DETROIT (AP) — General Motors is recalling nearly 780,000 crossover SUVs mainly in North America because the rear power lift gates can suddenly fall and hit people.

The recall covers the Buick Enclave from the 2008 to 2012 model years and the Chevrolet Traverse from 2009 to 2012. Also affected are the GMC Acadia from 2007 to 2012 and Saturn Outlook from 2007 to 2010.

GM says in documents filed with U.S. safety regulators that dirt can get into the gas struts that hold up the gate, causing them to wear and fail. The company has 56 reports of injuries.

Dealers will replace faulty struts and update lift gate control motor software to prevent rapid closing.

GM says struts on SUVs built after March 1, 2012 were installed differently and are less vulnerable to dirt particles.