Disease and Illness in U.S. Mining, 1983–2001
 

Douglas F. Scott, MPH

R. Larry Grayson, PhD

Edward A. Metz, MD

From National Institute for Occupational Safety and Health, Spokane Research Laboratory, Mining 

Injury and Disease Prevention Branch, Spokane, Washington; University of Missouri-Rolla, MO, 

Mining Engineering Department, Rolla, Missouri; and Gilmore, Metz & Associates, Crawford, 

Nebraska. 

Address correspondence to: Douglas F. Scott, National Institute for Occupational Safety and Health, 

Spokane Research Laboratory, Mining Injury and Disease Prevention Branch, 315 E. Montgomery 

Ave., Spokane, WA 99207. E-mail address: dus3@cdc.gov. 

This article was co-written by an officer or employee of the US Government as part of his official 

duties and is therefore not subject to US copyright. 

Objectives: We describe inconsistencies in disease and illness reporting in U.S. mining, identify under-reporting of disease and illness in 

U.S. mining, and summarize selected disease and illness in U.S. mining 

from 1983 through 2001. Methods: We summarized information on 

mining-related disease and illness data for the years 1983–2001 from 

the Mining Safety and Health Administration database (MSHA). 

Results: Discrepancies exist in types of information collected by the 

Centers for Disease and Control, the National Institute for Occupational Safety and Health, and the Mining Safety and Health Administration database. Several factors, including a worker’s fear of losing 

his or her job, health insurance, or other job-related benefits contribute to 

under-reporting of disease and illness information in the US mining 

industry. Conclusions: Since 1997, both number of workers employed in 

mining and disease and illness rates have decreased; however, the 

highest disease and illness rates in mining continue to be coal worker’s 

pneumoconiosis and hearing loss. (J Occup Environ Med. 2004;46:

1272–1277)

Miners are exposed to various potentially toxic or harmful materials or 

agents, including, but not limited to, 

fuels, reagents, solvents, detergents, 

chemicals, coal dust, silica dust, diesel particulate matter (DPM), asbestos, noise, welding fumes, poisonous 

plants, trona dust, and metal dust. 

Disease and illness exposures can be 

classified as either chronic or acute. 

An acute or accelerated disease or 

illness develops during a brief period 

of time and is generally severe in 

nature, that is, a short exposure of 

high intensity.1 A chronic disease or 

illness develops during a long period 

of time and is generally of low intensity.1 The U.S. National Center for 

Health Statistics defines “chronic” as 

a condition lasting 3 months or 

more.1 The process of contracting an 

occupational disease or illness can be 

slow (ie, months or years), and miners may be exposed to a toxic or 

harmful agent for years and not exhibit any effects of exposure. 

For the purposes of this article, 

disease and illness are defined as 

“any disease or illness employees 

contract while employed as miners 

and which could be caused by mining activities.” Specific mining disease and illness topics discussed in 

this article include coal worker’s 

pneumoconiosis (CWP), silicosis, 

lung disorders caused by DPM, 

asbestosis, hearing loss or impairment, physical disorders resulting 

from exposure to lead and welding 

fumes, and dermatitis/skin disorders. The Mining Safety and Health 

Administration database (MSHA) 

data from 1983 to 2001 are used 

to frame the level of disease and 

illness. 

For a toxic substance (gas, liquid, 

solid, or vapor) to produce a harmful 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Fig. 1. Disease and illness in the mining industry. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TABLE 1

