Generally it's better, on these forums, to state your problem in detail, along with your solution. There may be better ways to achieve your goals than what you perceive as "the" solution. There are a lot for really experienced people here who would welcome the challenge to help you. I don't think I can...but once the problem is out there...you will get solutions!
And an elaboration of your "hazadous enviroment" might help. You are aware that DC motors of the type you are describing produce arcs as commutator bars pass the brushes. If the environment precludes electricity because of possible electrical arcs, you will be introducing a hazard.
Ken