Guilty Plea in EPO Incident at Power Facility

A disgruntled sysadmin has plead guilty to pushing the Emergency Power Off button in a data center controlling the California power grid.

A disgruntled system administrator who intentionally pushed the Emergency Power Off button in a data center controlling the California power grid has plead guilty to a felony and will be sentenced in February. Lonnie Charles Denison admitted in U.S. District Court in Sacramento that he went into a room at the California Independent System Operator's data center in Folsom on April 15, broke a glass cover and pushed the EPO button, prosecutors said.

Denison, a computer specialist at Science Applications International Corp. (SAIC), was described by the FBI as having a "history of mental illness, drug abuse and alcohol issues." SAIC had warned several days before the incident that Denison should be denied access to the facility Cal-ISO facility. No blackout occurred, primarily because the incident happened on a Sunday during a period of light usage of the power grid. Denison was identified by surveillance-tape footage and his security-access code.


The EPO button (also known as the "Big Red Button") allows firemen to rapidly disconnect power controlled in the event of a fire, and quickly shut down the HVAC systems serving a data center. In non-emergency situations, it can be an accident waiting to happen. A surprising number of EPO activations are attributed to either sabotage or human error. While employee and contractor sabotage is difficult to predict, effective data center management can minimize the risk of EPO related outages. Read Averting Disaster with the EPO button for management tips.