The hand grenade is getting its first upgrade in more than 40 years. Army engineers at Picatinny Arsenal, N.J., are developing a multi-purpose grenade, capable of providing both fragmentation and blast overpressure. The new grenade also will be safer and more effective than its predecessor, the Army stated. Troops also will see the return of concussion-grenade capability, which disappeared when those were taken out of service in 1975 because of asbestos concerns. The new grenade also will be designed for ambidextrous use.