In a large publicity push to protect children, some of the nation’s largest insurers and other companies are mailing millions of pamphlets telling customers that children are safest in the back seat of cars with dual air bags.

Insurers are joining other companies and medical groups before the busy holiday traveling season to get a basic message out to their millions of customers: Air bag safety means “buckle up, with children in back.”

The mailing effort comes just two weeks after many domestic and foreign automakers announced they would send letters to millions of vehicle owners providing tips on how to protect children from deploying air bags.

Air bags have been blamed for the deaths of 30 children and infants, according to the National Highway Traffic Safety Administration.