A 31-year-old Fredericksburg, Va., man was seriously injured yesterday when a load of lumber slipped from a crane at the site of the $18.7 million Fairfax County Courthouse under construction in Fairfax City.

Louis T. Boggs, general foreman for Equitable Construction Co. Inc., the contractor, suffered multiple injuries, including fractures, according to a Farifax fire and rescue spokeswoman. Boggs was in the intensive care unit at Commonwealth Doctors Hospital.

According to the spokeswoman, one of the cables holding the stack of decking came loose as the load was about two stories above the ground. Boggs and two other men ran for safety, she said, but the load struck Boggs before he could escape.

According to an inspector with the Virginia occupational safety office, "Everything as far as we could see was properly attached."

Enforcement of safety standards at Fairfax construction sites has been under attack by county officials, who say the state needs more inspectors.

The county has decided to sue both the state and federal government in an effort to get more inspectors and more effective enforcement.

Recently a task force of federal inspectors, called in because of the high numer of construction-related deaths, swept through several Northern Virginia sites and issued citations for nearly 200 alleged safety violations.

There was no pattern of complaints at Equitable's courthouse construction site, a federal safety official said.