In a bipartisan effort to address farmers’ economic woes, Senate Majority Leader John Thune (R-South Dakota) and Senator Amy Klobuchar (D-Minnesota) introduced a bill Thursday that would provide farmers with more detailed information on fertilizer pricing, while Klobuchar also joined with Senator Roger Marshall (R-Kansas) to introduce a bill to expand domestic fertilizer production.

Senator Josh Hawley (R-Missouri) sent a letter to the five largest fertilizer companies asking them to answer detailed questions related to price gouging and asked the Department of Justice (DOJ) to start a formal investigation into their practices.

That letter followed a Bloomberg report earlier this month, in which unnamed sources claimed the DOJ is already probing whether companies have colluded to raise fertilizer prices. In response to a Civil Eats inquiry asking for confirmation of that investigation, a DOJ spokesperson said in an email that the agency could not comment on the status of a pending criminal investigation.

“The Department of Justice stands ready to investigate and prosecute any company that exploits opportunities by engaging in collusive schemes that artificially increase prices and harm American consumers, farmers, and businesses,” they said.

The activity in D.C. comes amid increased concerns from farmers and farm groups over rising operating costs.

On Thursday, more than 50 of the country’s largest farm groups sent a letter to President Donald Trump asking for additional economic assistance for farmers. Recent spikes in fertilizer and fuel prices due to the closure of the Strait of Hormuz are “further straining a farm economy that already had its back against the wall,” they said.