Health Hazard Evaluation Report, HETA-99-0084-2807, Haverhill High School, Haverhill, Massachusetts.
On January 27, 1999, the National Institute for Occupational Safety and Health (NIOSH) received a confidential request from staff at Haverhill High School in Haverhill, Massachusetts, for an evaluation of exposures to crystalline silica and other compounds in ceramics. The request indicated that employees were concerned about developing emphysema, silicosis, and/or asthma due to exposure to ceramics materials. In addition, the request indicated that staff were concerned about exposures to various materials used in five art rooms, and the woodworking shop. On April 27, 1999, an initial site visit was conducted which included an opening conference, informal discussions with teachers, and a walk-through inspection of the art rooms and woodworking shop. During the walk-through, activities were identified in ceramics and woodworking classrooms which could result in exposure to crystalline silica, metals, and wood dust. On May 4, 1999, a second site visit was conducted where environmental monitoring was conducted for airborne crystalline silica in the ceramics classroom, and wood dust in the woodworking shop. Surface wipe sampling for metals was conducted in ceramics. Measured concentrations of respirable crystalline silica were below the NIOSH Recommended Exposure Limit (REL) during the monitoring period. Neither of the respirable area samples revealed detectable levels of crystalline silica. Total crystalline silica (quartz) concentrations of 0.070 milligrams per cubic meter (mg/m3) and 0.075 mg/m3 were quantified in bulk air samples collected at the wedging table and at the center of the classroom, respectively. A bulk sample of settled dust, collected from a shelf adjacent to the door leading to the corridor, contained 25% quartz. Cristobalite was not detected in any of the samples. Gravimetric analysis of air samples indicates that concentrations of all airborne particulates were below occupational exposure limits for particulates not otherwise regulated (PNOR). Surface wipe sampling for metals found the highest concentrations of metals in the storage closet where glazes are prepared from powdered materials. Local exhaust ventilation (LEV) is not provided at the wedging table or in the glaze preparation area. The highest concentration of wood dust (3.4 mg/m3 during a 50-minute period) was measured in the personal breathing zone (PBZ) sample collected on the woodworking instructor. A similar concentration (3.2 mg/m3 during a 78-minute period) was measured in the vicinity of two students who were using hand-held orbit sanders at a "homemade" downdraft table. The presence of crystalline silica in a settled dust sample indicates a need for LEV and appropriate housekeeping practices in the ceramics classroom. Air samples collected in the woodworking shop indicate that current LEV is not providing effective control of wood dust. Recommendations include substituting premixed glazes, installation of effective LEV systems in ceramics and woodworking classrooms, improved housekeeping practices in ceramics, and implementation of an effective Chemical Hazard Communication Program.