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What is 1,4-dioxane? Seminole leaders discuss chemical in drinking water causing concern

Traces of likely carcinogen found in Seminole County, Sanford, Lake Mary

Faucet sink (FILE)

SEMINOLE COUNTY, Fla. – Seminole County leaders recently addressed concerns from residents about a harmful compound that’s been found in drinking water throughout the area, according to reports.

A report from the Orlando Sentinel shed light on the presence of the contaminating chemical, 1,4-dioxane, which has been found in water across Seminole County, Lake Mary and Sanford for years.

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Leaders allayed concerns about the contaminant, saying the water is safe to drink, no alternative source is necessary and boil water advisories have not been issued.

But what is 1,4-dioxane and why is it harmful?

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According to the Environmental Protection Agency and the Florida Department of Health, 1,4-dioxane is a manufactured chemical that easily dissolves in water. It typically presents as a colorless, flammable liquid and is a likely human carcinogen, or cancer-causing substance.

The chemical is often used as a stabilizer for solvents and cleaners and presents in paint strippers, dyes, greases, antifreeze and aircraft deicing fluids, the Seminole County website shows. But people can come in contact with 1,4-dioxane by drinking contaminated water or breathing in the chemical after it’s been released in the air while showering, bathing or doing laundry.

Health advisory levels for 1,4-dioxane are set at 0.35 parts per billion in groundwater, surface water and soil and are regulated by the Florida Department of Environmental Protection.

Levels of 1,4-dioxane at Seminole County’s Markham Regional Water Treatment Plant have averaged 0.18 parts per billion, roughly half of the EPA’s health advisory, officials said.

Previously, the contaminant had been traced to the former Siemens manufacturing site on Rinehart Road, which closed in the early 2000s, years before it was first found in the water during sampling mandated by the EPA in 2013.

“Our water has consistently been below the .035 ppb,” Environmental Services Director Kim Ornberg said at a Board of County Commissioners meeting Tuesday.

Ornberg also noted that her staff is committed to making sure the water is as safe as possible.

Seminole County’s potable water systems are sampled and tested for contaminants based on monitoring requirements established by the Florida Department of Environmental Protection. In recent months, the county has expanded sampling for 1,4-dioxane monthly to better understand its impact on the systems.

Concerns from the community have caught the attention of high-profile attorneys Mike Morgan and Mark Nejame, who both attended Tuesday’s meeting.

“It’s the water I drink. It’s the water my kids drink,” Morgan said. “But, I agree that this is not a level, at least at this point, for panic. It is a level for action.”

You can see what’s in your water by looking at the annual reports posted online.

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