It has been nearly two months since an explosion and fire sent plumes of thick black smoke high into the sky from the Irving Refinery in Saint John and the pieces are still being put together to solve the mystery of how it happened.

And one of those pieces is damaged piping taken directly from the blast site, a site that, until just a few weeks ago, was a “hot-zone” and off limits to investigators.

“The analysis of the piping, we'll be able to tell us whether the pipes were the cause or whether they were just the result of the explosion, so, it's what we're looking for and that's the unknown right now,” said Richard Blais of Worksafe NB.

The blast happened in the hydrodesulphurization unit at the refinery just after 10 o’clock in the morning on Thanksgiving Day and nobody was seriously hurt.

A stop work order from Worksafe NB on the specific unit is still active but has been modified.

“There's been some progress on that as well to allow for the safe access by the employer to the area,” Blais said.

The province is satisfied with the company's response after reviewing the emergency report, but at least one neighbouring resident is calling for more transparency.

Gordon Dalzell points to a newsletter he recently received from Irving Oil which says a debrief meeting was held on Nov. 1 with the community liaison committee.

“This information has not been made public, it's not on their website, why should just a few handful of invited community members get this information when the rest of the community deserves it as well,” Dalzell said.

The newsletter also says that the company has partnered with a third-party organization to help finish the investigation into the cause of the explosion and fire.

CTV News reached out to Irving Oil for an interview but did not receive a response.

The Worksafe NB investigation is expected to take several months to complete.

Whether the report will be made public, we're told they don't know at this time.

With files from CTV Atlantic’s Laura Lyall.