Drilling mud spills on oil rig

Several thousand litres of drilling mud spilled on the deck of a rig working at an offshore oil field southeast of Newfoundland, regulators have reported.

The Canada-Newfoundland Offshore Petroleum Board said about 4,000 litres of synthetic mud spilled at the GSF Grand Banks on Friday.

Husky Energy reported the spill. The rig has been doing work at the White Rose field.

"Operations were suspended when the incident occurred and clean-up response was initiated. It currently appears that little, if any, mud was spilled to sea," the board said in a statement posted to its website.

The board said a survey from a nearby ship "observed no sheen or discoloration on the surface" of the ocean.

Drilling mud is used to lubricate drill pipes and to balance pressure in the reservoir. The CNLOPB describes synthetic-based mud as "a food-grade oil of low toxicity."

The spill comes on the heels of the late March spill of nearly 26,000 litres of drilling mud at the Henry Goodrich rig, which sparked controversy because it was not reported publicly for three days.