There's something green at Olympia burger shack Big Tom - and it's not on the menu, which is bare of all vegetables save the humble potato and a few lonely burger toppings.

Instead, it's just about everywhere else. Owner Michael Fritsch has taken the classic drive-in and made it green, with features ranging from solar hot water to food waste recycling to a parking spot where customers can charge their electric cars.

Yes, people who drive Priuses really do eat burgers slathered in Goop, the secret special sauce. Or maybe they eat Boca patties slathered in Goop, which were added to the menu four or so years ago.

"We cook them in the fryers," Fritsch says. "French fries and onion rings go in the right side with the Bocas; dead animals go in the left side."

Heck, Fritsch is environmentally conscious, and he owns the place. He's also a vegetarian - except when he's in the Big Tom kitchen, where tasting the burgers is part of the job.

Why does a vegetarian own a burger spot?

He bought the place from his dad, Chuck Fritsch, who bought it in 1969.

"It's a comfort thing," Michael Fritsch says. "I grew up there. Dad was ready to retire. One day, I went in there and started working again, and I've been there ever since."

Maybe it's not as strange as it sounds. Fritsch is not a vegetarian for the usual reasons of health or ethics. He's a vegetarian because, well, because he likes to do the opposite of what his dad does.

"My father was on the Atkins diet back when that was a big thing," he says. "He was eating nothing but meat, and I stopped eating meat. It was just something stupid to do. ... It just stuck."

Try as he might to rebel, though, the tater tot didn't fall far from the fryer. "You grow up thinking, ‘I'm not going to be my parents,' " he says. "In some ways, you aren't, and in some ways, you are a mirror image of them."

Fritsch also got his environmentalism from his dad - sort of.

Chuck Fritsch converted his truck to run on the Big Tom's used cooking oil five years ago, and he put in the first solar hot water system on the roof in the '70s. (That system stopped working about 20 years ago, and the new one was installed last fall.)

It's always been a conversation piece: What can solar panels do in a climate with so little sunshine?

Six months of the year, the system does all the heating that's needed, Michael Fritsch said. And even on a gray winter day, it heats the water to 57 degrees, an energy-saving start.

But, Chuck Fritsch says, it wasn't environmental concern that prompted those pioneering choices.

"I'm a cheap bastard," he says. "Michael is the environmental conscience that I never had."

Some of the changes are really small: The same old toilet now has a dual-flush system. On the way is a new icemaker that will make ice on demand, saving the energy lost when ice melts before it can be used.

Outside there's a bike rack to encourage neighborhood customers not to drive. (Yes, it is a drive-in, but the carless are welcome, too, and there's a picnic area in the parking lot.)

If beef is not the most environmentally friendly of foods, Big Tom's beef is at least raised in the Northwest, and Michael Fritsch is talking to a supplier in Portland in an attempt to get a little more local.

And then there are those deep-fried Boca burgers. Big Tom's is listed in a guide for traveling vegetarians, many of whom hop off I-5 for a fast meal.

But green goes only so far.

Salads, for example. That would be going too far.

"People come to us for hamburgers," Chuck Fritsch says. "If they want vegetables, they'll go to a vegetable stand."