WHAT COULD have been a hideous disaster -- costing scores of lives and blowing a Fairfax County subdivision to bits -- didn't happen, and lots of good people helped keep it that way. Cool heads in the neighborhood, brave firefighters everywhere, and calm, efficient police officers in the sky with megaphoned evacuation warnings did a splendid job in a terrifying, tense situation last weekend: a bulldozer had torn open a 32-inch underground pipeline and triggered a 100-foot geyser of high-test unleaded gasoline that rained on everything from trees and roads to houses, cars and gardens in the Centreville subdivision of Singleton's Grove. In all, 47 families had to be evacuated.

With little or no time to plan any sophisticated rescue operation -- or prepare for such an enormous firefighting job, firemen moved into this huge vapor-filled area where even one small spark could have set off an explosion. Residents have had nothing but praise for the firefighters' work, which continued long after the immediate explosion threat. Throughout the weekend, firefighting crews dissipated fumes, mopped up puddles of gasoline, hauled away gas-soaked topsoil and escorted families into the homes, testing everything along the way and inside.

All in a day's work, to be sure; but that isn't your everyday kind of work, and Fairfax County residents can take much comfort and pride in the way their public servants reacted under extreme pressures.