A massive inferno at an NT Health medical supplies warehouse in Berrimah on Sunday has forced the government to issue a “Code Brown” as they frantically determine the extent of the loss, with early estimates from the toxic fire pegging the damage at $30 million.

Emergency crews were alerted to the blaze around 10:30am on College Road in Berrimah as thick, toxic smoke emanated from the building that was used for stocking medical supplies for the Darwin, Palmerston, Katherine and Gove hospitals.

It was reported oxygen tanks exploded in the fire, along with other medical supplies, while crews raced to move nearby fuel tanks from the immediate area.

Chief Fire Officer Mark Spain, who has had trouble staffing fire stations of late, told reporters that 28 firefighters had rushed to the scene along with the “Bronto” fire truck to contain the fire with “toxic smoke” created from the explosions.

“We expect this fire, given the location of it and the structural integrity of the building, it will take two or three days before we can get on top of it,” he said.

“It’s very early at this stage to determine how it started.”

NT Health said in a statement on Sunday that a “code Brown” had been called, which they said was necessary when an “external incident” requires a “system-wide response”.

“The Code Brown has been declared whilst it is established what supplies have been impacted,” the statement said.

“The NT Health Incident Management Team has been established and is working to conduct a stocktake across its hospitals and health facilities to determine the level of medical supplies immediately available for patient care.

“All hospitals remain open at this time and no patient services will be impacted.”

Public records show the non-descript Berrimah building that caught fire is owned by Moranidini Earthworks Pty Ltd and was leased to the NT Government in possibly November 2018 for annual rent of slightly more than $356,000 and was set to expire in October 2024, with options to extend.

It was not immediately clear if the building was one of the more than 300 government-owned or leased properties the ICAC is currently investigating for failing to have proper certification.

The cause of the blaze is under investigation.