"OSHA certified" is a bit of a misnomer. OSHA produces the standards which personal protective equipment must meet, but the organization doesn't certify equipment. The Allegro air line respiratory systems, for example, are made to fulfill safety requirements, and are useful against a range of workplace challenges. While you need equipment that meets the OSHA requirements for your specific work place challenge, you won't find anything that is actually OSHA certified or OSHA approved.
OSHA will make reference to certain standards, and say that a worker must use equipment that complies. Some, such as NIOSH respirator mask/cartridge approvals, are very specific. Others, like the ANSI standards, are more performance based. So, when you come across a certain respiratory hazard, we look to see what the applicable OSHA standard might be, and what type of gear to use.
In the case of an airline respirator, it might be that you are spraying urethane paint or insulating foam. A respirator system with a constant flow tight fitting mask will have to provide 4 - 6 cubic feet per minute of grade D breathing air. Using an Allegro 9200-01 system when encountering this type of challenge, would be OSHA compliant.
If you're unsure what the OSHA requirements for your work place hazards are, there is a fairly complete OSHA respiratory hazards information page you may find useful. Otherwise give our Customer Service folks a ring at 800-829-9580 for more help.