Regarding the July 21 editorial “No answer at 911”:

We understand the fear and frustration of people who were unable to reach 911 after the June 29 derecho. We’re disappointed with our performance, and we have spent the past several weeks investigating what happened, why it happened and what needs to be done to prevent it from happening again.  

Our network is designed with multiple redundancies to be resilient in the face of power and other facility failures. Indeed, storm-related power failures affected more than 40 of our facilities, and our backup power kept the vast majority of them running. However, the derecho extensively damaged other facilities. This caused failures of critical network elements that route and complete 911 and other calls.

Our investigation has determined that the failure of one of two backup generators to start at each of our Arlington and Fairfax central offices was a primary contributor to the Northern Virginia disruptions. But these issues should not, in and of themselves, have caused the 911 problems. We’re inspecting other damaged equipment that may have contributed to the disruptions.

We immediately began correcting the issues we identified, and we’ve begun a region-wide review of the entire 911 design infrastructure to identify and protect against areas of vulnerability. We also understand the importance of communicating with 911 centers and the public during extraordinary events such as the derecho, and — while we did communicate with both — we can and will do better.

We have had productive meetings with several entities investigating the storm’s effects on 911 services. In the next week, we will begin to meet with public safety officials to share our findings about their specific 911 centers. We also will report our findings and corrective action plans to the investigating groups.

We failed to meet the expectations of the region’s residents and public safety community after the derecho. This is unacceptable. We know that the quality and reliability of all the services we deliver are paramount. We will improve.

Anthony Lewis, Washington

The writer is Mid-Atlantic region vice president of Verizon Communications.