A safety procedure or safety precaution was a safety protocol used in order to complete a task with minimal risk of injury to the one performing it or damage to the equipment used.
In 2293, Spock attributed an explosion on Praxis to over-mining and failure to take enough safety precautions. (Star Trek VI: The Undiscovered Country)
In 2364, Jean-Luc Picard explained his order to lock phasers on the Bandi ship as being a routine safety precaution. (TNG: "Encounter at Farpoint")
In 2368, Picard explained to Timothy that the computer onboard the SS Vico had safety precautions, meaning nothing he touched could have been responsible for the starship's destruction. (TNG: "Hero Worship")
In 2369, William T. Riker ordered all necessary safety precautions to be taken while simulating the explosion on the USS Yosemite. (TNG: "Realm Of Fear")
Also, that year, Doctor Julian Bashir reminded an injured Jones to lift with his back straight and use an anti-gravity generator next time. (DS9: "The Passenger")
In 2374, Harry Kim cautioned Seven of Nine against touching an electrical cable with her bare hands, despite her assurances that her exoskeleton could take the charge. He reminded her that she had to follow safety procedures, which she dismissed as a waste of time. Kim then reminded her that she'd been assigned to work with him and ordered her to follow the rules, which she agreed to do. (VOY: "Revulsion")
In 2375, Kathryn Janeway had the replicator in Kashyk's quarters aboard USS Voyager taken offline as a safety precaution against him replicating a weapon. (VOY: "Counterpoint")
In 2378, Kleg decided to begin Tom Paris's flight safety course with a review of safety procedures. (VOY: "Natural Law")