This incident is a PERFECT example of what can happen when STORED ENERGY is overlooked. For energy sources like hydraulics and pneumatic (e.g., gases), merely closing a valve and locking it closed or locking out a pump is NOT full energy control. Procedures MUST include the means to dissipate the stored energy to the Zero Energy State (ZES). Keeping in mind that sometimes the dissipation of this stored energy in and of itself can be a hazardous task and may require special PPE and procedures so as not to cause injury or create a hazard.