A federal lawsuit was filed against the Arizona Board of Regents alleging the University of Arizona underpays female professors in the College of Science.

A $20 million class-action lawsuit has been filed by a UA chemistry professor against the Arizona Board of Regents, alleging a pattern of sex discrimination that she said resulted in her being paid less than male colleagues at the school’s College of Science.

The complaint alleges that compared to men, the University of Arizona underpays female faculty by tens of thousands of dollars per year, does not adequately promote women and denies equal access to work resources. It also claims the school retaliates against women who complain about discrimination.

The federal lawsuit was filed on behalf of Katrina Miranda, UA associate professor in chemistry and biochemistry, who joined the school in 2002, and all other female faculty members within the College of Science who have been with the school for at least three years, said Andrew Melzer, one of the attorneys representing Miranda.

University spokesman Chris Sigurdson said the school is not commenting on the lawsuit.

It was filed by the national civil-rights law firm Sanford Heisler Sharp, which is the same firm that filed the $2 million gender-based pay discrimination lawsuit against the regents in January on behalf of Patricia MacCorquodale, a former Honors College dean at the UA. Two additional female UA deans have joined that suit.

Thursday’s filing was brought under the federal Equal Pay Act, which makes wage disparity based on sex illegal, and Title VII of the Civil Rights Act of 1964, which more broadly prohibits discrimination.

In terms of pay, the lawsuit alleges the university has denied Miranda and other women significant raises since at least 2011, while providing raises of tens of thousands of dollars to men in the same department with similar lengths of service.

In 2011, Miranda made $91,500; her salary for the 2017-18 school year was $99,714.

“These are small cost-of-living adjustments,” Melzer said. “What she’s being denied are substantial raises that men are getting.”

The suit states the UA paid a male professor of chemistry $130,500 for the 2016-2017 and 2017-2018 academic years — $30,000 more than Miranda, even though he was hired and received tenure at the same time as she.

“Through publicly available salary information, Dr. Miranda learned she has been underpaid by $9,000 to $36,000 per year from 2016 to 2018 alone compared to her male colleagues who have similar or lesser seniority and performance,” the lawsuit states.

She has held leadership positions — she served as assistant chair in the department — and published more than some male colleagues who have worked at the university for a similar amount of time yet have gotten the significant raises she had been asking for, according to the suit.

“When you’re making about $30,000 less than a man of similar qualifications and experience, you’re taking a hit. That affects people’s lives,” Melzer said.

Miranda was denied promotion to full professor in 2016 by College of Science Dean Joaquin Ruiz and former Provost Andrew Comrie despite recommendations from the department head, the lawsuit states.

Additionally, while about half of the associate professors are female within her department, only one out of eight of those holding full professorship status are women, according to the suit.

Resources are also not offered equitably to female faculty, the suit claims.

“For example, female professors routinely receive fewer research assistants and lesser mentoring opportunities than their male counterparts,” according to the suit.

When Miranda complained about the perceived discrimination, she claims the school retaliated last month by reducing her lab space, which is needed to do her work, by about 25 percent, Melzer said, although he said he didn’t know the reason cited for the reduction.

Lastly, the complaint accuses the university of not only perpetuating these practices, but of doing so knowingly while failing to correct its discriminatory practices.

“There is heightened attention to the area of gender inequality in all sorts of institutions,” Melzer said. “We hope these (suits) will achieve results for a more equitable society.”

Contact Mikayla Mace at mmace@tucson.com or 573-4158. Follow on Facebook and Twitter.