Radioactive particles spewed from a pipe at a French nuclear reactor on Wednesday, slightly contaminating 100 employees, a spokeswoman for the national electric company said.
It was the fourth incident at a French nuclear site in recent weeks and the second in five days.
Caroline Muller, a spokeswoman for Electricite de France, said 100 EDF employees were "slightly contaminated" by radioactive particles that escaped from the pipe at a reactor complex in Tricastin, in southern France.
The incident occurred in reactor No. 4 at the facility, which had been shut down for refueling, she said.
The employees went home but will be tested, she said, insisting that the contamination was slight — a dose smaller than 1/40th of the regulation limit.
"What concerns us is less the level of the people contaminated than the number of people contaminated," Muller said by telephone.
Experts were studying what led to the incident, she said.
The incident came a day after authorities lifted a ban on fishing and water sports in two rivers that was imposed July 8 after liquid containing unenriched uranium leaked from a broken underground pipe at a site run by nuclear giant Areva at the huge Tricastin complex, near the city of Avignon.
Areva said Friday that liquid containing slightly enriched uranium leaked at another of its sites in southeast France. The same day, 15 EDF workers were exposed to what the company called non-harmful traces of radioactive elements at the Saint-Alban plant in the Alpine Isere region.
France is the most nuclear-dependent country in the world, with 59 reactors churning out nearly 80 percent of its electricity. After the first incident, the government ordered a check of groundwater around all nuclear sites in France.
The incidents have prompted questions about the state-run nuclear industry, at a time when eyes are turning to nuclear energy because of the soaring price of oil.