Scientist Ian Jones doesn't have faith in the C-NLOPB's ability to investigate offshore oil spills. (CBC)

A scientist is calling for an independent investigation of offshore oil industry spills after a three-day delay in the reporting of the release of synthetic drilling mud from a rig east of St. John's.

"Generally I feel kind of angry and kind of cheated by the [Canada-Newfoundland and Labrador Petroleum Board's] response," said Memorial University of Newfoundland biology professor Ian Jones.

"We deserve proper independent regulation and transparency and a proper explanation of what is going on and we are not getting it," said Jones.

The board, which regulates the oil and gas industry in Newfoundland and Labrador, said on March 31 that 26,000 litres of drilling mud was spilled from the Henry Goodrich rig while it was doing exploratory work for Suncor on March 28.

"The board sat on it for three or four days before talking about it and then the information produced is very sparse and some of it frankly, is quite questionable," said Jones.

An official with the board said it is investigating the impact of the spill. He said drilling mud usually sinks to the ocean floor.

'I guess we have to trust whatever the company says' —Ian Jones, Biologist

Jones fears the impact of the spill may be greater than C-NLOPB officials suggested.

"Is this just speculation by the C-NLOPB? Where is the aerial surveillance on this? Where was the response to this spill by experts to document what actually happened? I guess we just have to trust whatever the company says," he said.

Jones said a smaller spill of drilling mud back in 2004 resulted in a large slick on the ocean surface. He said oil on the ocean's surface can harm seabirds.

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.

The C-NLOPB said it appears the drilling mud was released from a valve on the rig that was left opened.

The board is facing criticism from both Jones and the provincial government.

Newfoundland and Labrador's Natural Resources Minister Shawn Skinner said Monday the board should not have waited a few days before it reported a spill of synthetic drilling mud.

According to the board, Monday's incident is the largest spill of drilling mud since 2007.

The board's website says 74,000 litres of drilling mud were spilled in the Orphan Basin area of the North Atlantic Ocean in January 2007.