The Townsville Bulk Sugar Terminal was built in 1958 and could hold 10% of Australia’s annual sugar production. On 9 May 1963, the sugar in shed caught fire. Black smoke blanketed the city and a thick, black molasses-like ooze of melted sugar poured into creeks and the harbour.
Fire services were brought in from Cairns, Ayr, Innisfail and Proserpine, and fire fighting volunteers from Inkerman, Kalamia and Pioneer sugar mills. The Townsville Regional Electricity Board, Army, Royal Australian Air Force and even the visiting destroyer USS Somers provided extra pumps. The fire blazed for 5 days and caused £6 million damage, around $170 million in today’s prices. It was the biggest structural fire in Queensland’s history. 77,500 tons of sugar destined for Japan was lost.
But that wasn’t the end of the story. Things could have been much worse.
On 16th May, minor explosions were felt under the feet of crews cleaning up the rail sidings on the western side of the building. Further explosions were felt over the following two days. Then on the afternoon of the 18th, a circuit breaker in a nearby switch room dropped out and an explosion lifted the checker plate of the floor above, blew the window out of the door and even displaced some earth outside. Engineers on site concluded that some sort of gas was present. The Inspector of Coal Mines at Rockhampton, Charles McPherson, was rushed to Townsville with gas detecting equipment.
One test showed that no methane was present but a second instrument showed a methane level of minus 1.5%. This was impossible. The instrument was checked and cleared, and showed zero in clear air. When taken back into the switch room it again showed minus 1.5%. One of the scientists on site explained that this could occur when hydrogen was present. Clostridium bacteria in the soil could produce hydrogen under favourable conditions, such as being fed by water and sugar. Gas was then found bubbling through water in open pits on the eastern side of the building.
Samples were taken and flown to Brisbane for further analysis. This confirmed that hydrogen was present in explosive concentrations in all the main drains, enclosed areas and anywhere else sheltered from the prevailing breeze. Holes were drilled through the 16 inch thick concrete floor and again explosive concentrations of hydrogen were found.
In his report, McPherson wrote that:
It is my opinion that the emission of such quantities of hydrogen … was formed under exceptional conditions due to the sugar fire and copious volumes of water on the sugar to quench the fire. The resultant mix saturated the whole area of reclaimed swamp land which acted like a huge sponge holding the mixture in which the bacteria multiplied profusely.
QSA Item ID 2583755
The water table under the Terminal varied with the season but was typically around 7 feet below ground level in the dry season. The water table had risen to 2’6” below ground level after the fire from the huge quantities of water used and the water contained around 1.5% dissolved sugar.
This required a radical rethink of the design of bulk sugar terminals, in particular improving ventilation of confined areas, keeping drains clear of water, adding fans to the conveyor taking sugar from trains to the storage shed and how to deal with any spillage.
Over the coming months, similar gas tests were carried out at Bundaberg, Mackay and Mourilyan bulk sugar terminals but no explosive gas was detected. The difference was these terminals had been built on bedrock, whereas the one at Townsville was built on porous soil. The Department of Mines billed Townsville Harbour Board a total of £73/4/1 for the testing, a small price to prevent a catastrophic explosion.