Gas energy must be controlled via a mechanical energy isolating device that physically prevents the transmission or release of the gas. Gas energy lockout devices use positive means such as a lock and key to keep the associated energy isolation device in the safe position and prevent equipment energization. Depending upon the type of gas, some lockout devices automatically vent pressure when lockout occurs. Specific handling instructions may be required for some gases. Be aware of any special handling procedures or PPE that specific gases may require. Verifying the absence of gas energy after performing lockout/tagout can be done by attempting to operate the associated components and by observing the level indicators and/or associated gages to ensure they indicate 0 pressure.