Update: The statewide fracking ban bill was passed by the Maryland Senate on March 27 by a vote of 35 to 10. It now goes to the desk of Gov. Larry Hogan, who is expected to sign it.

Maryland is poised to become the third state to outlaw fracking, as the Senate prepares to vote on a statewide ban and with Gov. Larry Hogan saying he will sign it.

The permanent ban would go into effect before a moratorium on the drilling practice expires, meaning that fracking in the state would end before it ever began.

Late last week, Hogan, a Republican who has called fracking "an economic gold mine," announced his unexpected support for the ban.

"We must take the next step to move from virtually banning fracking to actually banning fracking," the governor said at a press conference last Friday. "The possible environmental risks of fracking simply outweigh any potential benefits."

It marked a stunning turnaround for a Republican governor, especially as the Trump administration has voiced unfettered support for the fossil fuel industry. Maryland's bill needs a full Senate vote to pass, but especially now that the governor has added his support, legislators and activists have said it seems likely that it will succeed.

"We're confident that we have the votes to pass the bill to ban fracking," said Thomas Meyer, a senior organizer with the nonprofit Food & Water Watch. "The members have expressed their support."

It's unclear when the vote will happen, but the legislative session ends on April 10. The bill was first introduced in the House, which approved it, 97-40, on March 10. In the Senate's Education, Health and Environment Committee Wednesday it was approved in a 8-3 vote.

If the bill passes, Maryland will join New York and Vermont as the only states that have banned the controversial drilling practice, although Vermont appears to have no natural gas resources, making its ban largely symbolic. Fracking is practiced in about 20 states.

"Obviously we're opposed to it," said Drew Cobbs, the executive director of the Maryland Petroleum Council. "Though probably more than anything else it's a symbolic gesture since it's only a small part of western Maryland that could be developed."

Two counties in western Maryland sit on top of the Marcellus Shale, the same bedrock formation that spawned oil and gas booms in the neighboring states of Pennsylvania and West Virginia.

In 2006, energy companies started to express interest in moving into Garrett and Allegany counties. According to the Maryland Geological Survey, landmen—energy company representatives who come into a community ahead of oil and gas development to make deals and pave the way for drilling—started showing up. More than 100,000 acres were leased by oil companies, Cobbs said, but over time those leases have expired.

In 2011, before prospectors had the chance to assess how much oil and gas could be in the state, then-Gov. Martin O'Malley called for a study of the economic and environmental impacts of drilling into shale. Drilling in Maryland was off limits until the study's completion in 2014.

In March 2015, state legislators passed a moratorium that would last until October 2017. The bill went into effect without newly-inaugurated Hogan's signature.

Meyer, who has spent the last two and a half years organizing grassroots support for a state fracking ban, said he couldn't believe it when he got word last week that the governor supported the ban.

"I was a little confused at first and then kind of started screaming," he said. "It was probably four or five minutes of pandemonium. This was not just a win—it was a truly shocking revelation."

Hogan hasn't said the reason for his change of heart, but Meyer said support for a ban has been growing. He said he hopes that Hogan's move sends a message to governors in other states—particularly Democrats like Jerry Brown in California and John Hickenlooper in Colorado, who are pro-environment in some aspects, but continue to support fracking—that the practice's risks outweigh its benefits.