The Office of the State Fire Marshal says a propane leak in the basement of the business in northern Carroll County was the origin and cause for an explosion that injured two female employees Thursday.
The incident occurred at about 2:15 p.m. in the 1200 block of Silver Run Valley Road, an area north of Westminster.
According to the fire marshal's office, Heather Bree Harbi, 38, was transported by state police helicopter to Johns Hopkins Bayview Burn Center with first- and second-degree burns to her upper body. She was in critical but stable condition as of Friday, officials said.
The second victim, Julie Ann Griffith, 39, was also transported via state police helicopter and was taken to the R. Adams Crowley Shock Trauma Center after receiving an injury related to the explosion. She was in good condition Friday and is expected to be released today, the fire marshal's office said.
The fire marshal's office said the 20-by-40-foot single story building was originally built in 1850 as a small schoolhouse. It has since been remodeled and operates as Premier Financial Solutions.
Officials said in a press release that investigators determined a propane leak occurred and pooled in the basement area, but the ignition source remains under investigation.
Nearly 50 firefighters and emergency medical personnel responded to the scene of the explosion and fire, officials said. Units from Maryland and Pennsylvania, including crews from Pleasant Valley, Littlestown, Westminster, Taneytown, Reese, Harney and McSherrystown volunteer fire departments responded, and the Carroll County Advanced Tactical Rescue Team was also on the scene to shore up the walls for safe entry by investigators.