The Suffolk County Department of Health Services has been granted full approval to install groundwater test wells at the Sand Land mine in Noyac to monitor the operation’s impact.

Earlier this month, State Supreme Court Justice Joseph Santorelli ruled in favor of county officials in a lawsuit, giving them permission to install the wells on the 50-acre site off Middle Line Highway, which is operated by Wainscott Sand and Gravel.

The industrial sand mine, located in a Special Groundwater Protection Area, also has been used at times since the 1980s as a solid waste processing operation, accepting construction debris, and processing, storing and selling compost and mulch.

The Suffolk County Health Department found metals and pesticides when it did surface testing on a pond on the site in May 2015, and expressed concern that the pollutants could be leaching into the below-ground aquifer that East End residents rely upon for drinking water.

Citizens Campaign for the Environment, an environmental group based in Farmingville, said testing at the site found “contaminants and carcinogens, including chlordane and radio nuclides.” The group also said groundwater testing south of the site in 2015 and 2016 found “the presence of contamination from vegetative waste.”

Last fall, Wainscott Sand and Gravel officials had granted permission for the Health Department to test the groundwater, but then rescinded that permission in October 2016, leading to a warrant and the lawsuit.

“The public’s need for effective enforcement of the [county] to conduct groundwater tests to determine if toxic chemicals from the composting facility in Noyac are entering the groundwater in the area outweigh the respondent’s arguments against the warrant being issued,” Justice Santorelli wrote in the August 9 ruling.

Adrienne Esposito, executive director for Citizens Campaign for the Environment, said she is eager to see the results of the county’s testing. “This is a great decision that reestablishes the county Health Department’s critical role in protecting our drinking water supply,” she said in a statement this week. “We know that compost and mulch operations throughout Long Island cause groundwater contamination, and that Sand Land was accepting these materials for decades.”

Brian Matthews of the East Hampton-based law firm Matthews, Kirst & Cooley, PLLC—who is representing Wainscott Sand and Gravel—did not respond to calls seeking comment. It is unclear whether Mr. Matthews will appeal the court’s decision.

In spring of 2016, the State Supreme Court Appellate Division ruled that Sand Land did not have the right to continue to operate a solid-waste processing facility at the site, upholding a 2012 ruling by the Southampton Town Zoning Board of Appeals. The company was allowed to process and sell whatever was already on site.

However, in September 2016, a flier was circulated by Wainscott Sand and Gravel notifying residents that Sand Land would begin accepting materials such as leaves, brush, grass and wood chips in October—suggesting to some that the facility would resume composting operations that had been prohibited by the previous court decision. It is unclear whether those operations are still taking place.