A planned explosion that brought down part of the old Port Mann Bridge early Wednesday morning is raising environmental concerns.

The massive blast sent one of the bridge’s seven concrete footings into the Fraser River, and shot a large volume of water and dust from the epicentre.

The Transportation Investment Corporation, the Crown company in charge of the ongoing bridge demolition, said a number of measures were used to protect sturgeon and other fish in the river.

Those assurances are little comfort to the head of BCIT’s Rivers Institute, however, who worries there aren’t enough watchdogs keeping tabs on the project.

“There isn’t much government regulatory oversight on the environmental file compared to what it used to be 10 or 15 years ago, and that is a concern,” Ken Ashley told CTV News.

“In British Columbia, where people care about the environment… there’s a fiduciary responsibility that government should be looking after these things.”

The Ministry of Transportation, the Ministry of Environment and TIC refused to comment on the demolition Wednesday, leaving important environmental questions unanswered.

A release on the demolition outlines some of the safety measures taken, including methods of scaring away fish prior to explosions.

“Concrete vibrators and small blasts, called scare charges, are set off to frighten any fish away from the area,” it says.

Bubble curtains are also set up to dampen potentially harmful shockwaves, and the blasting is timed to minimize potential risk to fish, according to the document.

More demolition explosions are expected as crews take down the remaining concrete footings.

With a report from CTV Vancouver’s Scott Hurst