SYDNEY, AUSTRALIA—Floodwaters were hampering emergency officials’ efforts on Monday to clean up a remote site in northeast Australia where a freight train carrying sulfuric acid derailed a day earlier.

The train was carrying around 200,000 litres of the highly corrosive acid when it derailed near the small town of Julia Creek in western Queensland state on Sunday, police said in a statement. A small amount of acid and diesel fuel spilled and all 26 carriages came off the tracks, police said. Three people were treated for minor injuries.

Heavy downpours were making clean-up efforts difficult on Monday, with flash flooding cutting off access to the highway adjacent to the derailment site.

Officials set an exclusion zone of 2 kilometres around the site and were trying to determine whether there had been any impact to the environment, though police Inspector Trevor Kidd noted the area is very remote.

“It is some significant distance from major waterways and any major infrastructure, so we do have something going our way as far as that goes,” Kidd told the Australian Broadcasting Corp. “But it is certainly challenging to make an effective assessment at this stage.”

Queensland Rail, the state’s government-owned railway operator, said the flooding had prevented it from reaching the site, so it did not yet know the cause of the derailment or the extent of damage to the track. It expects the track will remain closed for several days.