THOUGH STATE AUTHORITIES in Virginia are still busily defending their safety inspection system at construction sites, members of Fairfax County's Board of Supervisors have struck a better agreement with federal authorities for detecting safety violations and enforcing changes. Given the inability of the state to inspect sites frequently enough (or in some instances, at all), the supervisors' move is an important attempt to crack down on unsafe job conditions in the county -- and state authorities should be the first to recognize this.

When newspaper reports pointed out that Northern Virginia's booming construction industry had gone virtually uninspected during peak building months in 1979, state officials explained that their division office for this area was short one inspector for the first eight months of the year. That's quite a dent -- when you're talking about a total force of three. And when there are 14 worker deaths in Northern Virginia in two years, any absence of inspectors should be cause for something more than a routine response from Richmond.

Under the county-federal agreement, subject to formal ratification by both parties, the federal Occupational Safety and Health Administration would help in training 131 county inspectors. When they spot what they consider safety hazards, they would ask employers to correct all apparent violations. If an employer refused to comply, an inspector would refer the matter to OSHA's Falls Church or District of Columbia office for enforcement.

New federal support for a bigger and better inspection system does not automatically mean a reduction in the number of accidents or deaths. Accidents will occur regardless of whether the inspectors come from local, state or federal offices. But increasing the frequency and enforcement of inspections -- instead of dredging up apologies for a state system that has made local officials both uneasy and angry -- surely makes sense if human lives means more than bureaucratic face-saving.