Union members are scheduled to vote Saturday on a new four-year contract that includes an annual average wage hike of 4 percent for about 2,200 janitors and office cleaners in Montgomery County and Baltimore.

A new agreement tentatively reached last Sunday might have averted a strike that could have meant dirty offices in more than 190 commercial buildings in the state, including the headquarters of media giant Discovery Communications in Silver Spring and the Rock Spring Office Park in North Bethesda. The list also includes the two tallest buildings in the state, the 40-story Legg Mason building and 37-story Bank of America building, both in Baltimore.

The Washington Service Contractors Association, which represents major commercial cleaning companies, and Service Employees International Union Local 32BJ ironed out the agreement, after workers threatened to strike if a new contract agreement was not reached by midnight Monday.

Peter Chatilovicz, a partner with the Washington, D.C., office of law firm Seyfarth Shaw and the chief negotiator for the cleaners association, called it a fair deal for all parties.

“There was a good give and take,” he said this week. “We are hopeful and optimistic that it will be ratified on Saturday.”

The agreement is “not just a win for working families and our communities, but it ensures tenants will receive professional service and gives our economy a much-needed boost,” Jaime Contreras, director of SEIU 32BJ’s Washington, D.C., area, said in a statement.

The sides’ last agreement in 2007 included a 7 percent annual pay increase.

The median hourly pay of building cleaners in Maryland was $11.33 in 2010, a 23 percent increase from 2006, according to estimates by the U.S. Department of Labor. The median pay for all occupations in the state of $19.11 rose by 14 percent in the same time.

Maryland’s average hourly pay for cleaners was lower than the national average in that category, which was $12.72, a 33 percent jump from 2006.

The contract also covered some 5,000 cleaners in Washington and 4,000 in Northern Virginia.

Ratification votes will take place Saturday in Silver Spring, Baltimore, Washington and Falls Church, Va.

kshay@gazette.net