Police are investigating a huge inferno which has engulfed concrete tanks full of old tyres near the intersection of two highways in regional South Australia.
The fire at Lincoln Gap on the upper Eyre Peninsula has been contained after ripping through tyres and other potentially hazardous materials in 15-metre-high tanks, but the blaze sent up large amounts of smoke and fumes.
Firefighters were called to the scene at a rest area near the intersection of the Eyre and Lincoln highways about 1:40am on Thursday.
The site, known as "The Tanks", is a local landmark and is about 26 kilometres south-west of Port Augusta.
"On arrival patrols located two large tanks fully engulfed, the tanks are full of old tyres," police said.
Crime scene investigators deemed the fire suspicious, and police have warned drivers the smoke is significantly reducing visibility.
Six CFS and three Metropolitan Fire Service (MFS) trucks attended the scene where both highways were partly closed to traffic.
The CFS said there was no fire threat to the nearby township but earlier advised locals to "remain indoors where possible, with doors and windows closed".
"There are discarded tyres amongst potentially unknown miscellaneous materials within the 15-metre-high tanks causing high flames and thick black smoke to be produced," the CFS said.
"The rail network is also being communicating with them due to the nearby train line, although there is no direct threat and trains are able to proceed with caution."
Police have asked anyone with dashcam footage or information to contact Crime Stoppers on 1800 333 000.
There are five tanks in total at the site, all of which are about 40 metres in diameter.
A heatwave warning has been issued for almost all of the state by the Bureau of Meteorology (BOM).
Temperatures across South Australia are expected to soar above 40 degrees Celsius across parts of the state today, with 45C forecast for Nullarbor in the remote west and 41C forecast for Adelaide.
"It's been a very hot night, that's for sure, so if people are waking up a little bit cranky or a a little bit grumpy, there's good reason for it," senior meteorologist Simon Timcke told ABC Radio Adelaide.
"We dropped to 26.1C at 6:41am for our minimum but it took until the early hours of the morning before the temperature dropped below 30C, so quite an uncomfortable night and a very hot day ahead of us."
Fire weather warnings are in place for five districts: West Coast, Eastern Eyre Peninsula, Lower Eyre Peninsula, Mount Lofty Ranges and the Upper South-East.
Yesterday evening, the MFS responded to an industrial fire on Coglin Street at Hindmarsh in Adelaide's western suburbs.
Firefighters were called to the scene about 6:10pm.
Flames spread from crates to a nearby commercial building, but the blaze extinguished within 20 minutes by 34 firefighters.
The MFS was also called to a vehicle fire on Gawler Terrace, Walkerville, about 9:15pm.
A Nissan Pathfinder had been stolen minutes earlier from Vale Park and was completely destroyed by fire, police said.
