Last month, officials at San Francisco International Airport hired a herd of part-time employees to toil on the west side of the property and engage in an unusual - but environmentally friendly - form of fire prevention.

Anyone looking down from a plane departing the airport may have wondered, What's with the goats?

For two weeks in June, Mr. Fuzzy, Cookie, Mable, Alice and nearly 400 other goats chomped on the brush in a remote corner of the airport. The area needs to be cleared each spring to protect nearby homes from potential fires. But machines or humans can't be used because two endangered species - the San Francisco garter snake and the California red-legged frog - live there.

It's not exactly the type of job you advertise in the local classifieds. So, for the past five years officials have turned to Goats R Us, a small brush-removal company run by Terri Oyarzun, her husband Egon and their son Zephyr.

The airport paid $14,900 for the service this year.

The goats travel 30 miles each spring from their home in Orinda, Calif., to the airport in a 16-wheel truck that Oyarzun calls her "livestock limo." They come with a goat herder and a Border Collie named Toddy Lynn. The goats spend two weeks cutting away a 20-foot firebreak on the west side of the airport.

"When passengers take off and fly over the goats, I'm sure that's a thrill," Oyarzun says.

Whatever the emotion, it isn't reserved for air travelers. When Oyarzun's goats aren't clearing brush at the airport, they're munching away on the side of California's freeways, at state parks, under long-distance electric lines and anywhere else with overgrown vegetation. The family has about 4,000 total active goats on its payroll.

Working at an airport does come with its own set of challenges, namely loud, frightening jets constantly taking off.

"There was an adjustment period," Oyarzun said. "But they have a lot of confidence in their herder."

The goats did their job. "We're pleased with our organic process for weed abatement," said airport spokesman Doug Yakel.

At least one other airport has taken note. Chicago's O'Hare International Airport has requested bids for goats to clear brush in an out of the way area of the airport's 7,000-acre property and expects them to be at the airport sometime this summer.

When goats become too old to work, they are typically sold for meat. But fear not, Mr. Fuzzy, Cookie, Mable, Alice won't end up at the slaughterhouse. The Oyarzun family lets its goats peacefully retire at its farm.

At least one part of air travel is still humane.