Data Collection Categories by Agency

NIOSH CDC MSHA

Lung disorders

Occupational lung diseases X

Chronic obstructive pulmonary disease X

Dust diseases of the lungs X

Coal-workers pneumoconiosis X X

Asbestosis X X

Silicosis X X

Byssinosis X

Asthma X

Respiratory conditions caused by toxic agents X X

Repetitive motion

Carpal tunnel syndrome X

Tendonitis X

Disorders associated with repeated trauma X

Other

Neurotoxic disorders X

Noise-induced hearing loss X X

Dermatologic conditions X X X

Psychological disorders X X

Severe occupational traumatic injuries X

Reproduction disorders X

Poisoning X X

Disorders caused by physical agents other than X

toxic agents

Malignant pleural neoplasm X

Occupational cardiovascular diseases X

Lead toxicity X

Pesticide and insecticide toxicity X

Hepatitis B X

Hepatitis C X

AIDS X

effect on a miner, the miner must be 

exposed to the harmful material. Entry routes into a miner’s body include inhalation; absorption through the skin, eyes, or mucous membranes; ingestion; or ears. 

Data Collection

There are many limitations on the 

accuracy of illness reporting. Defining what constitutes disease or illness is sometimes confusing and often depends on which agency is 

reporting the data. Table 1 summarizes different ways Centers for Disease Control and Prevention (CDC), 

National Institute for Occupational 

Safety and Health (NIOSH), and 

MSHA categorize disease and illness 

in their databases. All three agencies 

list mining as an occupational category. 

Comparing data from each agency 

(Table 1) is difficult. For example, if 

researchers wanted to compare reproduction disorders from each data 

set, the only agency that lists reproduction disorders is NIOSH. Another 

example is lead toxicity, which is 

only found in CDC’s data set. Therefore, with so many different variables used by various agencies, it is 

nearly impossible for researchers to 

get a clear picture of disease and 

illness in US mining. 

Under-Reporting

Under-reporting is one of the most 

serious issues in understanding disease and illness in the mining industry. Karr recognized that is was “difficult for the Occupational Safety 

and Health Administration (OSHA) 

or anyone else to recognize when 

health hazards at work cause illnesses, because there is often such a 

long lead time for the disease to 

develop.”2 Therefore, cancer and 

other deaths from such hazards, although significantly higher than the 

work site injuries, remain a murky 

area. Fig. 1 depicts the relationship 

between reported and unreported disease and illness and illustrates the 

magnitude of the problem.3 

In the first case of under-reporting, 

an illness is recognized as being 

related to work. A miner is aware of 

the disease or illness but may be 

afraid of reporting the disease because of fear of losing his or her job, 

health insurance, or other job-related 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

benefits. Therefore, the disease or 

illness is not reported. In the second 

case, medical attention is received, 

but neither the attending physician 

nor the miner associates the disease 

with the work environment. Again, 

the disease or illness is not reported. 

In the third case, the miner has symptoms of a disease, but no medical 

attention is sought, and the disease or 

illness is not reported. This again 

could be because of fear of losing 

one’s job, health insurance etc. 

Fourth, a miner could be affected 

with a disease but has no symptoms 

of the disease. Finally, the only disease and illness data collected by 

MSHA is from miners who are employed when symptoms of the disease or illness are apparent. Disease 

and illness data from workers who 

have retired or left their job and 

subsequently develop a disease or 

illness that was work related will 

seldom be reported. In short, it is 

probable that even with the limited 

disease and illness data currently 

available, the number of miners who 

actually have a disease or illness 

caused by mining may be significantly greater than reported (based 

on Karr’s work). 

Disease and Illness Rates

The total number of miners (underground and surface metal and 

nonmetal) employed in the mining 

industry is shown in Fig. 2. Since 

1984, there has been a steady decline 

in the number of workers employed 

in the mining industry, even though 

some years realized marginal 

growth. 

As indicated in Fig. 3, mining had 

a nonfatal occupational illness incidence rate of 18.8 per 10,000 fulltime workers, which is about the 

same rate as for construction workers.4 Although this rate seems low 

compared with the rates in manufacturing or agriculture, the mining incidence rate of nonfatal occupational 

illness and disease could be improved by identifying why and under 

what specific conditions illnesses occur (ie, what are the primary causes 

Fig. 2. Number of persons employed in the mining industry 1983 to 2001. 3 

Fig. 3. Incidence rates of nonfatal occupational illness by industry (1997). 

of illness or disease in the mining 

industry?). 

