A spokesman for the Baltimore County Fire Department said that police were called to a nail salon in the shopping center around 9:30 p.m. ET for a report of a former employee on the premises.
Police confirmed to Fox News Digital that the suspect set a fire that sparked the explosion just after police arrived at the scene.
Four police officers and two medics were taken to area hospitals with non-life threatening injures. The person believed to be the former employee suffered life-threatening injuries.
The explosion happened at the Libra Nails and Spa inside the Security Station Shopping Center in Windsor Mill. It is located about 12.5 miles outside Baltimore.
Baltimore County fire officials said the explosion may have involved hazardous materials.
Fire officials said the fire was under control around 10:30 p.m. ET.
Pictures show that the nail salon sustained heavy damage with all of its windows blown out.