The hazard
Well sites put flammable gas and liquids, possible toxic gas like hydrogen sulfide, high pressure, heavy equipment and several crews in one small area. Conditions can change fast, and one missed step can lead to a fire, an explosion or a toxic release. Knowing the hazards and looking out for each other is how everyone gets home.
The action
Flammable gas and vapors can travel and find an ignition source, so follow the site rules for phones, lighters, vehicles and hot work permits. If something changes, like a new chemical, a pressure reading that looks wrong or a strange smell, stop and ask before you keep going. Your employer must give you information and training whenever a new chemical hazard you have not been trained about is introduced into your work area. (29 CFR 1910.1200(h)(1))
ASK THE CREW
Which chemicals are on this location, and where are their safety data sheets?
From the talk: Oil and gas well site safety. Read it in full, free, with the questions and the sign-in sheet.