1984 - Barge

On June 15, 1984, a barge carrying 48 cargo containers overturned at the mouth of the Fly River in Papua New Guinea's Western Province. The barge was one of two being towed from Port Moresby to Kuinga where the goods were to be transported by road to the OK Tedi Mining site at Tabubil in the Star Mountain range for use in gold extraction.

The incident occurred in heavy seas 14.5km east north east of Umuda Island. The 48 cargo containers contained cement, hydrogen peroxide and sodium cyanide. The cyanide was carried in 15 containers each containing 180 drums. Each drum contained 100 kgs of sodium cyanide. One container opened releasing the drums.

On contact with water or humid air, sodium cyanide may produce poisonous and flammable hydrogen cyanide gas.

On June 15, 1984, a barge carrying 48 cargo containers overturned at the mouth of the Fly River in Papua New Guinea's Western Province. The barge was one of two being towed from Port Moresby to Kuinga where the goods were to be transported by road to the OK Tedi Mining site at Tabubil in the Star Mountain range for use in gold extraction.

The incident occurred in heavy seas 14.5km east north east of Umuda Island. The 48 cargo containers contained cement, hydrogen peroxide and sodium cyanide. The cyanide was carried in 15 containers each containing 180 drums. Each drum contained 100 kgs of sodium cyanide. One container opened releasing the drums.

On contact with water or humid air, sodium cyanide may produce poisonous and flammable hydrogen cyanide gas.

The National Emergency and Surveillance Co-ordination Centre was immediately notified. The Papua New Guinea Department of Defence sent a team of sixty persons to search for floating drums in the mangrove areas. All vessels carrying dangerous cargo were prohibited from passage on the Fly River. The mining company mobilized its health and security personnel for immediate action and, with the shipping company, attempted to salvage the lost containers and their contents. For this purpose, the mining and shipping companies hired a salvage company from Fiji to organize the salvage operation. Three fixed-winged aircraft and two helicopters took part in the search operation. The helicopters also landed at villages in order to warn the people about the dangers and precautions to be taken. A fourth fixed-winged aircraft fitted with a magnetometer searched the area. Of the released 180 drums from one container that had broken open, 140 drums were recovered. These included 3 empty drums whose contents had been released. Altogether, 14 containers (a total of 2,520 drums) and 40 free drums were not recovered. That is, containers and drums holding 256 tonnes of sodium cyanide were lost. Search operations were intensive for some time but were scaled down after investigations showed that no more drums could be found. However, weekly surveillance for the lost drums continued for some time.

The spillage created alarm among the local people and they refused to eat fish or drink water from the river. Schools in the area were closed for two months because it was feared that school children travelling by boats could be poisoned by contaminated splashes and water spray from the river or that fatalities would occur if a boat capsized in polluted waters. The authorities were compelled to react to the needs of the villagers and food was supplied to them.

A ban was placed on prawn fishing and on the marketing of non-gill netted fish in order to prevent any adverse effects on Papua New Guinea's international fish and prawn market (the area produces about 4% of the country's yearly prawn catch). In spite of fears that overseas buyers might place a ban on marine exports, none took place. The authorities estimated that approximately 2,000 fishermen and their families had been affected. Some of these protested against the authorities for the ban of fishing imposed and subsequent withdrawal of their livelihood. The authorities of the province made a strong case for the payment of compensation from the national Government.

Laboratory tests on water collected near the accident site showed that cyanide under similar conditions equivalent to those existing in the water column would have a half-life of approximately 10 hours. Therefore, any quantity of cyanide mixed with water would be halved every ten hours by abiotic and biotic degradation. Scientists also considered the probable fate of cyanide in the marine environment under two scenarios: 1) a rapid release; and 2) a slow release. A rapid release could result from a sudden rupture of the container and drums so that all the cyanide from a full container load would be dispersed in the water. A slow release would result from the corrosion of a container and drums with the sodium cyanide slowly mixing with the water. Mathematical models were run and toxicity thresholds for both acute effects (death) and chronic effects (inhibition of the development of larvae) were pre-determined. Water circulation and movement in the area was simulated by a computer model. The results showed that under conditions of rapid release, i.e. all cyanide from the container is dispersed within 25 hours, acute effect levels would extend up to 8kms from the point of release and chronic effect levels would extend up to 25kms from this point. In a slow release, the acute effects would be felt immediately near the containers (within 50 - 100 metres) while chronic effect levels would be felt a few kilometres away.

The scientists concluded that the effects of cyanide in seawater would probably be transitory because cyanide is quite reactive and forms thiocyanate which is not considered harmful in the aquatic environment although one fish kill of 1,500 fish had been reported after the accident. The scientists concluded that the most adverse release of lost cyanide in the marine environment from a drum would cause small ecological damage compared with the human risks should a drum rupture when caught in a trawling net or if washed ashore.

Recent experimental studies have also shown that peroxide in industrial formulations could become a routine cure for fish kills caused by cyanide spills. In theory, the addition of peroxide should raise the pH (lower the acidity) of the polluted water, causing the cyanide to break down more rapidly. The use of peroxide in the field remains experimental, nevertheless it has been used in the River Wey cyanide spill in the U.K.