Oil spill workers collect tainted debris and dark oil patches along the beach as oil washes ashore on June 10, 2010 at Perdido Pass, Alabama. (Photo: Cheryl Casey / Shutterstock.com)

The public still doesn’t know the extent of fracking in the Gulf of Mexico, and as the fifth anniversary of the disastrous BP oil spill quickly approaches, environmentalists are demanding answers from the federal regulators who have been keeping them in the dark.

It’s been several months since Truthout and the Center for Biological Diversity filed separate requests for federal records on fracking in the Gulf, but the agencies tasked with overseeing offshore oil and gas production have yet to hand over any documents.

“It seems like offshore fracking activities have been kept secret, and it makes one wonder what the agencies are trying to hide; perhaps it is just their own failure to adequately regulate the oil industry,” said Miyoko Sakashita, an attorney for the Center.

In 2014, news reports indicated that oil companies are bringing the sort of large-scale fracking technology that has ignited a national controversy onshore to deepwater drilling platforms in the Gulf. Unlike onshore fracking, data on offshore fracking is not publicly available on databases kept by the government and industry trackers like FracFocus.org.

In response to requests from journalists, federal regulators have released limited data about 115 oil and gas wells in the Gulf, where a more established offshore fracking technique known as “frack packing” was used to complete or enhance oil and gas production during 2013.

Offshore fracking involves forcing water mixed with chemicals and sand deep under the seafloor to break up rock and release oil or natural gas. Frack-packs are typically smaller than high-volume, horizontal fracking operations and are often used to enhance or complete production in existing wells.

In a statement to Al Jazeera, the Bureau of Safety and Environmental Enforcement (BSEE), which permits and inspects offshore oil and gas production for the US Department of the Interior, acknowledged that the data it provided to reporters is incomplete and does not include any information on fracking techniques “involving higher fluid volumes and extending longer distances.” The agency said such techniques have been “minimally used in the Gulf,” suggesting that a small but unknown number of advanced, large-scale operations have occurred there.

“In the last couple of years, the Obama administration has leased tens of millions of acres in the Gulf of Mexico for exploration and extraction purposes, and we are starting to understand that fracking is a technique that the industry likes and is using,” said Jonathan Henderson, an environmental watchdog with the Gulf Restoration Network. “As more and more areas of the Gulf become open, it’s going to be in deeper and more dangerous territory.”

In October 2014, the Center for Biological Diversity requested, under the Freedom of Information Act (FOIA), a wide range of records related to any fracking operations that have occurred in the Gulf over the past 25 years, including the government’s environmental assessments of the practice, if any exist. The request is filed with BSEE and its sister agency, the Bureau of Ocean Energy Management (BOEM).

In January, the Center filed a lawsuit against both agencies for failing to issue a timely response to the group’s FOIA request. In response, BOEM and BSEE requested additional time to compile records, noting that permit modification forms do not have “designated fields” to indicate that they involve fracking, so over 3 millions pages of documents would have to be reviewed by hand.

Sakashita said the Center is currently trying to work out an agreement with the agencies and could not comment on the specifics of the deal.

Truthout filed a much narrower request with BSEE in November, asking for copies of permits that have approved fracking in the Gulf since January 2012, along with any permit applications that are currently under review.

Sakashita noted that it should not take federal agencies months to dig up records on the activities they are supposed to regulate, especially basic documents like permits.

“The thing that I find shocking is that, this is the agency that’s supposed to be regulating offshore drilling, and they don’t keep track of it nor have a system that is amenable to searching for it,” Sakashita said.

A BSEE spokeswoman said she could not comment due to ongoing litigation.

A key concern among environmentalists like Sakashita and Henderson is the wastewater produced by offshore fracking. Large fracking operations can produce millions of gallons of wastewater tainted with toxic chemicals used in the fracking process, along with naturally occurring pollutants such as arsenic and lead.

In 2014, the Center analyzed industry data and found that 10 chemicals in fracking fluids used in frack-packing operations off the coast of California posed a threat to marine wildlife in the region.

The Environmental Protection Agency permits offshore platforms in the Gulf and other regions to dump wastewater overboard if the waste contains levels of certain pollutants that do not exceed federal standards. Wastewater containing certain pollutants, such as crude oil and diesel fuel, must be treated before being dumped overboard, but the permits do not cover the myriad chemicals often used in fracking.

Henderson, who has been monitoring pollution from oil and gas production in the Gulf since the massive 2010 BP oil spill, said that the public needs to know what is being dumped into the waters that many communities along the Gulf Coast depend on for economic survival.

“It’s very much an existential threat,” Henderson said. “Our very survivability depends on a healthy ocean, it depends on healthy wetlands, it depends on fisheries being productive, and not knowing what kind of chemicals are going into the ecosystems that we depend on, it’s really despicable that we would be subject to these kind of risks without knowing what the risks are or how to respond to a fracking disaster.”

Fracking has been linked to “serious problems” on land that researchers are only beginning to understand, Henderson said, so environmentalists and first responders need to know where and when fracking occurs offshore so they can be prepared to respond to any potential accidents.

“The seafloor of the Gulf of Mexico is not flat; it is full of canyons and ridges and steep inclines and declines; there’s faults; it’s unstable, and any activity that industry engages in on the seafloor, it can have effects that could be catastrophic,” said Henderson, who questioned whether the government has learned any lessons from the Deepwater Horizon disaster that caused the worst oil spill in US history.

Little was known about offshore fracking until 2013, when a series of investigative reports by Truthout revealed that frack-packing technology was being deployed from oil platforms in the Santa Barbara Channel.

The Center for Biological Diversity and the Environmental Defense Center in Santa Barbara recently filed separate lawsuits against BOEM and BSEE, alleging that the agencies illegally rubber-stamped permits for fracking in federal waters off the California coast. Both lawsuits seek to halt fracking in Pacific waters until the agencies come into legal compliance.