Hazards in Tunnel Finish Construction One major project on the Boston Big Dig was the construction of the Ted Williams Tunnel. As part of finish, the tunnel was covered with 1.4 million 8 inch square tiles each placed separately, by hand. Tiling work was done by Laborers and Masons Work was done in the enclosed tunnel alongside of other construction activities (diesel equipment, concrete chipping and grinding etc)

Tilers To tile the tunnel walls the tilers performed several tasks: –Mixing mastic –Applying mastic on wall –Placing tiles on wall on top of mastic –Mixing grout –Applying grout on top of tiles –Wiping off excess grout Individual tilers tended to do one or two of these tasks on a given day, but all of these tasks over the workweek.

Flow Chart of the Process 1 SAMPLE Another SAMPLE

Pick 1 task to discuss Applying Mastic.. Chemical Hazard Mastic is an epoxy containing organic solvents, and bisphenol-epichlorohydrin polymer and activator Causes respiratory and skin irritation and neurotoxicity Exposure Intensity: –Airborne moderate (highest VP = 10) –Dermal high (organic hydrocarbons easily absorbed) Duration of exposure: all day

Stay with the 1 task you chose to discuss Applying Mastic…Chemical Controls Controls in use: none Work area hygiene: poor Recommended controls: –Consider substitution to alternative wall coating such as aluminum panels on walls –Consider substitution of less toxic mastic –Use neoprene gloves, chemical worker goggles, coverall –Improve general ventilation in area

Stay with the same task you chose for Chem Hazard unless no Ergo hazard then pick another task Applying Mastic.. Ergonomic Hazard Repetitive hand/wrist motion and awkward wrist postures Extreme shoulder elevation when applying mastic above shoulder height Kneeling and/or stooping when applying mastic near floor level of the scaffold OSHA checklist A score –Mastic: 9

Stay with the task you chose for Ergo Applying Mastic…Ergonomic Controls Controls in use: none Recommended controls: –Consider substitution to alternative wall coating such as aluminum panesl on walls –Adjust scaffolding to keep work between knee and shoulder –Rotate workers between other tasks during the day Tiling, applying mastic/grout, mixing mastic/grout

General Job Hazards General safety hazards of this job include: –Use of scaffolding –Poor lighting –Underground worksite –Other?? General psychosocial issues with this job include: –Poor job security –Little latitude in job assignment –Other????

Summary of Tiler Job While tiling, the workers were exposed to chemical hazards from the mastic and grout, as well as ergonomic hazards from the repetitive motion of tiling. Process redesign would be the first choice for control of the hazard. Alternatives include: –Substitution of alternative wall coating such as aluminum panels or use of less toxic mastic and grout –Use of appropriate PPE –Adjust workstation to keep work between shoulder and knees –Rotation between job tasks