MPH 540 Week 4 Occupational Hazard Assessment Example

Noise, Heat, Fumes and Molten Metal: An Occupational Hazard Assessment of the Melt Shop at a Southern Colorado Steel Mill

[Student Name]

University of Phoenix

MPH/540: Environmental and Occupational Health Management

Week 4 Assignment

[Instructor Name]

[Date]

The mill, its melt shop, workers, measurements, injury records and programs are composites written for a model paper; research findings come from the sources cited.

In March, the melt shop supervisor at the county's steel mill filed a note with the safety office: a third furnace operator that month had complained of ringing ears after a shift. The mill's safety manager asked the county's environmental health office and a university occupational health program to help assess the shop's hazards. This paper presents that assessment, organized by task and hazard type.

The Workplace

The melt shop is the heart of the mill. About 240 workers across four rotating crews charge scrap into two electric arc furnaces, melt it with electrodes, refine the steel in a ladle furnace, tap molten metal and cast it into billets. The work runs around the clock. Contract crews handle furnace relining, maintenance and slag removal. The mill has operated on the same site for more than a century, and parts of the melt shop building date from earlier expansions, so newer controls have been fitted into older layouts. Aisles are narrow, and some control pulpits sit close to the furnaces, which affects how far workers can be separated from noise and heat.

The Tasks

Each task carries its own hazards. Charging involves cranes lifting scrap buckets overhead. Melting produces intense noise, heat and fumes. Tapping and ladle work bring workers close to molten metal. Casting and billet handling involve moving equipment and heavy lifting. Relining requires work inside a cooled but still hot furnace shell.

Physical Hazard: Noise

Electric arc furnaces are among the loudest industrial processes. Personal dosimetry on 30 workers across tasks found eight-hour average noise levels from 88 to 101 decibels, with furnace operators and crane operators highest. All measured workers exceeded 85 decibels, the level at which OSHA requires a hearing conservation program.

Noise in National Context

The mill is not unusual. A national survey analysis estimated that about 22 million US workers, 17% of the workforce, reported exposure to hazardous workplace noise, with the highest prevalence in mining at 76%, and that 34% of exposed workers reported not using hearing protection (Tak et al., 2009). Globally, 16% of disabling hearing loss in adults, more than 4 million disability-adjusted life years, is attributed to occupational noise, with larger effects in men (Nelson et al., 2005). Hearing lost to noise does not come back, and it is almost entirely preventable.

Hearing Test Results

The mill's audiometric records showed that 27% of melt shop workers with at least five years of service had a standard threshold shift, a measurable worsening of hearing, compared with 9% of office staff. Workers reported inconsistent use of earplugs, citing discomfort in heat and difficulty hearing radio calls. Several described removing plugs to talk with crane operators, which means the loudest moments of the shift may be the least protected. Fit testing of hearing protection had never been done, so no one knew how much attenuation workers actually received.

Physical Hazard: Heat

Heat is constant near furnaces and ladles, and summer adds to it. Wet bulb globe temperature readings near the tapping platform exceeded recommended limits for heavy work on most summer afternoons. Workers wear heavy protective clothing that traps heat. Water stations were available but located away from the tapping platform, and breaks in cooled rooms depended on crew staffing. Workers returning from vacation or illness were given no gradual return to heat, although acclimatization fades within a week or two away from hot work.

Heat in National Context

Workplace heat kills. An analysis of national fatality records identified 359 heat-related worker deaths from 2000 through 2010, an average rate of 0.22 per million workers, with the highest rates among Hispanic workers, men, agriculture and construction and very small employers (Gubernot et al., 2015). The mill recorded four heat illness cases requiring medical care in the past three summers, all in the first two weeks of hot weather or among new workers.

Chemical Hazard: Metal Fumes

Melting scrap releases fumes containing iron oxide, manganese, zinc and other metals. Personal air sampling found manganese exposures for furnace operators averaging about half the mill's internal limit, with two samples during relining above it. Manganese can affect the nervous system with long exposure, producing tremor and changes in movement and mood.

