At a news conference on Monday, CEO Henri Harland said the investigation to determine the cause of the blast that killed three employees and injured 18 others is still underway.
"There are no dangers of explosions as of now [according to] the interim report," said Harland. "The structure of the building is still under investigation. We will expect reports in the coming days. We don't have a fixed date for that."
According to Harland, an unfinished expansion to the plant was spared from some of the damage.
"This will really speed up the reconstruction process," said Harland. He added that the equipment and the structure still needed to be assessed before setting a deadline for reopening.
Neptune's chief operating officer Michel Chartrand said many questions will remain unanswered until investigators finish their work.
After the explosion, emergency workers set up a large perimeter around the site to ensure no one came in contact with acetone, a flammable chemical kept on the site in holding tanks.
Environment Quebec initially warned of toxic risks from the 15,000-litre acetone reserve, but authorities later said the fumes were not toxic.
Chartrand said the reservoirs have been emptied, but he could not report on the state of the pipes inside the plant, which may still contain chemicals.
Neptune makes health products from krill oil, a source of omega-3 fatty acids.
Harland said the company has set up three new working committees to attend to the victims' needs, including offering them psychological and financial help.
"We will be meeting with local authorities over the next few days, and we will continue to meet with employees on a regular basis," said Chartrand.
Sherbrooke Mayor Bernard Sévigny said he met Quebec Premier Pauline Marois on Thursday, and she assured him the government would help the company reopen its doors.