Hazards in Tunnel Finish Construction

1. 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)

2. 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.

3. Flow Chart of the Process 1 SAMPLE Another SAMPLE

4. Pick 1 task to discussApplying 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

5. Stay with the 1 task you chose to discussApplying 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

6. Stay with the same task you chose for Chem Hazard unless no Ergo hazard then pick another taskApplying 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

7. Stay with the task you chose for ErgoApplying 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

8. 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????

9. 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