The blast took place at a condo building in the trendy Liberty Village neighbourhood, just west of the downtown core, on Monday evening and left one man with minor burns to his hands and face.
Andre Hagen, 36, was charged on Tuesday with one count of possession for the purpose of trafficking a narcotic, police said.
Police had said earlier in the day that the sixth-floor unit that was the site of the blast was suspected of being a drug lab, although they did not elaborate on what kind of drugs might have been involved.
The explosion blew out a number of windows and doors at the building and sent three elevators across from the unit down to the main floor.
Davida Gragor, who lives on the floor where the blast took place, said the building's fire alarms started going off around 6:30 p.m. on Monday.
"The alarm went off and it just kept ringing and ringing," she said. "You could smell some smoke."
Gragor recalled hearing a swarm of emergency vehicles pull up to the building before a fire official came over a loud speaker system and told residents to stay in their units unless they were hurt or their units were damaged.
The fire alarm that was in her hallway kept ringing for the next two hours while the alarm in her unit went off intermittently, Gragor said.
"We weren't allowed to leave our unit," she said. "I wasn't really scared, I was just in the dark as to what was happening, that was probably the most frustrating part."
Fire officials eventually declared the building safe, but Gragor noted that authorities were still working in and around the unit at the heart of the explosion on Tuesday morning.
"The hallway is just a disaster," she said. "It basically looks like a messy construction zone there's just white drywall everywhere."
When she heard that officials suspected a drug lab of sorts was behind the blast, Gragor said she was surprised.
"The condo building maintenance is pretty regular," she said, noting that building management had checked heating panels in all units just recently. "There's something at least once a month so for something to be going on undetected seems surprising."
Ontario's Fire Marshal's office is probing the cause of the blast and Toronto police are continuing their investigation into the incident as well.
Capt. Adrian Ratushniak of Toronto Fire Services said there was a "minimal fire" and a gas explosion had been ruled out.
It's estimated the blast caused about $120,000 worth of damage, he said.
Meanwhile, police have said that when they were first called to the blast, they feared the worst.
"When we first received the call, we thought we were going to have a lot of injuries with people in the elevators "cause of the loud bang," said Sgt. Jeff Zammit. "Fortunately we didn’t."