Eight U.S. senators, including four presidential contenders, called on McDonald’s to do more to combat workplace harassment, saying the number of misconduct reports is “unacceptable.”

In a letter dated Tuesday, the lawmakers urged chief executive Steve Easterbrook to require all McDonald’s franchise stores to update their policies against harassment, abuse and employee retaliation. They also wanted to know how the fast-food giant would evaluate workplaces to address harassment complaints and investigate reports of unsafe working conditions.

The letter follows a coordinated effort by more than two dozen current and former McDonald’s workers who filed sexual harassment complaints last month with the U.S. Equal Employment Opportunity Commission and in court. The allegations include groping, indecent exposure, propositions for sex and lewd comments, and the incidents reportedly took place at corporate and franchise stores in 20 cities.

The filings against McDonald’s were part of a broader, years-long push to hold the company accountable for what workers say are inadequate responses to complaints of abuse. They also come as the #MeToo movement reaches beyond Hollywood and the entertainment industry.

The letter was signed by Sens. Chris Van Hollen (D-Md.), Tammy Duckworth (D-Ill.), Richard Blumenthal (D-Conn.), Sherrod Brown (D-Ohio), and White House hopefuls Sens. Kamala D. Harris (D-Calif.), Amy Klobuchar (D-Minn.), Elizabeth Warren (D-Mass.), and Bernie Sanders (I-Vt.).

McDonald’s said in a statement that it “has always had an unyielding commitment to providing a safe and respectful work environment for all. Both the company and our Owner Operators understand that we must provide a positive experience in the restaurant and create an environment where everyone feels respected and valued.”

The chain also referred The Washington Post to a statement from Joe Jasper of the National Franchise Leadership Alliance, an elected body that represents franchisees.

“There are serious and important conversations continuing all across our country to safeguard the rights of individuals. As owners of small businesses in almost every community, we spend our days in our restaurants and see our team’s as an extension of our family. No level of harassment has a place inside a McDonald’s,” Jasper said. “We take seriously our responsibility to ensure that individuals who report harassment or retaliation are heard and protected.”

McDonald’s said it has updated its policy to better inform employees of their rights and has provided training to most restaurant owners and general managers, among other initiatives.

But in the letter Tuesday, the senators wrote that “we remain troubled that the procedures, policies and activities outlined fall short of providing a safe and respectful work environment for all workers who wear the McDonald’s uniform.” Senators took particular issue with the policy changes not being required for franchisees, which make up the vast majority of McDonald’s stores. Of the restaurant’s 14,000 locations in the United States, about 1,000 are corporate-owned, while franchisees operate the rest.

“[It] is imperative that the McDonald’s Corporation require all franchise locations to adopt the updated policies to guarantee that all workers will be covered by the new protections and support services,” the senators wrote.

Altogether, McDonald’s employs about 850,000 people in the United States and is the world’s second-largest private employer.