Table 2 shows U.S. mining disease 

and illness rates from 1983 to 2001 

for all diseases and illnesses and for 

CWP, hearing loss, contagious disease and illness, silicosis, asbestosis, 

and skin disorders. Contagious disease and illness, silicosis, asbestosis, 

and skin disorders are all fewer than 

1.2 per 10,000 workers and are not 

shown in Fig. 4. 

Although the years 1997 through 

2001 show a decrease in the rates of 

disease and illness, CWP, and hearing loss in the mining industry, these 

rates have not returned to the lower 

levels recorded in 1983 to 1984. This 

is true partly because of changes in 

reporting requirements, partly because of more faithful reporting of 

illness and diseases once ignored by 

miners, and partly because of increased recognition of the workrelated nature of illness and disease. 

Many mining companies have emphasized the latter in recent years. 

However, 1997 nonfatal mining 

occupational illness rates reported by 

CDC were 18.8 per 10,000 and 1997 

nonfatal mining occupational illness 

rates reported by MSHA were 35 per 

10,000. This difference can be attributed to the categories of disease or 

illness assigned by each agency and 

is an excellent example of the need 

for uniform data reporting and how 

rates can vary from one agency’s 

reporting compared to another. 

Coal Dust

The Federal Coal Mine Health and 

Safety Act of 1969 defines CWP as a 

“chronic dust disease of the lung 

arising out of employment in an underground coal mine.”5 Progressive 

massive fibrosis is a complicated 

form of CWP and is generally associated with breathlessness, chronic 

bronchitis, recurrent chest illness, 

and even heart failure. Other complications can be increased risk of tuberculosis and mycobacterial infections. Progressive massive fibrosis is 
 

Fig. 4. Disease and illness, CWP, and hearing loss rates from 1983–2001. 3 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TABLE 2

US Mining Disease and Illness Rates, 1983 to 2001 (per 10,000)

Year Disease and Illness CWP Hearing Loss Contagious Disease/Illness Silicosis Asbestosis Skin Disorders

1983 7.0 4.1 0.5 0.2 0.2 0 0.4

1984 5.8 3.7 0.5 0.2 0.3 0 0.4

1985 11.3 7.6 2.2 0.2 0.1 0.2 0.3

1986 26.5 16.5 8.3 0 0.2 0.3 0.2

1987 40.7 26.1 11.5 0.8 0.5 0.3 0.4

1988 32.9 19.0 7.9 0 0.2 0 1.1

1989 26.5 12.3 5.5 0 0.2 0.3 1.5

1990 23.3 9.9 4.1 0.5 0.7 0 0.8

1991 28.7 13.5 5.0 0.3 0.8 0 1.7

1992 32.5 16.8 5.7 0 0.5 0.5 0.8

1993 31.9 15.2 4.9 1.1 0.5 0.3 0.4

1994 29.1 11.8 4.6 0 0.4 0 0.7

1995 21.9 5.8 4.8 0.6 0.4 0.3 0.7

1996 18.5 2.8 3.5 0.8 0.2 0 0.6

1997 35.3 10.3 6.2 0.6 0.5 0.8 1.3

1998 31.7 6.4 7.0 0.8 0.8 0.3 1.1

1999 25.1 3.4 4.6 0 0.2 0.6 0.9

2000 22.4 3.2 4.5 0 0.2 0 0.7

2001 22.2 2.2 4.4 0.3 0.4 0 0.3

a distinct disease and is associated 

with increased mortality. According 

to Kissell and Colinet,6 a study in the 

1990s showed an average of 2.8% 

prevalence of CWP; however, miners with more than 30 years of exposure to coal dust had a prevalence of 

