The phrase “shelter in place” has been used at least twice in the last few hours. The first was in reference to a shooting at Fort Hood. “The incident began shortly after 5 p.m., when Ft. Hood tweeted and broadcast an alarm that all personnel should take shelter in place” The second was to do with Kent State. “Kent State campus puts shelter in place after gunfire.”

What is “shelter in place”?

The phrase appears to have originated in connection with a hazardous environmental contamination. It was part of civil defense and disaster preparedness. The CDC says:

“Shelter-in-place” means to take immediate shelter where you are—at home, work, school, or in between. It may also mean “seal the room;” in other words, take steps to prevent outside air from coming in. This is because local authorities may instruct you to “shelter-in-place” if chemical or radiological contaminants are released into the environment. It is important to listen to TV or radio to understand whether the authorities wish you to merely remain indoors or to take additional steps to protect yourself and your family.

Homeland Security has a very similar definition: “Shelter-in-place means selecting a small, interior room, with no or few windows, and taking refuge there. It does not mean sealing off your entire home or office building. If you are told to shelter-in-place, follow the instructions provided in this Fact Sheet.”

Gradually the word has morphed to mean to hide somewhere in case a roving shooter guns you down. Wikipedia notes: “The phrase has also erroneously been used, instead of the more accurate lockdown, to describe precautions to be taken by the public when violence has occurred or might occur (particularly in shootings) in the area and the perpetrator is believed to still be in the area but not apprehended. The public in the area is advised to carry out all the same tasks as a typical shelter-in-place but without the key step of sealing the shelter up to prevent outside air from circulating indoors, in this scenario people are simply urged to lockdown – stay indoors and “close, lock and stay away from external doors and windows.”

There is some debate over whether going into lockdown does any good in the face of an armed gunman or team.  Some people think it’s useless.

School safety expert Ken Trump told ABC News that he thinks the Sandy Hook teachers did what they could to protect their students.

“It does sound as though the teachers did everything humanly possible, down to risking their lives, to protect the children in this Connecticut school,” Trump said.

The school’s principal and five other adults died in the Sandy Hook school shooting in Newtown, Conn.

“Teaching kids to lock down, securing your rooms, and, in some cases, teachers stepping forth to protect the children at the risk of their own lives, is something that we see occurring more and more over the years in school safety,” Trump said.

How effective were these tactics against Adam Lanza?  There’s a growing body of experience about what happens in when shooters invade schools and malls. The Mumbai attacks and the Westgate Shopping Mall attack in Kenya are valid data, so the question deserves an answer.

At around the time of the Mumbai attacks I received an email from a recently retired US Marine Captain who followed the attacks with great interest and who expressed a frustration at not being at the hotel when the attackers tried their stunts. He felt sure, he said, that he could have turned the tables on them somehow. But he mentioned something curious. “They used buddy pairs,” he wrote.