Mayor Drew said the act was intentional, but did not offer any speculation into what Ellam's motives might be.
WFSB saw the emergency room door pushed in with the auto inside as well as shattered glass.
Chief William McKenna said state police, Hartford and Federal Bureau of Investigation bomb squads are on the scene at Middlesex Hospital and at the driver's home. "It does not appear he made it into the lobby".
The Life Star emergency helicopter was dispatched to the scene.
One person was hurt, according to dispatchers.
After a man drove a vehicle into the emergency department of Middlesex Hospital on Thursday, other hospitals across the state are taking safety precautions.
'The bomb squads were there. They ordered nearby residents and pedestrians to take shelter in place, but lifted the mandate shortly after noon. Several homes in the area were evacuated as a precaution.
The suspect has always been known to local authorities, with a criminal record going back several years. His previous convictions include driving under the influence, criminal mischief, and assault. In 2013 he was also found guilty of attempting to strangle someone.
The hospital is in "emergency operations mode", hospital officials said. "Our emergency department is closed until further notice".
Eli Solomon '20 was among several hospital volunteers who were ordered to evacuate the premises after the incident.
"In view of witnesses' announcements, we trust he at that point set himself fire", Drew said.
The fire department was called to the scene to put out the flames, WTNH reported. "I found the volunteer coordinator and asked what was going on and she said that a vehicle had driven into the emergency room entrance and she just sent me home [because of the threat]".
Hartford Healthcare Officials said this is being done as a precaution at all six of their hospitals, but they do not believe there is any imminent threat at this time.