14%. Kissell and Colinet further attributed 18,245 deaths between 1987 

and 1996 to CWP as a direct or 

contributing cause of death, with 

70% of the death certificates listing 

“mining machine operator” as the 

occupation.6 

The permissible exposure limit 

(PEL; unadjusted for quartz content 

greater than 5%) for underground coal 

dust is 2 mg/m3 using an 8-hour timeweighted average (TWA). According 

to Kissell and Colinet, 7.4% of all coal 

mine air samples collected from 1987 

through 1996 exceeded this PEL.6 Table 2 and Fig. 4 show the rate of CWP 

for the years 1983 to 2001. An acknowledged 20- to 30-year latency 

period for CWP does not permit recent 

exposures to be considered as disease. 

Nonetheless, a definite improvement 

in the CWP rate has been recorded, 

especially since 1997. 

Silica Dust

Kissell and Colinet stated that 

chronic silicosis involves at least 15 

years of exposure to silica and that 

from 1987 to 1996, approximately 

421 miners and construction workers 

died from silicosis.6 Again, mining 

machine operators accounted for 

14.7% of the deaths. A nuisance dust 

standard of 10 mg/m3 triggers regulation by MSHA, and from 1987 to 

1996, 15.6% of the dust samples 

collected from metal mines exceeded 

the PEL. Table 2 shows the rate of 

silicosis in the mining industry. The 

rate of silicosis in mining from 1983 

to 2001 was less than 0.8 cases per 

10,000 employees and is not considered to be a major threat to the 

mining community today. 

Diesel Particulate Matter

MSHA’s new Standard on Diesel 

Particulate Matter Exposure of Underground Metal and Nonmetal Miners went into effect July 20, 2002. 

An MSHA DPM exposure level of 

400 fg of total carbon per cubic 

meter of air (equivalent to 500 fg of 

DPM per cubic meter) was set, and 

compliance was mandatory July 19, 

2003.7 Noncompliance after that date 

resulted in MSHA citations. Metz 

noted that in 1998, the American 

Conference of Governmental Industrial Hygienists (ACGIH) proposed a 

threshold limit value-time weighted 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

value (TLV-TWA) of only 50 fg/m3 

for diesel particulates less than 1 fm 

in size and classified diesel exhaust 

as a suspected human carcinogen.8 

Of interest, again noted by Metz, was 

the fact that the ACGIH TLV-TWA 

would require occupational air to be 

cleaner than ambient air.8 Importantly, Schnakenberg estimated the 

technically feasible level of DPM 

control today at 90 fg/m3

.

9 

Metz8 provided a detailed summary of the sources of DPM, how 

particulates affect the body, and a list 

of particulate fractions and their toxicity. He further categorized the clinical manifestations of exposure to 

diesel particulates as either nonneoplastic (acute or chronic) or neoplastic (cancer). Although lung cancer 

can be caused in rats exposed to 

diesel exhaust, the long-term health 

effect on miners is not known. 

Asbestos

Table 2 shows a nearly negligible 

rate for miners’ exposure to asbestos, 

which was less than 0.8 cases per 

10,000 from 1983 to 2001. 

Noise

Table 2 and Fig. 4 show the rates 

for hearing loss from 1983 to 2001, 

which ranged from as low as 0.5 

cases per 10,000 in 1983 and 1984 to 

as many as 11.5 cases per 10,000 in 

1987. The rate from 1999 to the 

present seems to have leveled; however, as of 2001, it was the highest 

rate of the six selected disease and 

illness topics discussed. Noiseinduced hearing loss (NIHL) begins 

gradually and progressively gets 

worse. Problems with this disease 

include loss of the ability to communicate and reduced response to environmental and occupational noise 

and danger. In the mining environment, the effects of NIHL can be 

deadly in specific work situations. 

Bise listed several factors that influence occupational hearing loss.10 

These factors include the following. 

