Saint-Hyacinthe could be to blame for thousands of dead fish in the Yamaska River

The City of Sainte-Hyacinthe saidit could be responsible for the death of thousands of fish in the Yamaska River.

Mayor Claude Corbeilsaid helearned Monday morningthat the expansion of a water treatment facility could be to blame.

Urgence-Environnement said some fish were found in the bottom of the river, discoloured and in an advanced state of decay on Friday after residents alerted authorities last week.

• Thousands of fish found dead in the Yamaska River

The construction work carried out at the facility onJune 28sent an overflow of waste water into the river.A high concentration of microbodies in the waste watercombined with low levels in the river could be what killed the fish, according to the city.

"There is obviously a series of bad decision from the city's administration with this file," Corbeil said in a statement.

An internal investigation is underway.