Health Hazard Evaluation Report, HETA-92-0311-2826, CSX Transportation, Inc., Nashville, Tennessee.
In June 1992, the Dixie Federation of the Brotherhood of Maintenance of Way Employees (BMWE) requested a National Institute for Occupational Safety and Health (NIOSH) health hazard evaluation (HHE) of railroad track maintenance operations conducted by CSX Transportation, Incorporated (CSXT). The request concerned respiratory hazards to maintenance of way (MOW) employees from dusts generated while these operations are performed "in and around Radnor Yard in Nashville, Tennessee and at most trackage in Tennessee as well as other southern states." Subsequent to the request, the Dixie Federation merged with other federations and assumed the name of the Allied Eastern Federation of BMWE. On November 9, 1992, NIOSH representatives met with company and union representatives for an initial meeting and brief site visit near Radnor Yard. NIOSH then conducted environmental air sampling at eight sites during track maintenance activities between August 1993 and April 1997. Twenty-two area samples and 185 personal samples were collected for respirable dust and respirable crystalline silica. Area and personal respirable dust 10-hour time-weighted average (TWA) concentrations ranged from "not detected" to 1.04 mg/m3 and "not detected" to 2.05 mg/m3 , respectively. The range of 10-hour TWA respirable crystalline silica (as quartz) concentrations for the area samples was "not detected" to 0.30 mg/m3 and was "not detected" to 0.43 mg/m3 for the personal samples. Cristobalite, another form of crystalline silica, was not detected on any of the samples. Eighteen of the personal sample concentrations exceeded the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) for respirable dust, and 28 exceeded the NIOSH Recommended Exposure Limit (REL) for respirable quartz; these samples were obtained on ballast regulator, broom, and tamper operators as well as track repairmen engaged in ballast dumping. In an effort to reduce worker exposure, the company was modifying operator cabs on equipment. The cabs were being rebuilt with air-conditioning and pressurization systems, and seals were being provided around doors, windows, and levers. Real-time dust measurements showed the effectiveness of these modifications to one such cab. Manual control of ballast car hopper doors was being replaced with radio remote control. NIOSH recommendations include substitution with ballast that contains less crystalline silica, wetting of the ballast to prevent dust, and maintenance of the operator cabs. NIOSH investigators determined that a health hazard existed for railroad track maintenance workers from occupational exposure to crystalline silica. The presence of this risk was indicated by personal measurements of airborne respirable crystalline silica that exceeded occupational exposure guidelines. The hazard was greatest for workers who operated ballast regulating, broom, and tamping machines and for track repairman who dumped ballast. Reduction of worker exposure to airborne dust is recommended to protect the health of the workers engaged in these activities.