A good place to start is the National Fire Protection Association which has many Codes and Standards associated with explosion safety. I do not recall the NFPA Code, but some reading may help locate resources of value. The second resource is the National Electrical Manufacturers Association which provides standards for exposion proofing electrical equipment. This standard will provide information of use both in buying equipment and in retrofitting existing equipment. You should not swap any line in an explosives area and other actions may be needed.
Sparks caused by static electricity, clothing and shoes etc are a danger, are an example.
Flamable vapors can be a significant hazard and should be treated with respect. I do not recall the NFPA Code, but some reading may help locate resources of value. This standard will provide information of use both in buying equipment and in retrofitting existing equipment. Please click the button only once.