Not everyone can wear a half- or full-face respirator while working. There are several conditions spelled out in the OSHA standards where respirator masks either won't work, or put the wearer in danger. The most frequent impediment to having a mask fit and therefore work properly is facial hair. OSHA is very specific in the new (1998) guidelines. In section 29 CFR 1910.134(g), Use of Respirators, it states: "Facepiece seal protection. The employer shall not permit respirators with tight-fitting facepieces to be worn by employees who have: (A) Facial hair that comes between the sealing surface of the facepiece and the face or that interferes with valve function..." This includes not only beards and giant 70's-style side burns, but stubble that's long enough to get in the way of a proper fit. Another important consideration are corrective lenses. If you wear contact lenses, OSHA says you can wear a full-face mask or a half-face mask and chemical goggles. But for folks with traditional glasses, it has to be a full-face mask with the proper corrective glasses insert, since the arms of eyewear can get in the way of a proper fit on a half-face mask. We touched on another problem that occurs when wearing a respirator in a blog about breathing traffic exhaust. The heat generated by wearing a respirator can cause people with medical conditions such as eczema to have flare-ups. And it seems obvious, but still important to mention, that folks with breathing problems like asthma may have greater difficulty pulling air through the filters and cartridges while working, and therefore shouldn't handle jobs that require respirators. Other considerations mentioned in the OSHA report are for people with known heart issues, or who may experience claustrophobia. At the end of the day, it's the employers who are responsible for knowing the laws about what can and can't be worn by their employees. While employees must make supervisors aware if their ability to wear respirators changes, it's important that all of the people required to work with breathing protection be tested for proper fit, and abide by the rules that keep the equipment functioning properly. Stay safe. Work smart. Thanks for reading.