Federal labor officials want construction companies in New Jersey to ensure that employees working above 6 feet have the proper equipment to protect themselves from falls.

The U.S. Department of Labor's Occupational Safety and Health Administration issued the call Monday.

It's investigating four recent accidents in northern Jersey, including one where a worker fell through a roof into a vat of acid in Clifton, and another where a worker fell from the roof of a residential construction site in Bayonne.

OSHA is also probing a fall by a worker installing a steel frame in Madison, and another where a worker fell from an aerial lift in Secaucus.

In 2010, more than 10,000 U.S. construction workers were injured in falls while working from heights, and more than 250 were killed.

(Copyright 2012 by The Associated Press.  All Rights Reserved.)