The Suffolk County Water Authority on Monday proposed installing more treatment systems to remove the chemical 1,4-dioxane from drinking water, with potential capital costs of at least $75 million, officials said.

SCWA officials told Suffolk County legislators they were planning to install 31 new advanced treatment systems at sites where levels of the likely carcinogen are higher than a proposed state limit.

The authority's projected time frame of six years to remove the chemical is the longest yet put forward by a Long Island water provider. Environmentalists say six years is too long to wait.

SCWA officials said they will seek funding through state grants, and likely will have to seek a rate increase specific to treating 1,4 dioxane and perfluorinated compounds used in products including firefighting foam and Teflon. Officials are still working to determine the amount, but customers could pay an extra $100 per year.

The SCWA plan depends on water quality standards the state Department of Health ultimately sets.

The projected capital costs depend in part on how many sites require treatment systems.

If officials have to install treatment systems at every site where the contaminant has been detected — about 262 public wells, including some no longer in service — it would cost at least $600 million for installation, plus annual operating costs of about $12 million a year, officials said.

“There’s a lot of things up in the air, regrettably,” SCWA chief executive Jeffrey Szabo said in an interview.

The chemical 1,4-dioxane is designated by the U.S. Environmental Protection Agency as a likely human carcinogen associated with liver and kidney damage. It has been found widely on Long Island, and is not removed through conventional treatment methods, water providers said.

The man-made chemical is found in industrial solvents and in trace amounts in cosmetics, detergents, shampoos and other home care products.

The state health department could become the first in the nation to set a limit on the chemical — at a proposed 1 part per billion — and is planning to offer $350 million in grants for treatment. But a final decision on the limit could be months away.

A coalition of environmental groups and lawmakers in Albany on Monday called for the state to adopt stricter standards for emerging contaminants 1,4-dioxane and the perfluorinated compounds PFOS and PFOA. The groups say the state's proposed levels are not protective enough of human health.

Long Island water providers said earlier this year that adding treatment systems to 185 drinking wells contaminated by the 1,4-dioxane in Suffolk and Nassau would cost $840 million, according to an estimate by the Long Island Water Conference.

In Suffolk, 75 of about 600 public drinking water wells in service have had 1,4-dioxane levels higher than 0.5 parts per billion, officials said. A plan to install systems at all those wells would cost about $130 million.

New Advanced Oxidation Process treatment systems each cost between $1.5 million and $6 million to install, officials said.

They said they are also open to using other technology, but the Advanced Oxidation Process is the only system approved in the state so far. 

Water providers have suggested it would take years to meet a new standard for 1,4-dioxane, because it's so expensive to treat, the technology has to be tested at individual sites and is made by a limited number of manufacturers.

Environmental advocates said the state should enforce new standards as quickly as possible.

"Six years is too long for the public to wait for safe, clean drinking water. We have already been drinking this toxic [chemical] for decades," said Adrienne Esposito, executive director of Farmingdale-based nonprofit Citizens Campaign for the Environment.

Szabo said it took two years to get approval for a system in Central Islip, and two others still are under development for pumps in Huntington and East Farmingdale. Officials estimated they could install six systems per year. The majority would be in northwest Suffolk.

“We’re moving forward as fast as we can possibly go,” Szabo said.

The state Department of Health said Monday that if water systems were to exceed standards, they would have up to 30 days to notify customers.

“The Department will review all proposed compliance time schedules and we look forward to working with water systems and municipalities to ensure compliance can be achieved,” spokeswoman Erin Silk said in a statement.

Most Long Island water providers said they need multiple years to implement treatment for 1,4-dioxane, said Dennis Kelleher, public relations chairman for the Long Island Water Conference and a vice president at H2M architects + engineers.

“We need much more time to do proper, design, planning and construction of treatment systems,” Kelleher said. “A lot of them are going crazy to get as much treatment in place as possible.”

Under the proposed regulation, the new maximum contaminant level would be in effect in 60 days.

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