The briefing at the San Diego Fire Department last week turned from the routine to the unthinkable: Africanized honey bee. Killer bees.

And even these hardened veterans of crisis and fear couldn't contain their anxiety.

"Jesus Christ," one old-timer muttered as he contemplated the kinds of rescue missions his men may be called upon to perform, tactics not found in existing training manuals.

Fire Capt. Jeff Carle went through his color slides and showed the video from Texas where the bees already have claimed a third of the Lone Star state.

Carle talked of how thousands of agitated bees will attack a single target in defense of their hive, and how firefighters in full gear--with duct tape closing openings to their skin--will pull victims to safety.

Another fireman sighed a vulgarity, and a vial containing two Africanized honey bees was passed from one to another for close inspection.

Slow but unstoppable, the front is moving toward California's second-largest city, their first metropolitan stop in the state.

The bees heading this way now are in the Mexican state of Sonora, 170 miles south of the U.S. border. Given their 300-mile-a-year flight, they'll be in Tucson by next year. Experts figure one flank will veer west and follow the Gila River to the Colorado River near Yuma. Then they'll spread north and west again, swarming across Imperial County, from one irrigation canal to the next, and claim San Diego County as theirs.

And it will happen by sometime in 1994, if not sooner.

Within six months of their arrival in San Diego, authorities worry, 10 million people in Southern California will be exposed to the ravages of the Africanized honey bee, this hyperactive misfit that mistakenly was let loose by a Brazilian beekeeper in 1957. It has wrought damage and hundreds of deaths along its path ever since, multiplying from the initial 26 renegade swarms to more than 2 million colonies today.

Now all those wisecracks about killer bees in South America, those visions of B-grade Hollywood horror films, are evolving into serious government talk about how to prepare for the bees when they enter Southern California.

State officials say San Diego County is, for good reason, leading the preparations.

* Kathleen Thuner, San Diego County's agricultural commissioner, went to Washington on Friday as California's task force representative to meet with federal officials for an update on the bees and to try to wrest money to deal with the problem here.