School security and fire safety experts are questioning a nationwide push allowing schools to buy portable barricade devices in the event of an active shooter in a building.

Those opposed to the devices say they're complicated to install under stress and could lead to dangerous unintended consequences including blocking authorities from an attacker inside a classroom.

The National Association of State Fire Marshals says such devices run counter to recommendations made after the 2013 Sandy Hook shooting.

Arkansas, Kansas, Michigan, New Jersey and Ohio are among states that have updated their fire or building codes in recent years to allow the devices.

Daniel Hogan is co-founder of Arkansas-based Ulockit Security. He says schools today are dealing with "a different evil" that requires extra protection.