MINNESOTA SN - Bulletproof whiteboards are being introduced in some US schools in what is being seen as adding a last-resort layer of safety for teachers and students against shootings.

The schools include one where there was an attack a decade ago in which two students were killed.

The 18-by-20in (46-51cms) boards use a material apparently stronger than police-issue bulletproof vests and can be used as a shield in an emergency. Among the places where they are being installed is the Rocori School District in Minnesota which has acquired nearly 200 of them.

In 2003, a 15-year-old boy took a gun to the school and fatally shot 14-year-old Seth Bartell and 17-year-old Aaron Rollins. The gunman, who is serving a life sentence, was convinced by a teacher to put the gun down.

The board’s manufacturer, Maryland-based Hardwire, has been working on armour protection devices for military vehicles and personnel for years. It turned its attention to school security after the Connecticut elementary school shootings last December that killed 20 children and six teachers.

Company officials said the whiteboards are already in schools in North Dakota and Maryland, and are being rolled out in Pennsylvania and California. Police chief Phil Jones said Rocori schools were the first to use them in Minnesota. He claimed he test-fired several rounds at it and told Fox News: “We put this board to the test, and quite frankly, that was the day I became a believer.”

Mr Jones and Scott Staska, the Rocori superintendent, stress that the boards are a supplement to a broad plan that includes lockdown drills and school resource officers.

At least one security expert questioned whether the boards would be effective.

Bill Nesbitt, president of school security consulting firm Security Management Services International, was not familiar with the whiteboards. But he said his initial reaction was that they may provide a false sense of security. The prudent thing to do would be to retreat from danger rather than hide behind a whiteboard, he said. Rollins’ father, Tom Rollins, said he does not believe the whiteboards would have saved Aaron or Seth. But he said it is a good idea, adding that if the teen gunman had decided to keep shooting, such a board may have helped other students. “He still had seven more shells in his gun, so who knows what would’ve happened,” Mr Rollins said.