Which preposition to use with disregardant

of Occurrences 1%

In the work of their repatriation none will be more eager to help than the American missionaries, who, at the time of the last massacre, as so often before, showed themselves so nobly disregardant of all personal danger and risk in doing their utmost for their murdered flock, and who have explicitly declared their intention of resuming their work.

Which preposition to use with  disregardant