A man has been arrested on suspicion of arson after three police officers suffered from the effects of smoke inhalation while evacuating a building.
Police were called to a "disturbance" and discovered a fire in a flat at Ship Wharf, Colchester. at about 01:30 GMT and alerted the fire service.
Officers evacuated the building and ensured all residents were safe.
The occupant of the flat, a 41-year-old, was taken to hospital for treatment and later arrested.
He is being held on suspicion of arson with intent to endanger life.
District commander for Colchester, Ch Insp Rob Huddleston, said: "This was an incredibly dangerous situation for all involved and, as they do on a daily basis, our officers have proved that they're not afraid to face peril to ensure that members of the public are protected from harm.
"It's very fortunate that no-one was seriously injured and the officers involved will be back on duty tonight, where they'll continue to police the streets of Colchester.
"My teams are continuing to work diligently to piece together the circumstances leading up to this morning's events."