It happened around 1:00 p.m. at the Woodcare complex on the 900 block of Cedar Tree Lane.
Heavy fire was reported upon arrival.
A 50-year-old woman was hospitalized with smoke inhalation, and more than 20 residents were forced from their homes.
The flames were brought under control around 1:30 p.m.
Officials say damage to the building has been estimated at $150,000.
The Associated Press contributed to this article.
