California State University workers are holding a one-day strike Tuesday to protest what they describe as unfairly low pay.

The workers’ union, Teamsters Local 2010, is in contract talks with the system after their contract expired at the end of June, according to the Los Angeles Daily News. The two sides failed to reach a deal on Oct. 31, according to the Long Beach Post.

Employees like plumbers, locksmiths and other skilled laborers say they’re underpaid compared with those who do the same work on University of California campuses.

The Teamsters claim “CSU pay lags behind that of comparable UC workers by an average of 23.6% when comparing UC and CSU campuses in the same county,” the Daily News reports.

The one-day strike on Tuesday is a “prelude … of what’s to come” if a deal isn’t reached, as the CSU faculty is also threatening to strike, maintenance mechanic Dennis Sotomayor told KTLA’s Ellina Abovian.

CSU provided KTLA with a statement in response to the strike.

“We have been informed that local Teamsters 2010 whose members serve as plumbers, electricians and other skilled trades workers, have announced a one-day strike on  November 14 at campuses within the California State University,” the statement said. “The CSU and the Teamsters have been unable to reach an agreement through the collective bargaining process.

“All CSU universities remain open and have contingency plans in place to maintain full university operations with as minimal disruption as possible for students, faculty, staff and visitors to our campuses. 

“The CSU remains committed to the collective bargaining process and reaching a negotiated agreement with the Teamsters as we have done with five of our other employee unions in recent weeks.”