The Florida Everglades has become the latest region to react against oil drillers and fracking, a technique that has spurred worries about earthquakes and water contamination across the country.

Concerns about an “enhanced extraction procedure” that conservationists in South Florida likened to fracking led an oil drilling firm to be slapped with a cease-and-desist order, face scrutiny from a U.S. senator and be questioned by residents about water supply safety. The company, however, contends that it is not using hydraulic fracturing, commonly known as fracking.

Dan A. Hughes Co. sought a permit in December to try a new technique on its 4-month-old oil well on a tomato farm in Collier County’s portion of Big Cypress National Preserve. But the state rejected the application, saying it lacked sufficient information to be sure that groundwater would be protected.

The procedure, which had begun legally, continued for a day in defiance of the state’s cease-and-desist order, the Department of Environmental Protection said last month. The state reached a $25,000 settlement with Dan A. Hughes and ordered the company to hire consultants to check whether the advanced technique would affect aquifers. The consultant’s report is due in December.

[Updated, 2:30 p.m. PDT May 2:  On Friday, the state banned the company from beginning to drill the five other wells for which permits had been secured until the review is complete. Normal procedures on the disputed well may continue, an agency spokeswoman told the Los Angeles Times. In a statement, the company said it would cooperate.

“We are confident the results will show that our operations are safe, and that the ground water was not impacted by our operations,” the statement said.]

On Thursday, U.S. Sen. Bill Nelson (D-Fla.) said the U.S. Environmental Protection Agency should scrutinize Dan A. Hughes’ application to drill a waste storage well next to the oil well.

“We cannot tolerate expanded industrial drilling activities that pose a threat to the drinking and surface water so close to the Florida Everglades,” Nelson said in his letter.  “The recent discovery of a fracking-like incident there raises serious concerns about whether outside wildcatters would soil one of the world’s great environmental treasures.”

Dan A. Hughes contended in a statement Thursday that what it had done in December was an acid stimulation, commonly known as acidizing — not fracking.

The company said acid stimulation, which involves injecting hydrochloric or hydrofluoric acids to dissolve oil-bearing rock, has been done for 50 years in Florida, including by authorities constructing water wells.

Dan A. Hughes noted that it had completed a similar procedure last summer. But this time around, workers also injected what it described as a “modest volume” of water and sand “under enough pressure to prevent the formation from closing in on itself.” The exact mix is considered a trade secret.

In hydraulic fracturing, a mixture of mostly water and sand is blasted into rocks to free oil and natural gas.

“Our well completion process prevents any fluids from contacting underground water by sealing the well off from the reservoir with multiple layers of steel and concrete,” company spokesman David Blackmon said in a statement.

More than three dozen exploratory drilling permits have been issued in the past few years in Florida as speculators bet that the earth there holds valuable fuels.

Some residents and officials in Collier County have expressed frustration about the state issuing the permits for sites within delicate swamplands and just miles away from a panther refuge. Last month, the Collier County Commission called on the state to revoke Dan A. Hughes’ permit for the tomato farm well.

The EPA doesn’t have control over exploratory oil wells, but it does issue permits for underground storage of waste generated from fracking and drilling. The agency is in the midst of reviewing public comments about whether to let Dan A. Hughes open a waste well about 1,500 feet from homes in Golden Gate Estates.