What is wrong in this picture? There is a guy working on welding with any proper PPE. He is using a paper to protect his face from carbon monoxide exposure. Workers in certain occupations often have an elevated risk of carbon monoxide exposure, including welders, drivers, auto mechanics, firefighters, and dockworkers. We can’t see or smell carbon monoxide, it can be a particularly dangerous substance. Knowing what work areas or equipment could expose workers to carbon monoxide will help workers protect themselves from exposure and help employers implement necessary controls to create a safe work environment.