evidence: If available and used correctly, a respirator can selectively reduce the exposure you might otherwise receive. Respirators have been used for many years in the workplace, where employers have programs to make sure the proper masks are selected and that the respirator fits. When consumers use respirators, they don’t have such support, so this fact sheet includes lots of background information to help consumers understand the limitations and cautions that need to be considered. The goal is to avoid unintended problems that might occur through lack of understanding or a false sense of security. [...] The cautions, limitations and restriction of use provided with the respirator must be strictly followed. If your mask does not make a tight seal all the way around your face when you inhale, you may breathe contaminated air that leaks around the edges of the face seal. Anything that prevents the face mask from fitting tightly against your face, such as a beard or long sideburns, may cause leakage. Some respirators come in different styles and sizes, and fit different people differently because people’s faces have different shapes. You also need training to know how to correctly put the mask on and wear it correctly. This information should be provided by the supplier of the respirator. [...] Gas Masks do not provide oxygen. If used in an environment with low oxygen levels, such as a fire, you are in danger of suffocation.