Any salaried employee of an oil facility in ISIL-held territory in Iraq and Syria could be considered a “legitimate target” for coalition airstrikes, U.S. officials have revealed, spurring both human rights and strategic concerns about the increasingly blurry line between enemy combatant and coerced civilian in the campaign to stamp out the armed group.

The revelation was noted in a New York Times article published Tuesday about a Delta Force commando raid in eastern Syria last month that obtained an apparent treasure trove of laptops and cell phones belonging to members of the Islamic State in Syria and the Levant, or ISIL. Among the several terabytes of data harvested from those devices were details about the staffing and operation of the group’s lucrative oil facilities across Syria and Iraq that reportedly dispelled widely held assumptions that it was mainly “conscripted locals” operating these refineries. Rather, they are now believed to be “salaried Islamic State employees, thus making them legitimate targets” for military strikes.

An official with CENTCOM, which is leading the aerial campaign against ISIL in Syria and Iraq, did not provide further clarification of this designation in an email to Al Jazeera. In all its strikes, CENTCOM takes “great care – from analysis of available intelligence to selection of the appropriate weapon to meet mission requirements – in order to minimize the risk of collateral damage, particularly any potential harm to non-combatants,” the official said.

But the suggestion related by the officials who spoke to the Times – that receiving a salary from ISIL coffers transformed a worker into a “legitimate target” – appeared to dramatically expand the range of potential targets for coalition strikes. Though there is limited publicly available information about how ISIL runs its oil refineries, it is widely believed that most workers “were there before IS took over and are now coerced to stay on,” said Richard Mallinson, an analyst on oil markets for Energy Aspects, using another acronym for ISIL. Many chose to remain out of fear of retribution if they tried to flee, or because they simply needed the income to survive, analysts assumed.

“It’s certainly problematic from a human rights perspective if they're describing these people as legitimate targets,” said Matthew Henman, head of London-based consultancy IHS Jane’s Terrorism and Insurgency Centre. “There’s a massive distinction between those who support IS because they have no other choice and those who endorse its ideology, the card-carrying members of the group.”

ISIL has made a point of paying as many workers as possible in the critical service industries across its territory, including doctors and nurses in its hospitals and teachers at its schools. The strategy is part of the group’s efforts to appease its conquered populace and prove that its self-described “caliphate” is in fact a fully functioning state.

But it has made particular efforts to ensure that individuals with much-needed technical expertise to keep oil refineries running are convinced to remain when the group conquers an area, Henman said. Smuggling oil, mostly by way of Turkey, is a primary source of revenue for ISIL, with the group's black market oil exports reaching up to 80,000 barrels a day – a gain of over $1 million per day – at its peak last summer.

In that regard, months of coalition strikes on oil infrastructure appear to have taken a toll, Pentagon officials have said. But they may continue to be strategically risky. As the civilian death toll slowly creeps higher, military analysts warn that ISIL, which surged across Sunni lands by exploiting sectarian resentments of those states’ central governments, will be keen to explain a mounting civilian death toll from the strikes as evidence that the U.S. and its allies are waging a war on the Sunni people, and that ISIL is the only force who could defend them.

If the non-combatants who staff oil facilities are considered fair game, analysts note, that could be counterproductive towards the coalition's goal of prying the local populace away from ISIL. "If these lines and boundaries start to blur," said Henman, "you'll have a population caught between ISIL forces on the ground and coalition forces in the sky."