Inflammable Dust Hazard

Press, Volume CIV, Issue 30783, 22 June 1965, Page 3

Inflammable Dust Hazard

(New Zealand Press Association)

WELLINGTON, July 21. The firm of General Plastics (N.Z.), Ltd., obviously did not appreciate the hazards of inflammable dust, a witness told the commission of inquiry into the fatal explosion at the firm’s Masterton factory on April 13.

The commission resumed the inquiry in Wellington today after adjourning from Masterton in May.

It comprises Sir Arthur Tyndall, Dr. T. Hagyard and Mr J. Graham. The counsel assisting the commission is Mr G. S. Orr. Four were killed in the explosion and six injured.

Three expert witnesses to day rejected a suggestion that a smell reported at the factory since the explosion might indicate it was caused by gas.

The Chief Inspector of Explosives, Mr E. L. Sellens, said the rarity of dust explosions in New Zealand was the reason for the lack of controls safeguarding against them. He said all the evidence pointed to there having been an atmospheric explosion under the floor of the orna menting and women’s locker rooms at the factory and to a lesser extent in the rooms There was no evidence to suggest any inflammable gas or vapour was present, he said.

“The obvious possible source of material for an atmospheric explosion was the dust known to be present.”

Under Floor Dust must be presumed to have accumulated under the floor, he said. It was possible the dust was fed into the exhaust ducting from the operation of a machine. Several sources of ignition were possible in the circumstances, including a spark from machinery or a cigarette.

“I think it most likely an accumulation of polyester and casein dust had been caused to heat up and smoulder until sufficiently hot to ignite a dust cloud coming into contact with it,” said Mr Sellens. He said he thought the most likely source of smouldering material was a cigarette butt. “It is obvious the firm did not appreciate the hazards of inflammable dusts and had therefore done nothing to guard against them. “However, in this respect they are in no different position from the large majority of manufacturers in this country, where the record of dust explosions is extremely low.”

He said Government controls to safeguard against dust explosions might be necessary. However, these were so rare over the years that this had suggested that special legislative control was not justified.

“Nevertheless, the recent accident does raise this question,” he said. Later Smell

The Dominion analyst, Mr P. J. Clark, reported on an investigation of the plastic factory for gases on May 25 (six weeks after the explosion) when a smell was present similar to that which had been noticed before the explosion.

“There was no evidence whatever of the presence of any gas under the building which could give rise to an explosion,” he said. The inquiry is expected to finish tomorrow.