A fracking oil well in Colorado. Getty

Citing concerns that fracking in their county could ruin the water supply, officials in Miami-Dade County, Florida, have formally proposed banning the natural gas extraction method outright.

A county commission will debate the measure Tuesday during a public meeting. The potential ban comes just months after the state Senate failed to pass legislation that would have prohibited local governments from regulating fracking on their own.

“This is about our water supply,” Daniella Levine Cava, a commissioner and the sponsor of the ordinance, told the Miami New Times. “In this kind of acid fracking, the chemicals are potentially very dangerous and not disclosed. The risk of them entering into our water supply through our porous limestone substrate is too high.”

Fracking is particularly controversial in Miami-Dade County because the whole place sits on top of the Biscayne Aquifer, which supplies water to a large number of Floridians. If that water supply were polluted by any source, scientists have said, then it is likely that the aquifer would remain polluted forever. Fracking in the county would require penetrating that aquifer. If something went wrong — the chemicals injected into the ground are “trade secrets” and undisclosed by the companies — then that water supply would be at risk.

Fracking became formally legal in Florida earlier this year. Much of the state sits atop fragile aquifers and the state has a sponge-like geology so residents have been quick to voice concerns that the worst case scenario could lead to contaminated water sources. There are at least 57 communities in Florida that have passed resolutions banning the gas extraction method in their towns and cities.

Nationally, Ohio, Texas and Oklahoma are the only states to have made it illegal for local governments and communities to ban fracking.

The Environmental Protection Agency found last year that fracking doesn't pose a significant threat to drinking water — and has been criticized heavily for those findings. Those critiques have come even from members of the EPA's Science Advisory Board, which said in January that the prior EPA conclusions about the impact of fracking on drinking water were not supported by the data that they analyzed.