Task Prior to Abatement (Description)
An ergonomic case study for workers at Newport News Shipbuilding. Newport News shipbuilding builds nuclear powered aircraft carriers and nuclear submarines. There were increasing rates of wrist injuries and back injuries in the welding department and maintenance department, respectively, in late 1996. In the welding department, in the early 1990s, the welders primarily used a stick welding type of arch welding. A stick of weld rod was about 14 inches long and it was placed in an electrode holder. The electrode holder was similar to an automobile jumper cable clamp. The welder holds the clamp and strikes an arc between the weld rod and the workpiece. Later on, the company changed the welding technique and switched to a wire-fed technique. Because of less physical task variety and more static postures, this method caused more wrist problems among welders. In the maintenance department, workers had to manually lift and carry heavy parts, apply high static muscle loads, do electrical work, and pipe fitting and iron work.
Task Prior to Abatement (Method Which Identified Hazard)
- Increasing ergonomics injury incidence rate to about 13 per 10,000 full-time workers in late 1994.
- 45 percent increase in ergonomics injury incidence rate during the first 10 months of 1994.
- Sharp increase in wrist injuries, carpal tunnel syndrome, tendonitis and tenosynovitis, since switching welding techniques.
- Recording between 2 and 4 wrist injuries every month.
- Averaging about one back injury in the maintenance department every month through about July 1995.
Ergonomic Risk Factor (Force)
Lifting and carrying heavy objects was required to perform maintenance tasks.
Ergonomic Risk Factor (Posture)
Long static postures were required to perform the welding task.
Workers had to perform welding with wrists in a non – neutral position.
Workers had to perform the welding task above shoulder height
Ergonomic Solution (Administrative Controls)
- Initiating training classes covering the nature of CTDs, anthropometry, work physiology, back and wrist anatomy and proper work techniques.
- Evaluating and developing intervention for the welding department.
- In-depth training course covering tool selection, work habits, alternating trigger fingers and hands.
- Selecting pistol grip and in-line based tools by workers so as to keep the wrists in a neutral posture.
- Instituting a training program covering the anatomy of the back, how it works, how to lift and split loads.
Ergonomic Solution (Engineering Controls)
- Installing scaffolding at the right height and distance from the work.
- Using ladders or installing scaffolding to higher positions for the work above shoulder height.
- Splitting the load into two or more smaller boxes and making more than one trip to lift and carry the parts.
Ergonomic Solution (Benefits)
- All workers that perform the tasks now have reduced exposure to all kinds of CTDs risk factors.
- Educating 882 employees in 41 classes during 1996.
- Performing 65 formal workstation evaluations during 1996.
- Saving $1.4 million in workers compensation costs.
Ergonomic Solution (Cost)
Information not available. However, there was no material or capital budget for special projects. New equipment was purchased through the appropriate department budgets.
Ergonomic Solution (Method Which Verified Effectiveness)
- Eliminating wrist injury in the welding department until March 1996.
- Decreasing to only 6 lost time ergonomics wrist injuries through November 1996, since training completed in June 1995.
- Eliminating lost time back injury since July 1995.
- Reducing the ergonomics injury incidence rate to less than 6 in January 1996 and to less than 7 in October 1996, which is half the rate from last year.
- Reducing ergonomics case rates about 30 percent during 1996.
- Reducing lost time ergonomics case rates up to 55 percent.
The key to success for the Newport News ship-building company was the broad-based program that embraces employee involvement and team-work with organized labor.
CTD News, January 1997, Training a ‘limbsaver’ at Newport News, CTD News.