The grate is located in front of the Shaare Torah Girls Elementary School.
The school is ultra-Orthodox Jewish with about 260 students in grades first through eighth.
More than 20 girls were standing on the grate taking end of the year pictures at the time of the collapse.
The children fell about 15 feet into the basement. They crawled into a basement window to safety. Police say 36 people with various injuries were treated.
The injured were transported to Lutheran Medical Center, Maimonides Medical Center, and Methodist Medical Center. All were listed in stable condition. Officials said two of them suffered serious bone fractures.
EMS and Hatzolah paramedics put the children on backboards in front of the school and rushed them to waiting hospitals.
The cause of the Friday morning collapse is under investigation.
School officials declined to comment.
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