Groundwater tests at a Noyack sand mine and mulch facility have found elevated levels of two metals at the site.
The tests by the Suffolk County Department of Health Services at the Sand Land Mine found 200 times the acceptable level of manganese in the groundwater, and 100 times the acceptable level of iron.
It also found elevated levels of sodium, thallium, nitrate, and ammonia.
The contaminants were found at a depth of 120 feet.
The report called for the mine to stop operations until mitigation plans are put in place.
The attorney for Sand Land says the owners believe in the protection of water quality, while allowing responsible use of the land to provide services for the community.
Tests on wells in the surrounding area found they met safety standards.