Project Caymus fuel tanks built unlawfully in Darwin for US military not designed to withstand major cyclone

Australia Broadcast Center

27-05-2025

Eleven massive fuel tanks built for the US military to contain 300 million litres of flammable and combustible liquid on Darwin Harbour are not designed to withstand a category three cyclone.
The findings are contained in an engineering report and can be revealed after the ABC reported the tanks were constructed unlawfully, without a building permit.
Touted in 2021 as a "pivotal project" for US defence operations based out of Australia's north, the $270 million Project Caymus fuel storage facility was meant to be operational by September 2023.
The tanks have never held fuel though, in part because water is intruding into their base.
US company Crowley owns the facility, having won a US government tender to build it on Northern Territory government land.
Two subcontractors which consecutively held the role of lead builder — Australia-based Saunders International and US-based Latitude 63 — have both had its contracts terminated by Crowley.
The engineering report, obtained by the ABC, was completed in December 2023 by the project's building certifier at the time, Darwin firm Acer Forester.
It was commissioned by Latitude 63 and based on advice from the principal structural engineer at Adelaide-based company Fyfe.
The report includes an assessment of the "importance level" for the tanks, as per the National Construction Code (NCC).
An importance level is designated for all structures in Australia and is based on the consequences of a structure failing during a natural disaster such as a cyclone.
The report shows the tanks on Darwin Harbour should be classed at importance level four, the highest classification, for structures "containing hazardous materials capable of causing hazardous conditions that extend beyond property boundaries".
Instead, the tanks were initially designed at importance level two, the classification for a car garage, shed or suburban backyard workshop.
And before construction began, the plans were altered to reduce the tanks' wind durability below importance level one.
"[Crowley] specified that the tanks be designed at a design wind speed of [249.5 kilometres per hour]," the advice from Fyfe said.
"However, the tank[s] were designed to a [193.5 kilometres per hour] design wind speed.
"This error was embedded within the Saunders International computer calculations, where it would have been difficult for [Crowley] to discover."
According to the Bureau of Meteorology, gusts during a category three cyclone can reach up to 224 kilometres per hour.
In 1974, Severe Tropical Cyclone Tracy destroyed Darwin with wind gusts reaching 217 kilometres per hour before wind-recording instruments failed.
A cyclone has not hit Darwin since construction began on the Project Caymus fuel tanks.
The report also noted that an April 2023 document prepared by Saunders that "certifies" the design of the tanks was "not acceptable".
Saunders International did not respond to specific questions from the ABC about issues raised in the report.
Instead, it provided a statement saying: "Saunders left the site in April 2023, having completed construction contract requirements in full compliance with relevant codes, practices and permits."
"The tanks were constructed to the specifications provided by the owner and their appointed engineer," the statement said.
"We refer you to Crowley, the owner and operator, for any further inquiries."
In the report, Fyfe also advised of the dangers associated with the tanks' inadequate design.
"Failure of the tanks in a cyclonic wind event could result in over 200 million litres of flammable and/or combustible liquid becoming uncontained," the report said.
"[This would cause] hazardous conditions beyond the property boundaries and to significant population areas and strategic facilities.
"[It would] have catastrophic consequences on people, property and the environment."
In its findings, Acer Forester said the lives of Darwin residents would be at risk if the tanks failed during a cyclone while operational.
"The impact on the public (including environmental damage) would be at least substantial, if not extreme."
In a statement, Latitude 63 said it presented the report to Crowley, which subsequently "removed Acer Forester from the project".
Latitude 63 said Crowley also amended their contract "to remove responsibility for project certification".
Latitude 63 said it continued to "fulfil its remaining obligations within the revised scope of work", but was ultimately also removed from Project Caymus by Crowley.
Crowley said it was "continuing to work closely with the Northern Territory government to ensure the … facility is constructed in compliance with all relevant safety, construction and environmental standards".
"Throughout the design and construction process, Crowley has confirmed that all required approvals will be obtained from the Northern Territory government and other relevant authorities prior to the start of operations," its statement said.
The NT Department of Lands, Planning and the Environment said it was "working with Crowley for it to provide independent verification of the required safety, construction, and environmental standards and considerations".
"This independent evidence is necessary to determine that the tanks meet Australian standards that will ensure the project can be completed and operated," the department said in a statement.
The NT government has never taken action against Crowley for starting and continuing construction at Project Caymus without a building permit.