The Alberta Energy Regulator (AER) said on Friday a leak at a diluent pipeline at Suncor Energy Inc’s base plant near Fort McMurray, Alberta has been shut and isolated.

Suncor estimates about 20 cubic meters of diluent was released from the pipeline, according to the AER. However, the energy regulator could not confirm the estimate.

The pipeline is used for transporting diluent from Suncor’s base plant to its Firebag plant for blending with bitumen at its Firebag plant, AER said in an email.

Earlier on Friday, Suncor said it responded to a potential leak at its oil sands base plant in Alberta, Canada after it received a “notification from its leak detection system” at about 3 a.m. local time (0600 GMT).

The cause of the leak remains unknown and there were no reported injuries, the regulator added.

The AER said the incident occurred approximately 26 kilometers (16.2 miles) north of Fort McMurray, adding that the release has been contained and the clean-up was underway.

There has been no impact to operations as a result of this incident, Suncor said in a separate email.