If the failure of competent persons to attend and be examined or the
prevalence of contagious disease or other sufficient cause shall make it
impracticable to supply in due season for any appointment the names of
persons who have passed a competitive examination, the appointment may
be made of a person who has passed a noncompetitive examination, which
examination the Commission may provide for; but its next report shall
give the reason for such resort to noncompetitive examination.