As wildfires grow in size and frequency, more resources are needed to keep them in check. But experts say a Trump administration directive halting the purchase of new drones jeopardizes the rise of cutting-edge technology, curtailing the ability to manage wildfires and potentially putting more lives in danger.

In October 2019, the US Department of the Interior grounded its fleet of more than 800 drones and put a freeze on buying new ones due to concerns of Chinese spying. Many of the devices were used in wildfire fighting and prevention, including starting prescribed burns, a key tool in controlling wildfire. The interior department carries out more than 10,000 drone flights a year on average, according to federal documents.

This year, a shortage of drones has made it more difficult to contain fires raging across the western United States, insiders at the interior department said in an internal memo obtained by the Financial Times.

As wildfires increase in size and number, the department’s fleet of drones must “expand to meet the demand of preventative measures mandated for the reduction of wildfire via vegetation reduction”, the leaked memo, written by members of the department’s Office of Aviation Services, said.

Some Chinese-made drones are still currently being used for both wildfire fighting and controlled burns under an exception – but the ban still prevented the department from purchasing 17 Ignis drones it had planned to add to its fleet in 2020, the memo revealed. Drone Amplified, the purveyor of Ignis drones, confirmed to the Guardian the office pulled out of its plan to purchase drones this year.

“We spent four years building out our program and then overnight the grounding of Chinese drones put our orders on hold,” said Simon Weibel, a sales representative at Drone Amplified. “It has set the program back substantially, just as the technology was starting to get traction.”

Because of that shortage, the department will have done 28% less controlled burning in 2020 than it would have, had it purchased the new devices as planned by the end of the year, according to the memo.

Limiting access to drones means more work must be carried out manually, potentially putting lives at risk, the memo adds: “Denying the acquisition of UAS [drone] aerial ignition devices directly transfers risk to firefighters who must use manned aircraft to complete these missions rather than a safer option utilizing UAS.”

“Drones are never going to replace firefighters, but it has been a particularly deadly year for fires and there are times when it is not necessary to expose pilots to situations that could be deadly when our drones could take over,” Weibel said.

Controlled burns, also known as prescribed burns, are increasingly being used to manage potential forest fires. In this practice, which was common in indigenous cultures before being made illegal, areas are burnt during cooler seasons to reduce the amount of vegetation and other fuel to prevent larger and hotter fires in the future. Drones have been leveraged for prescribed burns because of their relative safety and ability to fly in dark and smoky conditions.

Drones, and the wildfires they prevent, are just the latest issue to be affected by ongoing tension between the US and China. Relations have soured dramatically in recent months after Donald Trump banned products from the Chinese firm Huawei and threatened to ban China-based social media platforms, including TikTok and WeChat.

“Drones have gotten caught up in the cold war between the US and China, and it’s unfortunate,” said Chris Anderson, whose company 3DR supplied drones for the majority of flights carried out by the interior department in the past. 3DR is one of the firms the department will no longer purchase from because its drones contain parts made in China.

The January directive was part of a growing movement to decrease the use of Chinese drones for security reasons. In May 2019, the Department of Homeland Security warned against using Chinese-made drones and in September 2019, a bipartisan bill was introduced to bar federal agencies from buying Chinese-made drones.

A spokesman for the interior department said the department has conducted fuel management treatments, or controlled burns, on nearly 1m acres, putting it ahead of its yearly average. In 2019, it burned 1.2m acres in fuel management treatments. The spokesman said David Bernhardt, a former oil industry lobbyist and current secretary of the interior, is “committed to deploying all resources to protect human health and safety”.

“The secretary’s order grounding the department’s drones achieves these important objectives while addressing national security concerns that were raised in classified briefings late last year,” he said.

The interior department declined to comment on the report that it is set to complete 28% less of the controlled burning it planned to do in 2020. The spokesman added that the majority of prescribed burns are carried out without drones, and that 30,000 firefighters have been deployed across the US to fight wildfires. The Trump administration is currently assessing potential security threats in DOI drones, he said.