In recognition of those who rendered aid at the Jan. 8 Tucson shooting scene, the American Red Cross will host free CPR and first-aid training in 100 communities across the U.S. on March 19.

The Red Cross is calling the event "Save-a-Life Saturday."

Red Cross officials say many of the bystanders at the scene knew CPR and first aid, which helped to save the lives of those injured. Among those bystanders was Daniel Hernandez, an intern for U.S. Rep. Gabrielle Giffords. Hernandez helped mitigate the effects of the congresswoman's injury after she was shot in the head and has been credited with saving her life.

Six locations in Southern Arizona, including two in Tucson, will be part of "Save-a-Life Saturday." The other Southern Arizona locations are in Green Valley, Nogales, Sierra Vista and Douglas.

The training, expected to last 45 to 60 minutes, will include instruction in hands-only CPR, controlling external bleeding and managing shock. There will be sessions at 9 and 11 a.m., and one location will also offer a 1 p.m. class.

The cost of the training is being underwritten by Safeway and Walgreens. Giffords was standing in front of a Safeway when she was shot. The store is next to a Walgreens, and employees of both stores helped in the aftermath of the massacre, which killed six people and injured 13.

"As this tragic event unfolded, several bystanders knew these vital skills, which helped save the lives of many victims, including Congresswoman Giffords. This inspired us to offer these trainings right here in our community," Richard White, executive director of the Southern Arizona Red Cross, said in a news release.

A 2010 Red Cross survey showed that one in four people have found themselves in a situation where someone needed CPR. Recent research also shows that if more people learned hands-only CPR, it would increase the likelihood of people's surviving cardiac emergencies.

"Congresswoman Giffords is alive today in part because a heroic individual was trained in basic first-aid skills," Pia Carusone, the congresswoman's chief of staff, said in a prepared statement. "Training every American in these critical skills is one of the ways that we can ensure that good can come from the horrific events of Jan. 8. You never know when you, too, might be in a position to save a life.

"We are very appreciative of the Red Cross for putting on this inspired event in locations around the country, and we encourage every American to get trained on March 19."