•		Age of employee 

•		Pre-employment hearing impairment; 

•		Diseases of the ear 

•		Sound pressure level of the noise 

•		Length of daily exposure 

•		Duration of employment 

•		Ambient conditions of the workplace 

•		Employee lifestyle outside the 

workplace 

MSHA began enforcing its “noise 

rule” in the year 2000. It did so in 

response to its estimate that 13% of US 

miners (~  37,000) would suffer significant loss of hearing (25 dBA 

[decibals] or higher) at previously prevailing conditions over a working lifetime. Eight hours of exposure to 90 

dBA is the current MSHA-permissible 

noise level, with no exposure to exceed 

115 dBA. Bise concluded that, although some controversy exists on 

whether the 8-hour exposure should be 

90 or 85 dBA, “current steps taken by 

the mining industry should enable future generations of mine workers to 

lead productive and safe lives without 

fear of suffering from occupationally 

based NIHL.”10 

Lead

The MSHA occupational PEL for 

lead is 0.01 mg/m3

. Lead miners are 

normally exposed to lead sulfide. Lead 

sulfide is poorly absorbed when inhaled and only slightly soluble in gastric juice, therefore posing a relatively 

insignificant problem to miners.11 

However, lead oxide and lead sulfate 

are more soluble and do pose problems. The good news is that most lead 

mined is in the form of galena (lead 

sulfide); therefore, lead poisoning is 

normally not a threat to miners. However, mill and smelter workers are 

exposed to lead oxide, which does 

pose a disease or illness threat. 

Welding Fumes

NIOSH lists four gases (acetylene, 

carbon monoxide, oxides of nitrogen, and phosgene) and 18 metals 

(arsenic, beryllium, cadmium, chromium, cobalt, copper, iron, lead, 

magnesium, manganese, molybdenum, nickel, silver, tin, titanium, 

tungsten, vanadium, and zinc) as 

hazardous agents associated with the 

welding process.12 Furthermore, it 

lists asbestos, fluorides, and silica as 

other minerals that create hazards 

during welding. Finally, it views 

electricity, hot environments, noise, 

vibration, ionizing radiation, ultraviolet light, and visible light as 

physical agents that could be harmful to welders. All of the abovelisted agents can cause short and 

long term toxic or harmful effects 

(including cancer), as well as 

death. The importance of studying 

welding fumes is that no current 

data exists to track miners who are 

exposed to welding fumes. Many of 

the symptoms of overexposure to 

welding fumes may be confused 

with other exposures in mining (ie, 

certain chemical exposures). 

Health agencies (CDC, NIOSH, 

and MSHA) responsible for tracking disease and illness in miners 

need to begin tracking miners exposed to welding fumes. 

Skin Disorders

Table 2 shows the rate of skin 

disorders in the mining industry. The 

highest number of skin disorders was 

attributed to unspecified dusts (200 

cases from 1983 to 2001) followed 

by 169 cases attributed to poison ivy 

or poison oak. Although the rate of 

skin disorders is not exceptionally 

high, a review of MSHA records 

shows that many of these illnesses 

can be prevented. Unspecified dusts 

and poison oak or poison ivy contributed to more than 350 illnesses, 

which could have been prevented if 

miners had used the proper personal 

protective equipment. 

Lost Work

The number of days lost to disease 

and illness from 1983 through 2001 

is shown in Fig. 5. Although the 

mining workforce has declined during these years, the number of lost 

workdays resulting from disease and 

illness from 1985 through 2001 are 

greater than the levels reported in 

1983 and 1984. Again, it is possible 

that earlier reporting inconsistencies 

in the 1980s compared with later 
Fig. 5. Number of lost workdays 1983–2001 (MSHA, 2002). 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

reporting in the late 1990s and 

through 2001 are responsible for the 

large difference in the number of lost 

days. However, as of 2001, nearly 

800 days per year had been lost 

because of a miner’s disease or illness, which had a significant impact 

on production. 

