US special forces recently captured ISIS' top chemical weapons chief, Sleiman Daoud al-Afari, formerly of Saddam Hussein's now-dissolved Military Industrialization Authority.
Al-Afari is said to have provided information on ISIS' burgeoning chemical weapons program.
The Wednesday bombardment is the initial round of airstrikes aimed at diminishing the militant group's ability to use mustard agent.
Though ISIS is believed to have only limited stocks of mustard gas, Kurdish authorities have already reported being shelled with "poisonous substances" in Northern Iraq.
"There were poisonous substances in these shells. We don't know what," Kirkuk province governor Najmuddin Kareem told Reuters on visit to the village on Wednesday.
The presence of chemical weapons in the region is especially troubling as Iraqi Security Forces prepare for a ground offensive to retake Mosul, ISIS' stronghold in Iraq.
CNN said it was unclear if the strikes, conducted over the last several days, were successful.
US Army photo by Spc. William Marlow/Released
Iraqi soldiers assigned to the 71st Iraqi Army Brigade prepare to breach a door during protective mask training at Camp Taji, Iraq, Oct. 15, 2015.