In high-risk operations, the first plausible diagnosis can quickly become the only diagnosis. This article explores confirmation bias, diagnostic fixation, and premature closure in troubleshooting—and how teams can use disconfirming evidence, alternate hypotheses, diagnostic time-outs, and independent review to avoid dangerous misdiagnosis.

Under pressure, attention can narrow so sharply that people focus on one alarm, one task, or one explanation while missing the hazard developing beside it. This article explores cognitive tunneling in emergency response and how HSE teams can design procedures, alarms, drills, and decision support to widen situational awareness when it matters most.