Discussion

The inconsistencies in the types of 

disease and illness data collected by 

NIOSH, CDC, and MSHA are an 

obstacle to researchers attempting to 

frame the magnitude of disease and 

illness in US mining. A need for one 

government agency to collect detailed disease and illness data for all 

workers who have worked or are 

working as miners is paramount. Under-reporting is recognized as another obstacle in assessing the magnitude of illness and disease in 

mining. It may not be practical to 

stop under-reporting of disease and 

illness in US mining; however, it 

may be necessary to change reporting procedures to MSHA to get a 

more accurate reporting of all disease and illness that may have been 

associated with occupational exposure. For example, workers must 

never be afraid of losing their jobs 

from reporting an occupational disease or illness. Improvements have 

been made since 1977 in reduction of 

the CWP rate; however, CWP continues to be the highest reported rate 

of disease and illness in US mining. 

Because of the 20- to 30-year latency 

period for CWP it is difficult to 

project whether the rate will continue 

to decrease. Because the rate of silicosis, asbestosis, skin disorders, and 

contagious disease and illness in 

miners are all less than 1.2 per 

10,000, these diseases and illnesses 

are not considered a major threat to 

miners. No data exists on DPM exposure in miners, which is another 

obstacle for researchers to evaluate 

the magnitude of disease and illness 

in US mining. Hearing loss rates in 

miners have decreased since 1998; 

however, noise levels considered 

hazardous have not been identified 

or studied sufficiently. Because lead 

sulfide is not bioavailable to the 

body, miners engaged in mining lead 

ores are not at risk to overexposure. 

Finally, since 1997, the number of 

workers employed in mining has decreased and disease and illness rates 

have also decreased, which is good 

news for the mining industry. 

References

1. Last JM. A Dictionary of Epidemiology. 

2nd ed. New York: Oxford University 

Press; 1988. 

2. Karr A. How Far Have We Come? Safety 

Health 1999;159:36 – 42. 

3. Mining Safetyand Health Administration, 2002. MSHA database. Available 

from: http://msha.gov/ACCINJ/accinj. 

htm; Internet; accessed October 7, 2004. 

4. Centers for Disease Control and Prevention. 2000. Nonfatal Illness. Worker 

Health Chartbook, 2000. 

5. Mining Safetyand Health Administration, 2004a. Available from: http:// 

a257.g.akamaitech.net/7/257/2422/ 

14mar20010800/edocket.access.gpo.gov/ 

cfr_2003/aprqtr/pdf/20cfr718.1.pdf; 

Internet; accessed October 7, 2004. 

6. Kissell FN, Colinet JF. Control of Respirable Dust. In: Karmis M, ed. Mine 

Health and Safety Management. Littleton, CO: Society for Mining, Metallurgy, 

and Exploration, Inc.; 2001:275–295. 

7. Mining Safetyand Health Administration, 2004b. Available from: http:// 

www.msha.gov/30cfr/57.5060.htm; accessed October 7, 2004. 

8. Metz EA. Diesel Particulate Matter—So 

What’s the Big Deal? SME Preprint 01– 

85, Society for Mining, Metallurgy, and 

Exploration, Inc., Littleton, CO. SME 

annual meeting, Denver, CO, Feb. 26 – 

28, 2001, 12 pp. 

9. Schnakenberg, GH Jr. Estimate of technically feasible DPM levels for underground metal and nonmetal mines. Mining Engin. 2001;53:45–51. 

10. Bise CJ. Noise. In: Karmis M, ed. Mine 

Health and Safety Management, Littleton, CO: Society for Mining, Metallurgy, 

and Exploration, Inc.; 2001:297–306. 

11. Pon M, Gilbert-Jones, I. Other industrial 

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Mine Health and Safety Management. 

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and Thermal Cutting (abridged). Washington, DC: Superintendent of Documents, US Government Printing Office, 

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110a, 1988.