The 42-car Norfolk Southern Corp. train struck a parked locomotive and two cars at 2:39 a.m. Thursday in Graniteville. The noise stunned Ms. Pierpont, who had moved back to her hometown in August.
"The train sounded like it was going really fast," Ms. Pierpont said. "Then it was like a loud explosion - and then I heard a loud screeching noise."
She was one of many Graniteville residents who experienced exposure to the chlorine leak and reported to one of two decontamination centers at the University of South Carolina Aiken and Midland Valley High School.
Emergency officials confiscated residents' contaminated clothing, rinsed their skin and hair with water and treated them with oxygen.
"About 4:00, I finally looked outside my door to see what was happening, and the chlorine hit me so hard it took my breath away," she said. "I got two really big whiffs of it."
The thunderlike clap of the train wreck sent Jose Amaya lunging toward his front door.
But moments later, the Graniteville resident was diving back inside his Aiken Street home, overwhelmed by the odor of chlorine that filled the air.
"I opened my door and I saw smoke, like fog," he said. "I started to breathe something strong, and I almost fell. I took a cushion from the sofa and put it on my face. I tried to breathe through the cushion."
Marrell Dunbar didn't hear the crash beside the Avondale Mills Gregg Plant, where he was working the third shift, but he immediately felt the potentially toxic chlorine leak.
"I had eye irritation, chest pain and I was wheezing," he said. "You just saw the chlorine when it got in the air. It was a big green cloud. At one point, I passed out in the parking lot at work."
Nina Nindifer, spokeswoman for Aiken Technical College, heard the train wreck from her Graniteville home, about an eighth of a mile from the accident, and ventured to the accident scene later Thursday morning. She said the early morning crash sounded like a loud crunching sound.
"At 5 a.m., I started getting phone calls. I walked down and stood on the tracks and shot some photos," Ms. Nindifer said. "I saw train cars stacked on top of each other. It looked like pick-up sticks."
She said she saw plumes of smoke coming from one of the cars.
She washed off with cold water when she returned to her house and said she had only a slight burning sensation in her throat.
Juland Key wasn't aware of the dangers of chlorine exposure and ignored emergency officials' orders to steer clear of the contaminated area.
She spent several hours weaving in and out of back roads to bypass the road blocks barring access to Graniteville, desperate to check on her mother.
"My skin burned; it was itchy," she said. "I had been riding around for three hours on little roads (with the windows open) trying to get to her. That's where I guess I messed up."
Lester Ramsey also was oblivious of the chemical hazards that continue to threaten the railroad community.
The 88-year-old Graniteville resident set out for his daily morning walk only to be whisked away in an ambulance by emergency workers who noticed the elderly man walking along the road.
"If I knew this was going to happen, I would have stayed home," he said.
Derek Williams and his wife, three toddler children and nephew were evacuated from their Graniteville home that sits less than a mile from the crash site by emergency officials after he developed a headache and a tingling sensation in his arm.
"He was outside longer than anyone else trying to catch the dogs," said his wife, Candace Pitts.
Mr. Williams traded in his leather jacket and pants at the university's decontamination center for a white plastic jumpsuit.