservation Commission regional biologist Jeff McGrady.
Both he and Bronson said the investigation did not indicate the need to change any procedures for controlled burns.
Bronson questioned whether the smoke from the fire played any role in the I-4 crashes, noting that the wind may have been blowing the smoke away from the highway.
However, that part of the investigation is in the hands of the Florida Highway Patrol. The Highway Patrol released a preliminary 120-page crash report Monday for insurance companies to use for claims. But it doesn't address the smoke.
Instead it simply documents each collision, noting which vehicles struck each other. The report cites careless driving as a factor in one 10-vehicle crash, but a final, more detailed report won't be ready for months.
At this point, the state troopers who are investigating the crashes aren't willing to say whether the smoke was a factor in the blinding conditions.
"All of our troopers are attributing the crash to fog. That's based on the weather reports," said Trooper Larry Coggins. He said a number of motorists who drove the highway before the crashes smelled smoke but didn't see any. But the first drivers who crashed ran into sudden fog. "All of a sudden it went completely white," he said.
As for whether the smoke contributed to the pileup, Coggins would only say, "Right now the case is under investigation. We've got a long way to go on the case. We'll just see where it goes."
Federal forecasters are sticking with their original analysis from Jan. 9 that smoke from the fire mixed with fog to blanket part of Polk County in zero-visibility conditions.
"Whenever fog and smoke interact, you're going to have a much denser layer of fog and smoke in the area than when one of the two are absent," said Brian LaMarre, meteorologist in charge of the National Weather Service's office in Ruskin, who was interviewed by the forestry investigators.
Particles in the smoke give water vapor in the fog something to cling to, making it thicker, "and that's why you get a lower visibility," LaMarre said.
He added that a temperature inversion kept the fog and smoke low to the ground. When there's a lack of wind and the higher atmosphere is warmer than the air near the ground, an inversion of cool, heavy, moisture-laden air occurs.
"An inversion keeps things trapped, almost like putting a lid on top of a cup. When it comes to fog and smoke, it's just going to spread out," he said.
LaMarre said the Weather Service had been forecasting dense, patchy fog in Polk County on that morning.
Some crash victims have retained attorneys who have already notified the state of their intent to sue.
"In this case, it appears to be rather obvious that there is liability. It certainly isn't the sharpest knife in the drawer who decided to burn on this morning, with this wind direction and with this type of temperature inversion," said Bartow lawyer Neal O'Toole, who has three clients who were in the accidents.
However, he acknowledged that the case is complex: "What makes it complicated is not only the collisions that occurred between the vehicles, but the unfortunate combination of circumstances that contributed to that - the issue of the burning, the government's potential liability and the unusual weather conditions."
State law limits the government's liability to $200,000 per incident, so lawyers may end up suing trucking companies instead because trucks are required to have large insurance policies. At least six semitrailers burned in the crash, and several of the five people who died burned to death.
"The heavy-hitting plaintiff's attorneys won't want to fool around with trying to get money from the state. They're going to be targeting the deep-pocketed defendants, the big trucking companies. That's cynical, but that's how it works," said Tampa lawyer Scott McMahon, who defends trucking companies for a living.
"This is going to be an investigative, insurance and legal morass that is going to drag on for many, many years," he said.