Nine people were killed in the blast

The Crown Office said ICL/Stockline Plastics was able to use the building again, but the inquiry was continuing.

Five men and four women were killed and dozens injured in the blast on 11 May, the cause of which remains unknown.

A spokeswoman for the company welcomed the news, but said it would take some time before it could trade normally.

Earlier this month, company management asked the Health and Safety Executive and the procurator fiscal to hand over machinery at the blast site in order for some staff to resume production.

Our immediate efforts will be to reinstate power, services and the necessary communications that will make going forward possible ICL/Stockline spokeswoman

In a statement, the Crown Office confirmed the building and some machinery had been passed back to its owners.

It said: "Investigations into the cause of the explosion are continuing.

"However, the investigating authorities - the procurator fiscal, Strathclyde Police and the Health and Safety Executive - have confirmed they have no further interest in this building and, accordingly, have handed control of the building and its contents back to ICL Plastics.

'Ongoing investigation'

"In the course of the investigation so far, the procurator fiscal has been able to co-operate with a number of requests from the company for the return of items needed to run their business.

"Future requests will continue to receive careful consideration and, where the items are not considered essential to the ongoing investigation, they will be returned."

Investigators have pored over the factory site

A spokeswoman for the company said it would be some time before it could operate at full capacity.

"We welcome the news that control of the Stockline business premises and its contents will be handed back by the investigating authorities," she said.

"It will take some time before we can accurately say when we will be able to resume any significant level of operations at the Stockline building.

"Our immediate efforts will be to reinstate power, services and the necessary communications that will make going forward possible."