ray barkley: our whole job here is to try and make the job safe or the place of employment safe. to avoid liabilities, industries with potential workplace hazards will often hire medical personnel and industrial hygienists to monitor employee health and safety. teresa howe: we fabricate a number of parts for the various launch vehicles here, so, employees could be exposed to a number of different chemical substances, fibers, vapors, gases, various liquids, corrosive-type materials. tracy schile: the goal of the industrial hygienist is to undertake preventive measures that keep our workers from being exposed to chemical, physical, and biological hazards. okay, so the time i started you is 10:05. and then this is to get the short-term exposure limit, so i'm gonna wave at u to get you to stop what you're doing. at 15 minutes, i'm gonna change out that cassette. okay. tracy schilf: we're looking for the results of what the fume exposure is gonna be for his welding process. he's using a... what's called the "rod 4-10," a stainless steel rod, it has some chromium in it, so that's what'