Chemical Hazard: Dust and Gases

Slag handling and refractory work release silica-containing dust. Carbon monoxide can accumulate near the furnaces and in enclosed spaces. The mill uses fixed carbon monoxide monitors, but contract crews do not always carry personal monitors. Respirators are required during relining, yet the mill's records showed that fit testing for contract workers was the contractor's responsibility and was not verified by the mill.

Safety Hazard: Burns and Molten Metal

Molten metal splashes and furnace eruptions can cause severe burns. The injury log recorded 11 burns in three years, two requiring hospitalization, most during tapping and ladle work.

Safety Hazard: Struck-By and Crane Work

Overhead cranes move buckets weighing many tons. Two near misses involving swinging loads were reported last year. Mobile equipment moving billets creates risk of struck-by injuries in narrow aisles.

Ergonomic Hazards

Relining, maintenance and billet handling involve heavy lifting, awkward postures and vibration from tools. Musculoskeletal injuries, mainly back and shoulder strains, were the most common recordable injury in the log, 34 of 92 over three years.

Psychosocial Hazards

Rotating 12-hour shifts, overtime during outages and production pressure contribute to fatigue. Workers described skipping breaks in heat to keep production on schedule. Fatigue raises the risk of errors around molten metal and cranes. Three of the 11 burns occurred in the last two hours of a 12-hour shift, a small number but a pattern worth watching.

Workers at Highest Risk

Exposure is uneven. Furnace and crane operators face the most noise and heat. Contract relining crews face the highest fume, heat and ergonomic exposures but receive less training and are less likely to be enrolled in the mill's hearing program. New workers have not acclimatized to heat, and older workers may have existing hearing loss. Many contract workers are Hispanic, consistent with national heat mortality patterns.

The Costs

Occupational injury and illness is expensive. A national estimate put the 2007 cost of workplace injuries and illnesses at about $250 billion, with 73% in indirect costs such as lost productivity, and injuries accounting for 77% of the total (Leigh, 2011). For the mill, lost workdays, workers' compensation and replacement training make prevention a business interest as well as a health one.

Ranking the Hazards

The team ranked hazards by severity, number of workers exposed and exposure above limits. Noise ranked first, affecting nearly all melt shop workers above the action level with evidence of hearing loss. Heat ranked second, given its seasonal rise and potential for death. Burns and struck-by risks ranked third for severity. Manganese during relining, musculoskeletal strain and fatigue followed.

Limits of the Assessment

The dosimetry sample was small, and air sampling covered only two relining events. Injury logs likely undercount minor injuries and illnesses such as hearing loss that develop slowly. Contract workers' injuries may be recorded by their employers rather than the mill.

Conclusion

The melt shop exposes its workers to noise, heat, metal fumes, molten metal, heavy loads and fatigue, with contract crews and new hires carrying the most risk. Measurements and records show noise above action levels for every worker sampled and early hearing loss among experienced staff. National evidence on noise exposure, hearing loss and heat deaths confirms these are serious, common and preventable. The next paper applies the hierarchy of controls to the top-ranked hazards.

References

Gubernot, D. M., Anderson, G. B., & Hunting, K. L. (2015). Characterizing occupational heat-related mortality in the United States, 2000-2010: An analysis using the Census of Fatal Occupational Injuries database. American Journal of Industrial Medicine, 58(2), 203-211. https://doi.org/10.1002/ajim.22381

Leigh, J. P. (2011). Economic burden of occupational injury and illness in the United States. The Milbank Quarterly, 89(4), 728-772. https://doi.org/10.1111/j.1468-0009.2011.00648.x

Nelson, D. I., Nelson, R. Y., Concha-Barrientos, M., & Fingerhut, M. (2005). The global burden of occupational noise-induced hearing loss. American Journal of Industrial Medicine, 48(6), 446-458. https://doi.org/10.1002/ajim.20223

Tak, S., Davis, R. R., & Calvert, G. M. (2009). Exposure to hazardous workplace noise and use of hearing protection devices among US workers: NHANES, 1999-2004. American Journal of Industrial Medicine, 52(5), 358-371. https://doi.org/10.1002/ajim.20690