Another mass shooting.

More workplace violence.

Senseless deaths — again.

All this in a place that brags about its “exceptionalism.”

The gunshots that left at least 13 dead, including a shooter, at the Washington Navy Yard are reminders that violence in America, rather than an exception, is all too common.

Many times the location has been on streets not too far from the Southeast D.C. facility. This time the killing field was a federal workplace, nondescriptly known as Building 197. It’s on a military installation that probably has more security than many other federal locations. It’s a place where many workers are trained to protect themselves and others.

But that didn’t stop a shooter from gunning down the innocent. Who knows why?

Whatever the reason, it’s another demonstration that even the safest places really aren’t safe. The degree of security visitors are subjected to in even low-level federal offices can be a time-consuming hassle, while giving those who work in those facilities greater security.

Monday morning’s shooting undermines that sense of security. It shows that vulnerabilities are real. It indicates that security might not be tight enough. Perhaps federal employees who now pass through security with the flash of a badge also should be scanned and their bags examined, just like guests.

No matter how tight the security at the Navy Yard, after Monday’s tragedy, “it’s not secure enough for me,” said Patricia Ward, a logistics management specialist there. “I’m terrified,” she told reporters. “I don’t even know if I want to come back into the building. I don’t feel safe.”

The Federal Protective Service is responsible for keeping many federal buildings safe, though not the Navy Yard. Unfortunately, the Government Accountability Office has released a series of reports that are critical of the FPS and that repeatedly “have shown gaps in the security status” of federal facilities, said Mark L. Goldstein, GAO’s director of physical infrastructure.

GAO has “a body of work that has shown deficiencies” in the training of FPS contract guards and in the backlog and quality of the risk assessments that FPS does for federal buildings, he said.

Make no mistake, federal workplaces generally are safe places. But the Navy Yard case joins a long list of violence at federal facilities or against federal employees. News researcher Alice Crites compiled these examples:

●Two CIA employees killed and three injured on Jan. 25, 1993, outside CIA headquarters in Langley.

●●Four people killed and 23 wounded in a June 21, 1994, shooting at Fairchild Air Force Base near Spokane, Wash.

●One hundred sixty-eight died in the April 19, 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City. More than 500 were injured. This was the second-deadliest terrorist attack on U.S. soil.

●Two U.S. Capitol Police officers, John Gibson and Jacob Chestnut, were killed by a gunman in the Capitol on July 24, 1998.

●Seven U.S. Postal Service employees were shot dead by a former colleague, who then took her own life, in a Goleta, Calif., postal sorting facility on Jan. 30, 2006.

●A soldier was killed by gunfire at the Army-Navy Career Center in Little Rock in June 2009.

●A security guard at the U.S. Holocaust Memorial Museum was killed that same month by a man described as a neo-Nazi white supremacist.

●Thirteen people were killed and 43 injured during the November 2009 mass shooting at Fort Hood, Tex.

●A security officer was killed and a deputy U.S. marshal wounded in a shotgun shooting at a federal courthouse in Las Vegas on Jan. 4, 2010.

●An Internal Revenue Service manager was killed in an apparent suicide attack Feb. 18, 2010, when a man flew a small plane into an Austin building that contained an IRS office. Thirteen people were injured.

●Two Pentagon officers were wounded during a gun battle with a man who died during the firefight in March 2010.

●A Border Patrol agent, Brian Terry, was killed in December 2010 near Nogales, Ariz.

●Six people died in the shooting that wounded former congresswoman Gabrielle Giffords (D-Ariz.) and 18 others during an outdoor gathering in Casas Adobes, Ariz., near Tucson.

Like others on this sad roll call, the Navy Yard shooting “targeted our military and civilian personnel. These are men and women who were going to work, doing their job, protecting all of us,” President Obama said Monday. “They’re patriots, and they know the dangers of serving abroad — but today, they faced unimaginable violence that they wouldn’t have expected here at home.”

Workers like Patricia Ward should not be afraid to go to work.

Twitter: @JoeDavidsonWP

Previous columns by Joe Davidson are available at wapo.st/JoeDavidson.