The short answer is HELL NO. For emergency responders entering Immediately Dangerous to Life or Health (IDLH) atmospheres while wearing a Self-Contained Breathing Apparatus (SCBA), a Qualitative Fit Test (QLFT) is insufficient and not compliant with 1910.134 or 1910.120.
1910.134(f)(6) QLFT may only be used to fit test negative-pressure air-purifying respirators that must achieve a fit factor of 100 or less.