The purpose of this guidance note is to raise awareness of the consequences of tubing, hoses and fittings failures, present potential root causes identified through this initiative, and share lessons learned from previous failures and proven mitigations to prevent reoccurrences of BOP system control tubing, hose, and fitting failures. The study assessed subsea BOP system control tubing, hose, and fitting failures identified during operation or while testing between wells. This study did not consider leaks on other BOP equipment, leaks during BOP assembly, or leaks during shipyard installation and commissioning phase.