Nine United States senators have urged financial regulators to crack down on prediction markets’ rise, specifically the ability to bet on wildfires.

The senators recently sent a letter to Commodity Futures Trading Commission Chairman Michael Selig, arguing he needs to “lead the charge” in regulating prediction markets, where people can place money on the outcome of future events. The letter comes after multiple state and local fire officials spoke with the senators, warning that offering such bets would encourage arson to make bets successful.

Polymarket, one of the most popular prediction markets, accepted over $1.2 million in bets related to the Palisades and Eaton fires in California. Another prediction market, called “Wyldfyre,” launched exclusively to accept bets on wildfires in California with the slogan “You can’t predict fire, but you can trade on it.”

The senators warn of the heightened risk that: “…individuals could be tempted to commit arson in order to make sure their bets are successful.”

“By offering contracts on fires, prediction market sites run the risk of encouraging people to influence fires that have already started, creating additional concerns around public safety and insider trading,” the senators’ letter said. “As the United States faces yet another record-breaking fire season this year, the Commodity Futures Trading Commission (CFTC) cannot allow these prediction markets to offer unrestricted betting on wildfires.”

The nine Democratic senators, including Oregon Senators Jeff Merkley and Ron Wyden, California Senators Alex Padilla and Adam Schiff, Minnesota Sen. Amy Klobuchar, Nevada Sen. Jacky Rosen, Nevada Sen. Catherine Cortez Masto, New Mexico Sen. Martin Heinrich, and New Hampshire Sen. Jeanne Shaheen, requested Selig answer the following questions by Aug. 14:

• Is the CFTC considering prohibiting (Designated Contract Markets) from offering event contracts on wildfires as
  part of the rulemaking process currently underway, given they are against the public’s
  interest?
• Does the CFTC have any plans to curb bets on wildfires on prediction markets in the
  United States? Does the agency have plans to address these contracts being offered on
  offshore markets?
• Does the CFTC believe event contracts offered on the following wildfire-related events
  are in the public interest:
  • How long would a wildfire last?
  • How much would a wildfire destroy?
  • How much would a wildfire grow by?
• Does the Commission have guidance or planned enforcement related to these wildfire
  event contracts?

Click here to read the full letter.