PITTSBURGH (AP) _ After an explosion seared his flesh, Thomas Tiernan thought his abdomen and left hand would bear the type of scar he had once seen on a burn victim.

``It was all stretched out and ugly looking,'' Tiernan said.

Instead, where he was burned, Tiernan has skin. It's splotchy and purple, but it's flexible and even has little hairs.

The doctoring of massive, severe burns has come a long way in the past 10 years, debunking accepted ideas and helping more burn patients survive with better health.

Two main factors account for the progress. In the worst cases, feeding tubes ensure that patients receive the extra calories and protein they need. And surgeons remove damaged skin quickly to start skin grafts, reducing deaths, disability, pain and the hospital bill.

Dr. Steven J. Gerndt, a surgeon at University of Michigan Hospitals, said that in the 1960s, a patient aged 10 to 40 with severe burns over half the body had a 40 percent to 50 percent chance of living. In the 1980s, the victim's chances were 70 percent. Today, they are 90 percent, although some sufferers are surviving only to endure severe disabilities.

In the ``old days,'' doctors waited for a burn victim's skin to slough off _ actually rot away _ before they stapled skin grafts on, said Dr. Harvey Slater, director of the Burn Trauma Center at West Penn Hospital in Pittsburgh.

``Nurses and doctors would come and pick at the dead skin every day,'' Slater said. The excruciatingly painful process could last up to three weeks _ a long, expensive hospital stay.

``The burn unit smelled terrible because all this skin was infected, and many of these people died,'' Slater said.

Now, a day or two after a severely burned patient arrives, surgeons shave away damaged skin and start the grafts. The new skin comes from elsewhere on the body, either transplanted directly or grown into larger pieces at a private laboratory in Boston. While the lab works, cadaver skin may protect the patient temporarily.

The quick grafts protect against infection _ the victim's worst enemy _ and reduce scarring. Many victims who would have been disfigured and disabled in 1980 look better and feel better in 1995.

Nevertheless, two major problems remain in burn therapy. Doctors still can do little to treat lungs damaged by smoke. And infection is a constant danger, causing 72 percent of all deaths among burn victims, according to Harry Gaynor, president of the National Burn Victim Foundation in Orange, N.J.

Whether 3-year-old Chelsea McCartney will be one of them isn't clear. Chelsea has had seven skin operations since March 13, when flames from a neighbor's burning house came through her bedroom window in her home in Ambridge, a Pittsburgh suburb.

Third-degree burns covered two-thirds of her body, and an anesthesiologist kept her in a coma for weeks to immobilize her.

When she woke up, she could not speak around the feeding tube in her throat, but after prompting, she gave her half-brother a special greeting.

``She stuck her tongue out, and she gave him raspberries, so she's there,'' said her mother, Pamela Camp.

Camp teases Chelsea that the feeding tube is giving her steak and potatoes. Nutritionally, that's an apt description. High-protein, high-calorie diets have become part of treating a burn victim, who needs the nutrients to fight infection and grow new tissue.

Ten years ago, sufferers with massive burns could starve to death in the hospital because the burns cause stomach troubles. Now, a feeding tube may deliver nutrients directly to the small intestine.

A healthy adult needs 1,500 to 2,000 calories per day. A burn victim uses about 2,500 to 3,000 calories.

``These patients may not be out of bed much. It's hard for them to believe their energy needs are actually higher,'' West Penn dietician Pamela Yurick said. To whet the appetites of patients who don't need feeding tubes, she stocks a refrigerator with ice cream and pudding.

Because smoke detectors are more popular and workplaces have been made safer, massive burns are less common these days.

Dr. Jeffrey Saffle of Salt Lake City, who directs the American Burn Association's national registry, said that in the 1960s, 20 percent of the patients admitted to burn units had burns over at least 60 percent of their body. Figures from the 1990s, to be published this month, show a decrease from 20 percent to 4 percent.

The nation maintains 1,809 beds at 138 burn units, Saffle said.

Peter Brigham, president of the Burn Foundation in Philadelphia, said the percentage of industrial workers among those massive-burn patients has fallen greatly, although apparently no statistics are kept.

``The massive industrial burn has largely vanished,'' Brigham said, probably because of safer workplaces and fewer industrial jobs.

Tiernan, whose burns from an explosion set off by a trashcan fire did not threaten his life, cleans his high-protein plate and keeps his elastic glove on so his skin heals smoothly. The pressure garment fools a body mechanism that makes collagen _ a protein _ and contributes to thick, stiff scarring. For reasons not yet understood, the body signals to burn wounds to keep making collagen long after it is needed.

Burned April 1, Tiernan already can touch his thumb to various points on his palm and probably will recover full use of his hand. His age, 32, is an advantage. Burns are riskier for the very young and the very old because their skin is thinner.

Of the two million people injured or killed by burns last year, one-third were 17 or younger, according to Shriners Burn Institute in Cincinnati.

The typical burned child comes from a single-parent home in the inner city or a rural area.

``It's a disease of poverty,'' Slater said.