The Transportation Security Administration (TSA) on Tuesday handed down another set of directives aimed at protecting critical pipelines that transport hazardous liquids and natural gas against cyber attacks.

The second security directive, issued two months after the initial orders were put out, requires owners and operators of TSA-designated critical pipelines to implement specific mitigation measures to protect against ransomware attacks and other known threats to information technology and operational technology systems. It also requires these pipelines to develop and implement a cybersecurity contingency and recovery plan, as well as conduct a cybersecurity architecture design review.

The Department of Homeland Security’s (DHS) Cybersecurity and Infrastructure Security...