Oil board took too long to disclose N.L. spill: NDP

Provincial NDP Leader Lorraine Michael is questioning why people weren't told earlier about a spill of 26,000 litres of synthetic drilling mud from the Henry Goodrich drill rig east of St. John's on Monday.

She said it's unacceptable that the public found out Thursday, three days after it happened.

The Canada-Newfoundland and Labrador Offshore Petroleum Board said it needed time to verify the information before disclosing it publicly.

Information about the incident was posted on the offshore petroleum board's website Thursday.

The Henry Goodrich rig was drilling an exploration well for Suncor when the incident happened.

C-NLOPB spokesperson Sean Kelly described it as a significant spill.

"It certainly does have an impact on the environment that we consider serious. We need to continue with the investigation to find out what those impacts are," said Kelly Thursday.

Drilling mud is used in the industry to prevent oil or gas from escaping during drilling operations.

Studies have found that a common drilling mud additive, used as a thinner, can harm fish eggs and fry. Other mud additives have reported effects on marine organisms, including reduced fertility and higher mortality.

Kelly said Thursday that depending on the outcome of the investigation, there might be charges.

He said it appears the drilling mud was released from a valve on the rig that was left open.

According to the C-NLOPB Monday's incident is the largest spill of drilling mud since 2007.

The board said there was a 74,000-litre spill of drilling mud in the Orphan Basin area during January 2007.