SMITHFIELD, R.I. – The last of the rubber hit the road Wednesday.

A truck removed the final load of 6 million tires that had been discarded on a site once used as a toxic waste dump and formed a pile so big, pilots flying into Providence once used it as a landmark.

Believed to have been the second-largest tire pile in the nation, behind one in Westley, Calif., if it had caught fire it would have burned for months, state officials said.

“This was a man-made disaster waiting for a time to happen,” said Superior Court Judge Frank Williams, who presided over a tangle of lawsuits surrounding the 25-acre site.

Last year, Williams ruled the state could tap into an oil-spill recovery fund to finish the tire cleanup, which took 31/2 years.

The last of the tires will be trucked to Maine to be burned in pulp mills or used for road material.

Authorities said lax regulations allowed property owner Billy Davis to operate a chemical and used tire dump on the site in the 1970s. He thought they would be a source of fuel and income someday.

Davis, known for deriding government regulators as morons and patrolling the dump with a gun, estimated the pile held more than 30 million tires.

The figure is now believed to be about 6 million.

A woman who answered the phone at Davis’ home said he was not available for comment. Davis had earlier said nature would clean up the site over time.

Firefighters didn’t share his optimism. The state was prepared to bring in Texas oil-well firefighters, the Coast Guard’s Atlantic Strike Team and 600 National Guardsmen to help local firefighters if a blaze started. Their efforts would have cost $2 million a day.

“All it takes is one lightning strike,” fire Chief Kenneth Venables said.

State environmental technician Donald Squires was one of two people who worked at the site daily. At times, he had to forgo the removal equipment and pull out tires by hand. Some piles stood 25 feet high.

“There were tires in between rocks, under trees. There would be tires rolling all over the place,” Squires said. “It’s very hot, dusty. You have humidity, then there’s the mud in the spring, then in the winter it’s cold.”

The chemicals on the site compounded the problem, contaminating groundwater a mile away. The U.S. Environmental Protection Agency had to build a $2 million water line for neighbors.

The EPA has allocated $55 million to rid the land of toxins, but significant cleanup remains. Contractors have removed 1,000 drums of waste chemicals and 10,000 small containers of lab chemicals.

They also have “cooked” 43,000 tons of contaminated soil to filter out pollutants. The cleaned soil is then spread back over the ground.

They expect to clean another 15,000 tons of soil before finishing next summer.

The cost of the entire cleanup – shared among the state, the EPA, Davis and private businesses – is estimated to be about $100 million, Attorney General Sheldon Whitehouse said.

Davis still faces financial penalties and the dump remains a barren patch in the midst of this heavily forested area 11 miles north of Providence.

“This is a victory for everyone who has fought to get these tires removed, but this place is still an environmental disaster,” Whitehouse said.