Jeb Bush called in the Florida National Guard to help fight wildfires that have scorched thousands of acres and blanketed highways with thick smoke, contributing to collisions that have killed four people.

Putting out hot spots along Pioneer Trail is a firefighting crew from the Jacksonville Fire Dept. from left are Steve Brunson, Jimmy Osborne and James Giffen near the Sugar Mill Estates in New Smyrna Beach, Fla., Monday, May 8, 2006. Smoldering brush fires kept about 1,000 people from their homes early Monday, and the heavy smoke shut down parts of Interstate 95 between Daytona Beach and the Cape Canaveral area. [AP]

Portions of Interstate 95 were scheduled to be shut down early Tuesday in Brevard and Volusia counties, where brush fires have consumed more than 8,000 acres.

Officials are tracking about 50 active wildfires throughout the water-parched state, and Bush said lightning was probably not to blame for most blazes.

"The likelihood is most of these fires have been created by either negligence or people doing harm," Bush said.

The governor declared a state of emergency Monday night, deploying aviation units from the Florida National Guard, and met with some of the 155 firefighters working to contain a fire in New Smyrna Beach that has consumed about 1,300 acres since Sunday and destroyed three homes.

"We want to make sure that the residents of these communities are safe and that we isolate these fires as soon as possible," Bush said. "We are a tinder box right now. We had a little bit of rain but not enough to give people assurances that we are not going to have more fires."

About 1,000 residents were ordered to evacuate Sunday in New Smyrna Beach as the fire approached their homes.

Avia Toney was relieved Monday to find her house spared. She fled the neighborhood only when she saw fire approaching through the woods across a nearby fairway.

"It was right at the edge of the woods," she said. "Ashes were falling. It was black and ugly."

Neighbor Mary Bradfield took her cat, Betsy, to safety at a friend's house, but her husband Dick refused to evacuate.

"I didn't want to lose my home," he said Monday. "If it got really dangerous, I would have left."

The fire was 70 percent contained late Monday, but authorities warned it was far from under control. Two firefighters were treated for minor injuries.

"There's a lot of fuel all the way around the edge of this fire. If the wind changes, you can have fire again, fast," said Volusia County Sheriff

Ben Johnson.

Officials advised motorists to find alternate routes around the fires since smoke has been settling on roadways, contributing to collisions.

Portions of State Road 80 and U.S. 27 in western Palm Beach County were closed for three hours Monday morning after smoke from brush fires burning in Broward County settled with fog over the roadways.

The low visibility contributed to four crashes that killed two people and injured 19 passengers on a bus, authorities said. Authorities blamed a five-vehicle collision in Volusia County early Sunday that killed two people on low visibility caused by smoke blending with fog.

More than 2,200 wildfires have burned over 44,000 acres in Florida since Jan. 1, according to the state Division of Forestry.

"The state as a whole is just extremely dry right now," said Jim Brenner, fire management administrator for the state Division of Forestry. "These fires are consuming everything. And it's not over by any stretch of the imagination."