Security officers who patrol many city-owned buildings and much of Baltimore’s Harbor East neighborhood will be absent Thursday as the guards participate in a one-day strike.

Guards with Abacus Corp., Metropolitan Protective Services and Urban Development Solutions will participate in the strike, organized by Service Employees International Union’s Local 32BJ, in protest of efforts they say have barred Abacus employees from unionizing.

Baltimore contracts with the three companies for armed and unarmed security services at city-owned and leased properties. City facilities staffed by private security include public-facing office buildings like the Abel Wolman and Benton buildings adjacent to City Hall, but the officers are also responsible for the city’s wastewater treatment plants, impound lots, health clinics, animal shelters and even some police stations.

Abacus officers also protect 10 commercial buildings in Harbor East and provide roving patrols, said Julie Karant, a spokesperson for Local 32BJ.

About 200 employees of Abacus will participate in the strike, Karant said. Metropolitan Protective Services and Urban Development Solutions have an additional 120 employees in Baltimore, but not all will participate.

Baltimore City Council members Odette Ramos and Jermaine Jones are expected to participate in a strike rally.

Earlier this year, the City Council approved legislation requiring private security companies to pay their officers wages and benefits equivalent to those of federal contract officers.

Federal contract officers are paid an hourly rate of $18.29, with a $5.55 hourly supplement for health care. The average city security guard is paid $15.80 per hour, City Council members said at the time. The wage increase, which was approved by Mayor Brandon Scott, will not be effective until 2027.

Union officials said the company has blocked Abacus guards from unionizing. They have filed several unfair labor practice charges against the company alleging that workers were discriminated against and fired for their participation in union activities.

Michael Brady, chief administrative officer for Abacus, said the company denies any unlawful activity and has cooperated fully with regulators in regard to the unfair labor charges.

Brady said its Baltimore security officers are paid $25 per hour and that the company voluntarily increased wages ahead of the wage legislation becoming effective. Company officials have said there are contingency plans should there be unexpected call-outs Thursday.

“Abacus will not allow the union to disrupt the service and safety provided to Baltimore City,” Brady said.