New York Finalizes MCLs For Three Contaminants of Emerging Concern

On July 30, 2020, the New York State Department of Environmental Conservation (NYSDEC) finalized Maximum Contaminant Levels (MCLs) for three contaminants of emerging concern under the state’s Safe Drinking Water Act. Under the new rules, an MCL of 10.0 ng/L (parts per trillion, or ppt) has been established for PFOA and PFOS, which are members of the PFAS family of chemicals. In addition, an MCL of 1.0 ug/L (parts per billion or ppb) was established for 1,4-Dioxane, a chemical that has been used as a stabilizer in solvents, paint strippers, greases, and wax. New York is the first state in the country to establish an MCL for 1,4-Dioxane.


These new regulations also require public water systems in the state – regardless of size – to regularly test for and monitor these chemicals. All three contaminants have been detected in drinking water systems across the country, yet remain unregulated by the U.S. Environmental Protection Agency (EPA), which is responsible for setting regulatory limits under the federal Safe Drinking Water Act. Once the new regulations are published, systems serving 10,000 people or more will be required to begin testing within 60 days, within 90 days for systems serving between 3,300 to 9,999 people, and within six months for systems serving less than 3,300 people.


New York joins New Jersey as two of a handful of states to set strict MCL limits for PFAS contaminants in drinking water this summer. On June 1, 2020, the New Jersey Department of Environmental Protection (NJDEP) established MCLs of 14 ppt for PFOA and 13 ppt for PFOS. These rules also added PFOA and PFOS to the New Jersey’s list of hazardous substances and sets these levels as formal groundwater quality standards for site remediation activities and regulated discharges to groundwater. In 2018, New Jersey became the first state to adopt an MCL for any PFAS, setting an MCL of 13 ppt for PFNA. The federal government has not established MCLs for any PFAS. To date, New Hampshire and Vermont are the only other states to advance formal MCL drinking water standards for PFAS.

Promulgated State MCLs for PFAS Compounds

New Hampshire – Adopted Regulation: 10/1/19

– PFOA – 12 ppt

– PFOS – 15 ppt

– PFHxS – 18 ppt

– PFNA – 11 ppt


New Jersey – Adopted Regulation: 9/4/18 and 6/1/20

– PFNA – 13 ppt

– PFOA – 14 ppt

– PFOS – 13 ppt


New York – Adopted Regulation: 7/30/20

– PFOA – 10 ppt

– PFOS – 10 ppt


Vermont – Adopted Regulation: 3/17/20

– Sum of PFOA, PFOS, PFNA, PFHxS, PFHpA – 20 ppt


First Environment is actively performing site investigation and remediation activities of regulated PFAS compounds and 1,4-Dioxane at several contaminated sites. We are also performing historical research for past PFAS and 1,4-Dioxane use to assist our clients with potentially responsible party searches, cost recovery, contribution, and toxic tort lawsuits and allocations. In New York state, we are working under an NYSDEC order to remediate PFAS compounds in groundwater via several variations of the GAC technology as both an Interim Remedial Measure (IRM) and permanent remedy. In New Jersey, our LSRPs are reviewing historic site information and performing PFAS investigations as required by NJDEP. We are also acting as testifying experts on a case involving 1,4-Dioxane contamination in groundwater as a result of its use as a stabilizer in 1,1,1-trichloroethane, which was used as a solvent to degrease transformer parts.


For more information about our services or if you’re in need of a consultant for a site involving these contaminants, please contact us.