Up to 31,500 litres of acid has leaked from a train which derailed near Julia Creek in north-west Queensland on December 27, according to police.
A locomotive and all 26 wagons it was towing derailed around 20km east of Julia Creek at roughly 10.20am on December 27, 2015.
The train, operated by Aurizon, was believed to be transporting roughly 817,000 litres of sulfuric acid in wagons belonging to Incitec Pivot.
Three crew on board the train were reported to have sustained minor injuries and were transported to a nearby hospital.
According to Queensland Police, one of the derailed wagons is likely to have ruptured, leaking as much as 31,500 litres of sulfuric acid, which typically has a pH of 1 or lower. The most extreme acids have a pH of close to 0, while a pH of 7 is neutral.
Testing after the derailment on nearby Horse Creek by staff from the Department of Environment and Heritage Protection found the river had a pH of close to 3 at at least one site, with the river only returning to neutral pH levels three kilometres downstream.
“This tells us some of the sulfuric acid has made its way into the waterways,” minister for environment and heritage protection Dr Steven Miles said.
“Acidic water is a concern because it can kill fish and riparian [riverside] vegetation.”
Workers are using limestone (which typically has a pH of roughly 8) to neutralise water and land around the site.
“Response crews have accessed locally sourced limestone which will be aerially applied to the area,” Dr Miles said on December 31. “Lime filled sandbags will also be placed across Horse Creek to treat flows already in the creek.
“Adding limestone to waterways is considered safe and effective, and has been used for many decades to treat waterways with acidic water.
“We will continue monitoring and providing advice as to how best address any environmental impacts.”
Acting under the Public Safety Preservation Act, the Queensland Police Service initially designated a two kilometre exclusion zone around the incident, closing the Flinders Highway in both directions between Julia Creek and Richmond.
The exclusion zone was reduced to 50 metres on January 1, allowing the highway to be re-opened.
The Queensland Government announced an independent investigation by the Australian Transport Safety Bureau would take place.
“While it is too soon to speculate on the cause of the derailment, by engaging the Australian Transport Safety Bureau in these early stages, we can ensure the incident is thoroughly investigated and that we receive the best advice in a timely manner,” transport minister Stirling Hinchliffe said.
A preliminary report into the incident is expected by the end of February. A full report and recommendations will be released by September, Hinchliffe projected.
“Further details about the extent of damage to the infrastructure and the timeframes for the track reopening will be available once the recovery crew has access to site,” he added.
Freight trains and the Inlander passenger service on the Mount Isa line continue to be impacted as a result of the incident.
“The recovery of the line will be a complex and lengthy process, but our crews are working hard to resume train services as quickly and safely as possible by building a temporary rail track around the crash site,” Queensland Rail reported.
As of 9am on Saturday, January 2, the locomotive and all 26 wagons remained on their side, and the track remained closed.
“Aurizon have advised they will attend to the recovery of their locomotive and support Incitec Pivot in the recovery of their wagons and product,” Queensland Rail said. “Aurizon and Incitec Pivot will ensure their recovery work happens safely and without environmental impact.”