Her loose clothing apparently got caught in a machine in Fresno County.
Malachi McFadden suffered third-degree burns on his face, neck and arms after a botched "burning money demonstration" at Redan High School on Aug. 6.
"It knocked us all out of our bed, it was so strong," said Mark Brady, who lives in a neighborhood near the blast site.
The building that went up in flames Thursday night held 85,000 pieces, much of it donated.
Ja’Quarius Taylor, 17, was fatally shot this month. His family says he may have been targeted because he was gay and black.