Emergency crews scrambled to deal with a gas leak at what CTV has learned is a Rideau Transit Group-related construction site only steps away from Parliament Hill this afternoon.
A 4-inch diameter line was breached by a subcontractor doing surface work to "beautify" the area - an effort connected to the LRT project - at about 1:30 p.m.
Buildings were evacuated in the area of Queen and O'Connor and a perimeter expanded all the way to Elgin and Sparks.
RTG says tunnel and surface-level workers in the area were among those cleared out.
This happened near the CTV Parliament Hill bureau.
Question Period producer Nicole Green says there was a loud boom and the odor of gas was immediate.
"We heard a loud bang and said 'that's the condo building,'" says Green who adds there have been construction-related blasts at the site often. "But this was a bigger than normal explosion."
"We looked down and saw construction workers running."
The leak was described as "very large" and "very difficult to stop."
Crews were still checking for gas pockets in buildings as of the late afternoon.
Ottawa Paramedics say no injuries have been reported at this time.
This made way for long delays for afternoon commuters.
OC Transpo buses were trapped in gridlock. People describe waiting 40 minutes to travel only a few blocks at a time.