There are just over 5,000 people in Rye, New Hampshire. So when Mindi Messmer heard that four of them — all children — had developed an exceedingly rare cancer, she knew something was gravely wrong. Messmer, who had worked as an environmental consultant for 30 years, called Tom Sherman, who was her representative in the state legislature, to discuss what she feared was an environmental crisis.

The call was a first step in bringing the cancers — and, along with them, Messmer — into the public eye. That was in 2014. Within two years, the state Department of Health and Human Services acknowledged that the children’s illnesses constituted a rare official cancer cluster. Maggie Hassan, who was then governor of New Hampshire, set up a task force to investigate what became known as the Seacoast cluster and asked Messmer to join it. And in May 2016, less than a week before the filing deadline, Sherman, who had decided to run for state Senate, suggested that Messmer run for his seat in the state legislature.

“I said, ‘What are you crazy?’” remembers Messmer, who was in graduate school and running her own consulting business at the time. But after a week spent mulling both the cancers and a number of worrying pollution hotspots in the district, including a landfill that has been designated a Superfund site, several manufacturing sites, and a military base contaminated with firefighting foam, she decided to run.

Though she was a Democrat running in a heavily Republican district, Messmer won the seat in large part by focusing on water pollution and cancer. In her first year in the state legislature, three of her bills — all related to the environment and health — passed with bipartisan support. Messmer also fought to lower the state’s water standards for PFOA and PFOS, two chemicals in a class known as PFAS, which have been linked to cancer and other diseases. Both PFOA and PFOS have been found at the contaminated sites in her district.

Now Messmer is hoping to bring her focus on the need for clean drinking water to Washington. And while her environmentally inspired campaign to represent New Hampshire’s 1st District may seem anomalous, she’s not the only one who’s hoping to win a seat in Congress by tapping into the wave of bipartisan outrage about health and water pollution. She’s not even the only midterm candidate who’s focusing on PFAS chemicals.