Montreal firetrucks have historically arrived at the scene of a blaze after about four minutes and twenty-nine seconds.

But in July and August that arrival time rose by 30 to 40 seconds.

The city accuses the firefighters' union of rolling slower as a pressure tactic in their ongoing pension dispute.

Firefighter union chief Ronald Martin angrily refuted that claim when interviewed by CTV Montreal Friday, saying that the many summertime road construction delays are likely to blame for any later arrivals.

"What the numbers show is that they’re going up but what doesn’t’ show is why they’re going up,” said Chris Ross, vice president of the Montreal Firefighters Association.

Eight hours of meetings in front of a mediator Friday failed to see both sides come to terms.

The process has since been transferred to a commissioner who is expected to come up with a decision on whether to forward the case to the Labour Relations Board.

Mayor Denis Coderre was playing down any sense of alarm that might have resulted from the notion that firefighters wouldn't be pressing forward at top speed to quell blazes.

"Security is not at stake. It’s a matter of working relations, bargaining agreements, and that’s why we’re in front of the council this morning (Friday),” said Mayor Denis Coderre.