A 10th-grade student was badly burned while grinding metal in
his school’s metal shop when sparks ignited his clothing. He was
unsupervised when the accident happened and was wearing minimal
protective equipment.  The student was working on a science
project in the shop during his study-hall period. The shop
instructor was two rooms away teaching a wood-shop class. He had
given the student permission to work with tools in the metal
shop and was checking on him occasionally.  Shop students had
learned about handheld angle grinders along with other
metalworking equipment earlier in the semester through their
textbook and in-class instruction. The instructor taught shop
students how and when to operate the grinder, but he didn’t
discuss the grinder’s potential hazards like sparks and
fragmenting wheels.  The manual for the grinder involved in the
accident notes that sparks from the grinding wheel can ignite
nearby flammable materials. It also calls for an operator to
wear a “face shield or at least safety goggle