A 48-year-old man died of a heart attack suffered while reenacting a Union attack during the weekend's commemoration of the 135th anniversary of the Battle of Antietam, and a woman suffered serious burns when photographic chemicals caused her costume to go up in flames.

Organizers expressed regret today about the incidents but said they did not prevent most participants from enjoying the three-day event south of here.

"We're subdued by it," Don Warlick, site manager for the commemoration, said of the death Sunday of Timothy Landacre, of Bridgeport, W.Va. "We always hate to lose one. But talking to a lot of the reenactors, they felt like it sure was a nice way to go."

With about 15,000 volunteers dressed in period clothing, the re-creation of the single deadliest day in American military history was one of the largest Civil War reenactments ever held. Some 70,000 spectators attended the event, organizers said, enjoying the pleasant weather, the replication of Civil War-era life and the battle scenes. About 23,000 Americans were killed or wounded at Antietam on Sept. 17,1862.

But there was regret about Landacre's death, as well as the freak accident several hours later that left Elizabeth Gordon, wife of a photographer reenactor, with burns over 18 percent of her body.

"You can't mitigate the impact of losing someone to a heart attack or having someone on fire," said Susan Saum-Wicklen, treasurer of the Association for the Preservation of Civil War Sites and a member of the Hagerstown City Council.

"Those of us involved were clearly unnerved by it, but we dealt with it," she said.

Anthony Miller, a Confederate soldier reenactor from Senoia, Ga., was on the field when Landacre went down. "He was doing something he was enjoying," Miller said, adding, "I can think of worse ways to go, like sitting at home or mowing your lawn."

Medical personnel treated more than 300 people during the event, including several having seizures and many others suffering from heat exhaustion, sprains and lacerations. Organizers said the number of incidents was not unusual given the size of the event.

Emergency officials said Landacre suffered a heart attack during a reenactment of the famous Union attack through "the Cornfield" at dawn on Sept. 17, 1862. He started experiencing difficulty shortly after the reenactment began about 6 a.m.

"He told his unit he was feeling bad and started walking off the field and then collapsed," Warlick said.

"An officer on a horse rode out and called a cease-fire," Miller said. "They pulled {Landacre} off pretty quickly. Once they got him off the field and en route, then they started back up."

Emergency workers quickly administered cardiopulmonary resuscitation and advanced life support to Landacre, who was in cardiac arrest, said Doug DeHaven, deputy fire chief of the Halfway Volunteer Fire Co. Landacre was pronounced dead a short time later at Washington County Hospital.

Landacre's 13-year-old son had come with him for the reenactment, officials said. About half of Landacre's regiment did not want to continue after the incident and instead packed up to go home, taking the boy with them.

"His close friends left," Warlick said. "They felt like they couldn't go on."

The photography accident with Gibson, a resident of Rochester, N.Y., occurred about 11 a.m. in a tent where she was working with her husband, Rob Gibson. Officials believe that the Civil War-era chemicals used by the couple to give the photographs an authentic look soaked into her clothing and somehow ignited.

In front of horrified onlookers, Gibson fell to the ground and began rolling, extinguishing the flames. A reenactor standing nearby who works in real life as a nurse for a burn unit was able to begin treatment, officials said. Gibson was flown to Washington Hospital Center, where she is in stable condition. CAPTION: Union troops tend to their wounded during a reenactment of the Battle of Antietam by about 15,000 volunteers near Hagerstown, Md.