CHICAGO (CBS) — Nonunion security guards at DePaul University were staging a one-day strike on Tuesday, claiming they are not paid a living wage.

The guards work for Guardian Security Services, and staff the front desks at DePaul residence halls.

The security guards have said the company pays so little that employees often struggle to pay for basic needs, such as groceries and CTA passes. They also said the low wages have led to such a high turnover rate that many buildings have been left unprotected due to staffing shortages.

In protest of those conditions, the guards were planning a one-day strike on Tuesday. Service Employees International Union was helping organize the walkout.

University officials said they are working with Guardian to address any expected staffing shortages due to the protest.