Four flags entered the parade grounds at the Umatilla Chemical Depot on Tuesday morning. Three left, signaling the end of military control of the installation, 71 years after its inception.

About 400 people attended the Operation Lights Out event Tuesday, a ceremony that marked the deactivation of the base and saw Lt. Col. Kris Perkins, Depot Commander, relinquish command.

The Umatilla Army Ordnance Depot opened Oct. 14, 1941, less than two weeks before the first munitions shipments arrived by rail for storage in the Depots igloos low, dirt-covered storage structures. Six weeks later, after the attack on Pearl Harbor, Depot workers shifted positions to support the United States entry into World War II.

The first chemical weapons arrived in 1962, and in the early 1990s, the site grew to include the Umatilla Chemical Agent Disposal Facility, where 12 percent of the nations chemical weapons were safely destroyed by Oct. 25, 2011, when the final container that once held mustard agent exited the facility.

Umatilla Chemical Depot has been home to some of the most skilled, hard-working and dedicated men and women our national has ever produced, said Don Barclay, acting director of the U.S. Army Chemical Materials Agency. The men and women of Team Umatilla have left a lasting legacy of hope for this generation and future generations.

Barclay, along with Perkins and Sgt. 1st Class Damon Pannell, completed the casing of the colors ceremony, a military procedure involving the covering of an organizational flag and symbolizing the end of military operations for the site.

Military units are given flags with color arrangements and symbols unique to that unit. When a change of leadership takes place, the flag is passed to the individual assuming command, according to Hal McCune, historian and protocol manager for the UMCDF.

Todays ceremony is not about the assumption of command, but the relinquishing of command by the 35th and final Umatilla Depot Commander, Lt. Col. Kris Perkins, and the deactivation of a unit with an illustrious history spanning 71 years, McCune said. Today, the Umatilla Chemical Depot will be officially deactivated and case its colors for the final time. When the colors depart the field this morning, it signifies that the Umatilla Chemical Depots mission is complete.

On Aug. 1, the property will be turned over to the Oregon Army National Guard, which has already established a training facility on the site.

The future of Umatilla looks as bright as its past, Perkins said. Its in good hands.

In his final remarks, Perkins said he became the former commander with pride and respect, not sadness or regret.

With its mission complete and its colors cased, Umatilla Chemical Depot takes its rightful place in the pages of history, Perkins said. Very few commanders get to furl the colors and utter the words mission complete It has been my duty, my privilege and my honor to see the Umatilla Chemical Depot to its successful end. May God bless each one of you here today, may God bless America … and mission complete.