Tom Zarlingo doesn't see any contradiction between delivering babies and displaying fireworks. Obstetrician, pyrotechnician -- neither "is for people who panic," he said.

While many of his colleagues spend their free time playing golf, the 34-year-old doctor spends his lofting phosphorous-filled rockets hundreds of feet in the air, illuminating the sky at fireworks displays across the country.

Tonight, an estimated half-million people will witness his work at the annual Independence Day celebration on the Mall.

A specialist in high-risk obstetrics at Case Western Reserve University in Cleveland, Zarlingo also happens to be the chief designer of tonight's 35-minute show staged by the Vitale Fireworks Display Co. of Newcastle, Pa.

The unusual juxtaposition of interests is "not as strange as you might think," said Zarlingo, who also has been a professional photographer and musician. "I think it has to do with the excitement of the professions."

He admits to liking "a little danger," which the fireworks industry offers in ample supply. "I've had friends killed," he said.

During a show in Pennsylvania last week, a six-inch shell exploded on the ground while Zarlingo was standing nearby. He brushed his hair off his forehead to reveal a wound. "Sixteen stitches," he said. "First time in 18 years I've spilled any blood."

Zarlingo fell in love with the business as a teen-ager in Youngstown, Ohio, when he was hired to help with fireworks at a local carnival. He's been blowing things up ever since.

Mostly on his vacation time, Zarlingo stages about 12 shows a year for several different fireworks companies. A bachelor who says he's too busy to marry, he does the choreography at home on nights when he isn't on call at the hospital. In addition to medical journals, he subscribes to magazines such as American Fireworks News and the American Pyrotechnics Association Bulletin.

For 35 minutes of sound and fury tonight, the government has paid $95,000.

Since Tuesday, the doctor and his crew -- the men call him "Doc," a nickname he hates -- have been hard at work in a fenced-off area just east of the Reflecting Pool. They are creating a garden of cardboard and steel tubes from which they will launch more than 4,500 shells.

The rockets will be connected to five electronic control panels with 26 miles of wire. All together, the materials for the show are enough to fill three tractor-trailers.

Zarlingo is careful to make sure that the numbered tubes correspond to his diagrams, and that they are pointing straight up.

The fire department will inspect his handiwork before the show, lest some errant skyrocket go streaking across the Tidal Basin and make a house call at the Jefferson Memorial. "With the monuments and stuff down here, they're very careful," he said.

Zarlingo promises something worthy of the nation's capital on Independence Day, noting that this is "the status show" of the fireworks industry. "Most people who watch this will never have seen a show like this before," he said.

Some of the rockets supplied by Vitale, which staged last year's display, weigh as much as 25 pounds.

As much as the danger, Zarlingo said he thrives on the "creative aspects" of pyrotechnics. Few artists can command such a large audience for one performance, he said. "I don't think you can do anything else that entertains as many people at once."

As the hour draws nigh, Zarlingo has much on his mind. He must coordinate the start of the show with the end of a performance by the National Symphony Orchestra, which is playing on the West Lawn of the Capitol. Then he has to start the show's musical score precisely four seconds after the first shellburst.

Most of all, he worries about the weather. Rain can interfere with electrical connections, rendering some shells useless and causing others to explode on the ground. Either can spoil a show.

"I hope it doesn't rain," he said, looking at the sky.