Four Army Ranger instructors and 40 of their students have returned to duty after lightning struck near them while they were carrying out military exercises in Florida, the Army said Thursday. 

The students and instructors were hurt early Wednesday evening at Eglin Air Force Base while conducting training on how to protect themselves from lightning. Many were treated and released, but 20 stayed in the hospital overnight. 

The students are near the end of their Ranger training. This class has gained wide attention because, for the first time, two women are expected to graduate from the grueling Ranger course. 

According to Keith Boydston, a spokesman at Fort Benning, Georgia, the two women in the course were not affected by the lightning. 

Col. David Fivecoat, Airborne and Ranger Training Brigade commander, said that 31 of the students returned to their training Thursday and will have increased medical monitoring as they try to earn their Ranger tab. 

Earlier this year, the Army for the first time allowed women to participate in the previously all-male Ranger course, but none passed. Some were invited to try again and two women passed the early phases, have completed the most difficult portions of the final phase and are expected to graduate next week, barring injuries or illnesses, according to officials. 

Asked about the women, Gen. Ray Odierno, the Army chief of staff, told reporters on Wednesday that he's been told they are incredibly prepared. 

"The effort that they've put forward has been significant," said Odierno. "They've impressed all that they've come in contact with. They are clearly motivated and, frankly, that's what we want out of our soldiers." 

He said that the Army is likely to run another gender-integrated Ranger course in November and at that point will decide whether it will be permanently open to women.