That’s according to the test results of 200 samples taken from different spots on the South Shore at different times of day between Thursday and Sunday.
It’s the latest development in a story that began last Wednesday when 28,000 litres of diesel leaked into the St. Lawrence River.
The spill happened after a pump generator leaked at a water filtration plant, causing diesel to infiltrate the ground and water.
The benzene levels in the water collected were below the norms set by the province.
Anomalies at 3 McDonald's franchises
The only anomalies detected in the water source were found at three McDonald’s restaurants on the South Shore, which are responsible for filtering their own water.
Bernard Gervais, the owner of the Boucherville McDonald’s franchise, said he had no explanation for higher rates of benzene. He said the water filter was changed after the water ban was lifted.
McDonald’s Canada said it will investigate but assured consumers it did not serve tap water or use fountain soft drinks at that outlet during the ban.
The city has been heavily criticized for the mismanagement of the fallout from the leak. It took hours for Longueuil to notify the Environment Ministry and even longer to inform residents of a water advisory.
Nearly 300,000 residents were affected by the resulting water consumption ban, which lasted two days.
Earlier this week, a Montreal lawyer announced he was taking steps to launch a class-action lawsuit following the drinking ban.