Two people are being remembered and an investigation continues into the explosion that took their lives. April Roper, a homeowner, and Larry Radford, a Questar Gas employee, were killed Tuesday afternoon in a natural gas explosion in Roper's new Saratoga Springs home.

Questar spokesman Darren Shepherd said investigators are trying to determine how natural gas from an outdoor leak migrated into the house and what caused it to ignite. Evidence is being sent away for analysis and the results might take weeks or months.

"It could be some time," Shepherd said.

Police say the explosion happened after work crews punctured a natural gas line in the Sunrise Meadows neighborhood near the home around 1:30 p.m. Tuesday. Questar employees repaired the 2-inch plastic gas line that serves the neighborhood and then evacuated nearby homes while searching for gas.

At about 4 p.m., after gas had been shut off to the home for about 25 minutes, April Roper and Radford went into the basement of the home to turn on the water heater and furnace.

Also at the home at that time were Roper's husband, Greg, and their 16-month-old daughter, Olivia, neighbor Kris Ewert, and her infant son, Ashton.

The two women were preparing for an afternoon walk with their children when April Roper went back inside with Radford.

Mere minutes later the house exploded.

"The kids were in their strollers and we stopped to let the Questar guy in and that is when the house exploded," Ewert said. "I took care of the kids. I covered Ashton with my body and when I got up to look for Olivia her stroller was behind me a few feet and upside down. I got her out and she was fine."

Shepherd urges everyone to be familiar with the smell of butyl-mercaptan, a strong-smelling chemical that is added to natural gas so people can detect gas leaks.

Questar offers brochures that have a scratch-and-sniff panel that gives off butyl-mercaptan's pungent odor.

"It's very unpleasant and when you smell it you know that something's wrong, and that's the time to get out of the building and make the call to Questar from a safe location," Shepherd said.

If you smell a natural gas leak, Questar urges the following safety measures:

Do not light a flame.

Do not use the telephone, turn on light switches or use any electronic devices. They can ignite the gas.

Do not start a motor vehicle.

Evacuate the building immediately and get a safe distance away, then call the gas company.

More natural gas safety information is available at www.questargas.com.

This story appeared in The Daily Herald on page A1.