Security forces repel attack, but new wellhead fires are emitting noxious smoke and choking civilians who had just begun to resettle.
Upcoming offensive could push IS out of Kirkuk province, further squeezing Mosul and reducing threats to northern oil infrastructure.
Assassination marks first killing of senior North Oil Company official since spate of murders last year.
After two battles with IS fighters near Chemchemal, security forces are racing to root out militants setting up insurgent cells within KRG-controlled territory.
The Bai Hassan south station is back online, but key infrastructure remains damaged and a well fire is still blazing after two IS attacks in July and early August.
IS militants leave behind dozens of dead civilians, a trashed refinery complex, and a town choked by oil fires.
Over two days of grinding battles, thousands of soldiers liberate a swath of Hamdaniya, highlighting the difficulty of making even incremental gains on the road to Mosul.
Far behind Kurdistan's front lines, a suspected IS sleeper cell bombed a wellhead and set IEDs along a pipeline, exploiting security gaps around Kirkuk energy infrastructure.
Scorched-earth tactics cause deadly environmental damage, highlight IS group's battlefield losses and failure to sustain oil-fueled state.
Militants invade a gas compressor station and major oil field in Kirkuk province, killing police and oil workers and blowing up a storage tank.
