Section of Toronto’s financial district remains closed after hydro vault explosions

A section of King Street just west of Yonge Street in Toronto’s financial district will remain closed for most of the day following a series of explosions during the evening rush hour on Monday.

The blasts, blamed on an overheated hydro vault fire, shut down the area at about 5 p.m. and sent commuters scrambling. There were no reports of any injuries.

Thick black smoke was seen billowing from a set of sidewalk grates in front of a Royal Bank office building near King and Yonge.

Toronto Hydro said crews have been working through the night to conduct repairs to the vault. However, workers were forced out just after midnight when they noticed smoke.

“We determined that it was a conduit that was leading down into the transformer that was smoking,” Toronto Fire Platoon Chief Kevin Aucoin said. “The crews backed out and our guys put small amounts of water and CO2 trying to contain it.”

WATCH: Toronto Fire and Toronto Hydro investigating cause of underground hydro vault fire that erupted Monday afternoon at King and Bay. Ashley Carter reports. (May 1)

1:53 Toronto fire and hydro investigate cause of downtown fire

Fire official said firefighters remain on standby just in case there are any flare-ups.

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“The problem is we have a live transformer next to a transformer that is blown,” Aucoin explained. “We have to be very careful not to use too much water so that we could have a problem with the backup transformer beside it — that’s powering the backup generators right now.”

Hydro officials said the vault had to be “de-energized” last night before crews were allowed to pump the rain water out and conduct repairs.

“We went in and we know the area is severely damaged. Yesterday there was a lot of rainfall, so that is a potential culprit here,” Toronto Hydro spokesperson Brian Buchan said. “If the vault did flood, then that would be devastating for the vault itself.”

READ MORE: Hydro vault fire in downtown Toronto to blame for heavy smoke, underground explosions

Toronto Fire Platoon Chief Kevin Shaw said the fire was smoldering early Tuesday morning as firefighters attempted to extinguish it without damaging the transformer, which powers Royal Bank’s computer system.

“So we cannot get water on that,” Shaw said earlier in the day. “We tried CO2 and small amounts of water. If that’s not successful then we’ll stand by until Royal Bank has some IT people coming in and they’ll do whatever they have to do to secure their computer systems.”

Hydro officials said the plan is to reroute the power to the building temporarily until the broken transformer is replaced.

“That would get the customer back on and in the meantime then we would do a permanent fix that would take some time,” Buchan said.

9:42 Toronto Hydro says scene of downtown explosion remains very active

• Toronto Hydro says scene of downtown explosion remains very active
• Underground explosions force closure of busy downtown Toronto streets
• Toronto fire and hydro investigate cause of downtown fire

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The vault explosions shut down the King subway station on Monday and caused several streetcars to take detours.

Both the 504 and 514 routes continue to be diverted on Tuesday.

The underground PATH system was also evacuated including the buildings adjacent to the explosions.

Fire officials said the Royal Bank building will remain closed for the day while other businesses in the area are open.

-With files from Nick Westoll