A contaminated sludge pond in East Hillsborough could soon have homes and businesses surrounding it (2024)

From the edge of a raised mound overlooking an abandoned phosphate mine in east Hillsborough County, overgrown green vegetation can be seen quietly soaking up the hot sun.

The 3,000-acre former Sydney Phosphate Mine closed down in the late 1950s, but the county used it as an unlined dumping site for liquid waste, like oil, until 1981.

The sludge pond area has since been designated as a superfund site, which means the federal government monitors the groundwater for contamination. At least three contaminants have been found throughout the years that are known to be cancerous, including benzene and vinyl chloride.

The property is now split in two. Back in 2010, the owners made a deal with the county to create renewable energy there before any of it could be developed for commercial or industrial uses, but building houses there was out of the question.

Now, the owners are each asking the county for comprehensive plan amendments to allow for more freedom to develop: one wants to remove the renewable energy requirement for development, while the other wants to construct homes.

Jessica Meszaros

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WUSF

Dover resident George Niemann lives right across the street and has been watching for development proposals for over two decades.

“We want the county to take appropriate action and care for its citizens and watch out for our safety," Niemann said.

He goes door-to-door informing residents about this land as part of the Fix Hillsborough Neighborhood Coalition, which is against these proposed changes.

"Let's try and use the land-use, our plan, to keep things the way they should be. Don't change the plan," he said.

Dennis Carlton is in the agriculture business and owns about one-third of the property on the east side called Turkey Creek Preserve.

He's got cattle on there and wants most of his property to remain the same, but he’s asking the county to allow warehouses and other types of industrial buildings on about 4% of the land … and he’s asking to do that before the renewable energy requirement.

"The energy component has never been done because the economics never have allowed it,” Carlton said.

He said his proposal will generate money to pay for the renewable energy requirement.

The remaining two-thirds of the former phosphate site is owned by University Energy Park.

It wants the county to allow construction of homes on the property — up to 1,900 homes on 500 acres.

Jacob Cremer, an attorney representing the company, said it’s already allowed to build commercial there, but said there’s also a need for homes in the area.

And they want to build a sustainable residential community that would partially fulfill the renewable energy requirement.

"If you look at the numbers in Florida, and especially in Tampa Bay with the inflation of housing costs ... we're going to need somewhere for the people who work there to live," Cremer said.

And he added that the community they’re proposing is further away from the superfund site than other homes already existing in the area.

Jessica Meszaros

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WUSF

The two property owners held community town halls to hear from residents this past year, but some locals still had concerns, so they called upon geological engineer Brent Jones to take a closer look.

"I decided to jump in and help the community and at least educate them on these environmental issues to be aware of," Jones said.

He's the brother of a resident who lives near the former mine and an environmental consultant based in Washington state who's been cleaning up hazardous waste sites around the globe for 35 years.

Jones clicked through publicly available government documents online and was quickly able to find a concerning contaminant that was exceeding allowable federal standards: 1,4-Dioxane.

"It's a dispersant that's put in oils … which is common at waste oil disposal pits," Jones said.

Basically, it's a cancerous chemical that spreads fast out and down when it comes into contact with groundwater. It’s also fairly new on the radar of environmental officials.

The federal government said on its website that this contaminant doesn't pose a risk to human health because the groundwater there is not being directly accessed by the public, but Jones cautions that moving around the soil for any development can cause the 1,4-Dioxane to spread further.

"You want to be very careful on building out large projects like this because they have a daisy chain of affecting downstream receptors," Jones said.

And neighbors of the former mine, like George Niemann, want groundwater testing for 1,4-Dioxane to take place throughout the 3,000 acres instead of just within the 56-acre superfund area.

"That stuff makes its way eventually into the water supply. And we don't know what the impact is. It's not clear because it's too new," Niemann said.

He and other residents would also like to know more about the ecological ramifications of developing on this land … how it would impact the animals and plants there.

Hillsborough County plans to hold public hearings on these proposals starting next month through the end of the year.

The county’s planning commission is holding a hearing for Dennis Carlton’s request to build before meeting the renewable energy requirement (HC/CPA 23-15) on Aug. 12, and then this issue will come before the full board of county commissioners tentatively on Sept. 26.

A planning commission hearing for University Energy Park’s residential proposal (HC/CPA 24-06) will take place Oct. 14, followed by a board of commissioners hearing Dec. 12.