A TOP fire chief said the service will not be bringing a prosecution against the joinery workshop at the heart of the Marlborough Road blaze.
South Wales Fire and Rescue group manager Mick Flanagan confirmed officers found no evidence that Limbright joinery breached fire regulations following the massive fire that gutted homes on the Newport street.
He said: "We gathered evidence at the scene and can confirm there was nothing wrong with the building.
"We will not be pursuing any prosecution as we have found no evidence fire safety legislation has been breached."
But he said exactly what went wrong with a chimney stack running through the building would probably never be known.
The Heath and Safety Executive yesterday refused to rule out their own investigation into the blaze.
Investigators are due to speak to fire bosses before deciding whether to look into the incident.
Police are not treating it as suspicious.
Superintendent Julian Knight said: "Early indications show there is no maliciousness. The fire started in a wood-burning furnace in which waste materials were burnt.
"The flue that would normally take the smoke out of the building was broke, and the flames leaked out into the roof area. It appears it was a tragic accident."
Gwent Police are also working out how much the operation cost them in man hours, overtime pay and extra supplies.
The force had 80 officers on the scene on Tuesday and Wednesday, some of whom were called from other divisions, including Caldicot, and six officers secured the scene on Thursday.
Superintendent Knight said there was a significant 'opportunity cost' for many officers as the fire took them away from dealing with their usual work and other calls.
He said: "It had a major impact on our service. It was two days in which officers could have been doing something completely different. What we now need to do is go back and attend to the calls we missed because of the fire."
The force also spent money supplying food, water and extra equipment such as breathing masks for the officers at the scene.