Before being captured, Stephen McFaul, 36, an electrical engineer from Belfast, Northern Ireland, barricaded himself in a room with a colleague at the first sound of gunfire, quietly using his cellphone to assure his family that he was all right.

“I joked that I was from Northern Ireland and that I had been through better riots,” he told the colleague, according to John Morrissey, a representative for his family in Belfast who was responding to reporters for media organizations around the world.

Mr. McFaul, who had been sent to work in Algeria only three weeks ago, was seized a few hours later, Mr. Morrissey said, and ultimately placed in the last jeep of a five-jeep convoy that came under heavy air attack from Algerian forces.

The first four jeeps were destroyed, and when Mr. McFaul’s vehicle veered off the road, he and a fellow worker managed to climb out of the back window, which had been broken. Their hands had been tied, their mouths taped and they had been forced to wear vests loaded with explosives, Mr. Morrissey said.

The two made a run for it, reaching the security forces, who disarmed the explosives. The spokesman said Mr. McFaul was “bright and together and nervously excited” about returning home.

At least one American, identified by a Corpus Christi, Tex., television station as Mark Cobb, also escaped. Mr. Cobb, who is from the Corpus Christi area, is said to have taken cover in an unused room and then made his way out of the plant unharmed, according to the station, KRIS-TV. On Friday, the station said, Mr. Cobb sent a text message to a friend that said, “I’m alive.”

Other foreigners, like Alexandre Berceaux, a French employee of a catering company working at the site, hid themselves as best they could.