OSHA recently held a hearing on the proposed assigned protection factor table that would be added to the agency's respiratory protection standard. APFs are numerical ratings given to different types of respirators to tell users how much protection the respirator can provide. The higher the number, the greater the protection.

Of all the respirator categories that have been given assigned protection factors, the biggest controversy is whether an APF of 5 or 10 should be used for elastomeric and half-masks and for filtering facepieces and quarter masks.

The AFL-CIO supports an APF of 10 for elastomeric half-masks and an APF of 5 for filtering facepieces and quarter masks, contending the types of mask do not provide the same level of protection. Respirator manufacturers, represented at the hearing by the International Safety Equipment Association, support an APF of 10 for all half mask air purifying respirators.