UPDATED at 4:30 pm on 4/22/16

Imperial Oil of Canada is still tracking chemical levels in the St. Clair River after a spill earlier this week.

The company announced that Tuesday night an unknown amount of low-concentration hydrochloric acid overflowed into the river. Testing shows no negative impacts, the company said.

Jon Harding, community and Aboriginal affairs adviser for Imperial in Sarnia, said because the spill is small and tests haven't found hydrochloric acid in the river yet, there's no need for a cleanup. But Imperial will continue to monitor the river.

"We were monitoring the water quality during and after the event as a precaution, and in that monitoring we did not identify any hydrochloric acid," he said. "No impacts have been identified downstream of the release."

Harding said the company quickly alerted Ontario’s Ministry of Environment and Climate Change and the Canadian Coast Guard, as well as anyone using the water downstream.

Environmental officials said they "do not anticipate impacts on water treatment plants further downstream."

Congresswoman Candice Miller, R - Macomb County, issued a statement about the spill Friday, advocating for enhanced monitoring of the river to track possible environmental hazards.

"We are reminded of threats posed by such spills and of the need to revive a monitoring system that provides residents with the assurances they deserve,” she wrote.

Imperial sometimes uses hydrochloric acid for cleaning at their facility, Harding said. The company is still investigating the cause of the spill.

CORRECTION: An earlier version of this story misidentified Congresswoman Miller as a member of the Michigan Statehouse.