Ludolf Luehmann, an information technology manager for Shell, told the World Petroleum Conference in Qatar his company had sustained an increased number of attacks, motivated by both commercial and criminal intent, the BBC reported Monday.
Shell and others in the industry have experienced attacks that could have left physical machinery at serious risk, he said.
"If anybody gets into the area where you can control opening and closing of valves, or release valves, you can imagine what happens," Luehmann said.
"It will cost lives and it will cost production, it will cost money, cause fires and cause loss of containment, environmental damage -- huge, huge damage."
Dennis Painchaud, with the Canadian energy company Nexen, said targeted attacks form a "very significant risk to our business."
"Cybercrime is a huge issue," he said. "It's not restricted to one company or another -- it's really broad and it is ongoing."