The equestrian center at West Hills County Park is set to reopen on June 1.

The center has been shut down for nearly three years and off limits to humans and horses.

In August 2016, piles of toxic construction debris were discovered. Several construction companies and the former stable operator eventually pleaded guilty to illegally dumping 11,000 tons of poisonous dirt that contained a cocktail of pesticides, asbestos and other volatile chemicals. In one spot, officials say a 6-foot-high pile of contaminated debris was so toxic that it killed nearby trees.

Suffolk County Executive Steve Bellone says the toxic removal was paid for by the perpetrators.

The Department of Environmental Conservation has since certified that the park is free of contaminants.

The dumping of construction debris and hazardous waste has plagued Long Island for decades. Hundreds of tons of toxic debris have been found in parks, wetlands, playgrounds, private homes and a subdivision for veterans.

Bellone says law enforcement has stepped up efforts to catch, prosecute and fine illegal dumpers.