PLFaultCAT is a tool for software fault tree analysis (SFTA) during product-line engineering. When linked with DECIMAL, a product-line requirements verification tool, the enhanced version of PLFaultCAT provides traceability between productline requirements and SFTA hazards as well as semiautomated derivation of the SFTA for each new product-line system previously verified by DECIMAL. The combined tool reduces the effort needed to safely reuse requirements and customize the product-line SFTA as each new system is constructed.