An air tanker dropped retardant in the city of Canberra, the capital of Australia on February 4.
The aircraft was working on the Orroral Valley fire in Namadgi National Park in the Australian Capital Territory (ACT). The ACT Emergency Services Agency said the aircraft “encountered turbulence causing 2,500 litres of retardant to be released on Parkes Way.” A number of cars were coated with the retardant, and judging from the photo below, at least one person.
The fact that 2,500 liters (600 gallons) were released leads one to guess the aircraft may have been a Single Engine Air Tanker, unless it was a partial load from a large air tanker.
The turbulence could have forced a low flying air tanker to suddenly and unexpectedly lose altitude, and the pilot might have jettisoned the load in order to help regain altitude and control. Or, the G-forces produced stress causing the tank doors or other hardware to fail. Regardless, we are happy that retardant was the only thing that fell out of the sky on Tuesday.
ACT Fire & Rescue worked with the Environmental Protection Authority to assess the situation at the impacted area which included the carpark at Rond Terrace and Anzac Parade at Rond Pond.
The retardant was close to the National Emergency Services Memorial and about a mile north of the Parliament House at the capital.
(UPDATE, Feb. 10, 2020: More information has become available about the cause of the retardant drop)