President Donald Trump undid many of his predecessor’s environmental and energy accomplishments last year, and Democrats are hoping to galvanize some of the frustration over Trump’s efforts to flip the House.

Democrats need to turn at least 24 seats from red to blue to win the chamber. The Democratic Congressional Campaign Committee has identified 94 competitive districts, focusing in areas where Hillary Clinton won the vote in the 2016 general election.

Congressional battles in 2017 over health care and tax reform, as well as the national conversation on sexual misconduct, will likely be at the forefront of voters’ minds as they head to the polls for the primary and general elections.

Environment and energy could also play a role in certain vulnerable races. Trump last year withdrew from the Paris Accord on climate change, scrapped the Clean Power Plan to reduce carbon emissions from the electricity sector, and reduced the size of protected federal lands. Locally, Americans had to contend with their own environmental concerns, from wildfires in California to contaminated rivers in North Carolina.

Regional issues, such as the management of public lands, water quality, and adaptation to a changing climate could manifest into talking points in affected districts, Megan Mullin, an associate professor of environmental politics at Duke University’s Nicholas School of the Environment, told Bloomberg Environment.

“I would anticipate a lot of language on infrastructure” on the campaign trail, Mullin said. “It’s about building communities that are more resilient in the face of these risks.”

Mullin pointed to a recent event in which a local environmental problem caused an upset in the Trump administration’s plans. Wilmington, N.C.-area residents are struggling with contamination of the chemical known as GenX, from a nearby chemical plant, in their drinking water. That incident fueled the state’s two Republican senators to oppose a Trump nominee with a history of siding with the chemical industry for a high-level post at the Environmental Protection Agency.

Bloomberg Environment identified five House races with vulnerable incumbents in which environmental or energy issues could play a prominent role:

Texas’ 23rd District

Rep. Will Hurd’s (R) seat, which covers more than 800 miles along the U.S.-Mexico border in a predominantly Hispanic district, is one of four Texas districts targeted by the Democratic Congressional Campaign Committee.

The competing priorities of conservation and border security could clash in the race to win Texas’s 23rd congressional district, particularly in the debate over Trump’s border wall. The district is home to Big Bend National Park that abuts the Rio Grande, the international demarcation line. Hurd supported a 2015 bill that would remove hurdles to road construction in Big Bend to increase border security, a move his 2016 Democratic opponent Pete Gallego—who held the seat from 2013 to 2015—used to attack Hurd in his campaign.

The oil and gas industry is a big jobs generator in the district. Hurd has raised $1.34 million in political contributions since Sept. 29, 2017, according to Bloomberg Government. Energy companies have contributed about $61,000 to his campaign.

Hurd has outraised his closest Democratic competitor, former federal prosecutor Jay Hulings, by nearly seven times.

Florida’s 26th District

Rep. Carlos Curbelo (R) represents a rare breed within the GOP: a Republican who not only believes in the mainstream science on climate change, but is also dedicated to tackling the issue. The South Florida congressman and Trump critic is facing a challenging re-election in a district that voted for Hillary Clinton by 16 percentage points in 2016.

The district, which includes the Florida Keys, could be swayed by Curbelo’s credentials as the co-founder of the bipartisan Climate Solutions Caucus in the wake of last year’s Hurricane Irma and the threat of sea-level rise. But some environmentalists, such as the League of Conservation Voters’ Craig Auster, point out that the caucus hasn’t done much to propose actual solutions.

Curbelo has raised $1.75 million, according to Bloomberg Government. In 2016 he received a key endorsement from the ClearPath Action Fund, an organization that supports conservative approaches to low-carbon energy.

Ricky Junquera, a former press secretary for the Sierra Club and campaign staffer for Curbelo’s 2016 opponent, Joe Garcia, is one of the Democrats ready to challenge Curbelo. The Sierra Club has received funding from Bloomberg Philanthropies, the charitable organization founded by Michael Bloomberg, the ultimate owner of Bloomberg Environment.

California’s 49th District

Nine-term GOP Rep. Darrell Issa squeaked by in his last re-election race against Democrat Doug Applegate with a 1,621-vote lead in this coastal Southern California district. Residents of the 49th California Congressional District voted for Clinton in that same election, the first Democratic presidential candidate to win since Al Gore captured the district in 2000.

Issa, the former chairman of the House Oversight and Government Reform Committee, used his perch to investigate the Energy Department’s $535 million loan guarantee to Solyndra, a solar energy company that went bankrupt in 2011. Although he recently joined the bipartisan Climate Solutions Caucus, Issa has stuck to his party line opposing cap-and-trade schemes and in favor of the Keystone XL pipeline.

Issa’s district was seriously burned by wildfires last year, a point that could play into campaign trail discussions on climate change. One of his top Democratic challengers, Mike Levin, is an environmental attorney by training and has worked for several energy companies. Levin is the frontrunner among Democratic candidates for fundraising, amassing close to $1 million, according to Federal Election Commission filings.

Issa has raised only slightly more: $1.25 million, according to Bloomberg Government.

North Carolina’s 9th District

Rep. Robert Pittenger (R) safely won his re-election in 2016, getting 58 percent of the vote to his challenger’s 42 percent on the same day Trump won the district by 12 percentage points. This year, his victory is less certain.

Pittenger is facing a challenge from within his political party and from a well-funded Democrat with a renewable energy background.

Dan McCready, a Marine Corps veteran, co-founded an investment firm for utility-scale solar farms in 2013 that has raised $80 million for solar projects, according to a February 2017 Fortune magazine profile of the company.

McCready currently leads the pack in fundraising, collecting more than $875,000 to Pittenger’s $635,344 as of June 30, according to Federal Election Commission filings. McCready has more than double the cash on hand as Pittenger.

But before he faces a Democrat in November, Pittenger must win against evangelical pastor Mark Harris in the primary. Pittenger won the 2016 primary against Harris by just 134 votes, and former White House strategist Steve Bannon is planning to help Harris’s campaign, according to the McClatchy news service.

Maine’s 2nd District

To date, Republican Rep. Bruce Poliquin has burned through far more money than his opponents — he’s spent 22 times the amount that Democratic frontrunner, state House Rep. Jared Golden, has — but Democrats could soon catch up with the entry of a familiar name in the Maine conservation world.

Lucas St. Clair, son of the Burt’s Bees personal care company co-founder, announced his candidacy Oct. 2, the sixth Democrat to enter the race. St. Clair’s activism helped push President Obama to create the Katahdin Woods and Waters National Monument, a 87,500 acre-federal land designation. Republicans have criticized national monuments, saying they can prevent local communities from using the land for hunting, fishing, logging or other uses.

St. Clair’s campaign has yet to report contributions to the Federal Election Commission, but his family’s wealth could support his fledgling campaign. Elliotsville Plantation Inc., St. Clair’s family foundation to conserve Maine land, is worth an estimated $131 million, according to the Mainebiz news site.

St. Clair faces a tough primary against Golden, a former Marine and one of several military veterans national Democrats are trying to get elected to the House.

Poliquin has raised $1.59 million, according to Bloomberg Government.