An operator discovers that a log has been cut from the hatch of a distribution system storage tank. Until the incident is confirmed, this security breach should be treated as what?

• A. A potential contamination threat
• B. A minor maintenance issue
• C. A routine security drill
• D. A mechanical failure

Answer: (A)

Any unauthorized access to a critical water system component, like the hatch of a storage tank, is treated as a potential contamination threat until the incident is confirmed safe. The act of cutting a log from the hatch signals possible tampering or contamination risk, so immediate protective steps are warranted to protect public health—securing the hatch, restricting access, inspecting for signs of tampering, and following the incident response procedures, including appropriate sampling if required. This isn’t a routine maintenance issue, a routine drill, or a mechanical failure, as those scenarios involve known, approved activities or equipment malfunctions rather than an unexplained security breach.