Some metals when struck against any surface, don't produce a spark "hot" enough to cause an explosion. At least that is what I read. An Aluminum switch or ring would produce a much hotter spark than say a stainless steel one. Stainless steel is possibly safer, depending on the characteristics of the hazardous material. I prefer a plastic switch since it is much more impact forgiving AND I would want a plastic hanger ring just to be on the safe side. I have never worked in those type of environments and as far as I can see, I probably never will. However, since I would like to consider myself to be more intelligent on flashlights than the average person, I would like to use that knowledge for the common good of anyone else. I would definitely want to protect our American workers who keep this country afloat the best I could, given the opportunity.
The Bright Star 2217 LED is all plastic on the outside, and no metal piece is exposed. The only real danger is from the optional S-biner that comes with it. It is mostly plastic, but has two metal latches. They appear to be stainless steal, which again produces a cold spark. It is the safest flashlight out there at the moment and the S-biner can easily be removed completely from the light itself. Much better to carry the light in your back pocket. Hope I have been helpful.