**Title: Four Critically Injured in North York Condo Gas Explosion**

Four construction workers sustained life-threatening injuries in a gas explosion at a North York condominium site on Tuesday morning. The incident occurred around 9:15 a.m. in the boiler room located at the penthouse level of the building on Esther Shiner Blvd. and Provost Dr.

Emergency services responded quickly to the scene after receiving reports of the explosion. Firefighters found multiple injured individuals upon arrival. "On arrival, there was no fire here, but crews were met with multiple patients and initiated requests for EMS units to attend," said Paul O’Brien of Toronto Fire Services. He noted that some patients exhibited signs of burns, but there was no active fire when the fire department arrived.

In total, seven workers were injured in the explosion. Four of them were transported to trauma centers with critical injuries, while three others were treated for minor injuries. All individuals affected were employees working at the construction site.

The explosion's cause is currently under investigation. The Ministry of Labour is leading the inquiry, with assistance from Toronto fire marshals. O’Brien remarked on the rarity of such serious incidents at construction sites, stating, "We do not attend a lot of calls like this, of this serious nature, in construction sites. But I cannot recall in the last couple of years something to this nature."

Authorities have closed roads in the vicinity as they continue their investigation. Toronto EMS Chief Bikram Chawla mentioned that he could not disclose specific details about the injuries due to privacy concerns. O’Brien also indicated uncertainty regarding the number of workers present at the time of the explosion and when operations might resume at the site. "The investigation is just in the initial stage, so I’m not sure when the (workers) will be able to get back into the building," he said.