NORTH WHITTIER >> More than 200 employees of the Los Angeles Sanitation Districts demonstrating against proposed pay cuts to fund pensions marched in front of the waste treatment agency’s headquarters Tuesday chanting slogans and carrying signs.

Employees from the districts’ wastewater plants located in Valencia and Carson joined engineers, supervisors and IT personnel in a brief rally outside the building on Workman Mill Road near the 60 Freeway, a first for the government agency usually not known for labor unrest.

The districts serves 5.6 million people in 78 cities and unincorporated areas, except for Los Angeles, which operates its own wastewater treatment plants and sanitary landfills. The county Sanitation Districts operates two working landfills, in Calabasas and Scholl Canyon near Glendale, several recycling plants and three refuse-to-energy plants, handling one-fourth the garbage of the county.

Much of the county’s sewage waste is funneled through the districts’ 1,400 miles of sewers and 11 wastewater treatment plants.

Mo Bina, a civil engineer and spokesman for the professional employees, said the demonstration did not interfere with the work of the employees and did not affect operations of districts sewage plants, landfills and recycling centers.

At issue is employee contributions to CalPERS, the state pension system.

Since 1982, the employees agreed to forgo a major pay increase as long as the districts paid for their 7 percent contribution. But now the districts want the employees to pay into CalPERS gradually through a one-half percent reduction in salary every year, Bina said.

The employees feel they’ve already paid for their pension contributions by not taking a pay raise, with the exception of small cost-of-living adjustments. The pension issue has roiled labor negotiations with other employee groups for the past two years, spilling over into the street on Tuesday.

“We love our jobs,” said Bina. “We just don’t think this is fair.”

Ramon Cortez, a human resources manager, said the districts continue to negotiate with individual labor units. He would not get specific, but said “some project pension costs are increasing.”

Districts General Manager and Chief Engineer Grace Hyde did not comment, referring all calls to Cortez.

In 2015, employees began hearing about the proposal to require them to pay pension costs that they feel they’ve already paid, Bina said.

Although the one-half percent cut in pay may not sound like much, it can add up if continued over many years and also would result in lowered pension payouts, he said.

“Management has given us no indication when that would end,” said Bina. “It seems like it could go all the way to 7 percent.”

Employees poured out of the headquarters at 11 a.m. during their break time, meeting up with others from the Service Employees International Union’s blue collar group who drove from outlying work sites on their own time. The joining of the SEIU employees, about 650 strong, with 500 of the professional employees unionized with the American Federation of State, County and Municipal Employees or AFSCME in February, represents a new kind of worker solidarity never before seen at the waste agency.

The issue of pension costs and salary reductions caused the headquarters workers to unionize, he said. The joint rally was the next step.

“I’ve been in the districts for 18 years and this is the first time this has ever happened,” Bina said. The last union activity took place in the 1970s, he said.

Bina said the districts’ budget is not in the red. He said the districts are poised to cover more than 80 percent of pension costs for future retirees.

“There is no financial need for this,” Bina said. “A lot of people feel this is political in nature.”