black lung february, 2009 wv coal association charleston, wv tmtm the findings and conclusions in...

Black Lung

February, 2009

WV Coal Association

Charleston, WV

TM

The findings and conclusions in this poster have not been formally disseminated by NIOSH and should not be construed to represent any agency determination or policy.

50th wedding anniversary, 1971

My Maternal Grandfather

Died age 96

Coal miner in the Somerset

coalfield, England

Black Lung

• Collection of diseases– Pneumoconiosis– Chronic obstructive pulmonary disease– Emphysema

Pneumoconiosis

– Fibrotic diseases of the lungs caused by inhalation of dusts

– Coal workers’ pneumoconiosis (CWP), from coal mine dust

– Severe form is Progressive Massive Fibrosis (PMF)

– Silicosis, from silica dust– Both can lead to disability and premature

mortality– Very difficult to distinguish between them on

the x-ray

PMF‘Simple’ CWP

Progressive massive fibrosisComplicated pneumoconiosis

Normal

Pneumoconiosis is not caused by

smoking!…

Disease Prevention

• Primary disease prevention– Dust control– Alternatives– Ventilation– Respirators

• Secondary disease prevention– Early detection of disease and

reduction/elimination of further exposure

NIOSH coal miner programs

• NIOSH runs two related programs for worker monitoring for pneumoconiosis– Regular program – mine-based using clinics

to obtain x-rays– Enhanced program – community-based using

NIOSH mobile van

NIOSH coal miner programs

• Both programs have two major uses –– Secondary disease prevention through

entitlement to a low dust working environment if pneumoconiosis is seen

– Population surveillance data to monitor effectiveness of dust control, identify problems, and assess trends.

Secondary prevention

• May slow down or prevent severe disease development

• My grandfather left coal mining when pneumoconiosis was found

• However, those with simple pneumoconiosis are at greatly increased risk of severe disease, regardless of future dust exposure

• Secondary prevention reduces the likelihood of future severe disease but does not prevent its development

• Only adequate dust control prevents disease

National surveillance findings

CWP hot spot areas

CWP Hot Spot Areas

1970-1974

1975-1979

1980-1984

1985-1989

1990-1994

1995-1999

2000-2004

2005-2006*

Per

cen

tag

e

0

5

10

15

20

25

30

35

0-9 years10-14 years15-19 years 20-24 years25+ years

Tenure in Mining

Percent of miners with CWP by tenure in mining, 1970-1999

Percent of miners with CWP by tenure in mining, 1970-2006

1970-1974

1975-1979

1980-1984

1985-1989

1990-1994

1995-1999

2000-2004

2005-2006*

Per

cen

tag

e

0

5

10

15

20

25

30

35

0-9 years10-14 years15-19 years 20-24 years25+ years

Tenure in Mining

Number of miners with any CWP by age, 2000-2009

0

50

100

150

200

250

300

30 - 39 40 - 44 45 - 49

Age (years)

Nu

mb

er

Number of miners with severe CWP by age, 2000-2009

02468

1012141618

30 - 39 40 - 44 45 - 49

Age (years)

Nu

mb

er

Deaths with CWP, age 15-44, national data

0

5

10

15

20

25

30

1960 1970 1980 1990 2000 2010

Rising?

A recent death with severe CWP

Died age 6627 years as a coal miner

17 years underground

West Virginia

Mortality with CWP

CWP Mortality rates – highest counties in the nation

WV in 2008 – pneumoconiosis observed

• 1,517 coal miners examined in NIOSH program– Mean age = 47 years– Mean mining tenure = 22 years– 91 with any pneumoconiosis– 23 with PMF

WV in 2008 – expected

0102030405060708090

100

Any pneumoconiosis PMF

Observed

Expected: 1 mg/m3

~6 times ~15 times

Reasons for increase

• Longer hours worked?• Greater production?• Inadequate compliance for coal mine dust?• Increased exposure to silica dust?• Inadequate compliance method for silica?• (Dust limits are too high)

Reasons for increase

• Longer hours worked?• Greater production?• Inadequate compliance for coal mine dust?• Increased exposure to silica dust?• Inadequate compliance method for silica?• (Dust limits are too high)

Hours worked/year

hours/miner

1500

1700

1900

2100

2300

1975 1985 1995 2005

hours/miner

Data from MSHA website

Reasons for increase

• Longer hours worked?• Greater production?• Inadequate compliance for coal mine dust?• Increased exposure to silica dust?• Inadequate compliance method for silica?• (Dust limits are too high)

West Virginia coal employment and productivity

Miners

Productivity

Reasons for increase

• Longer hours worked?• Greater production?• Inadequate compliance for coal mine dust ?• Increased exposure to silica dust?• Inadequate compliance method for silica?• (Dust limits are too high)

WV coal mine dust levels

0

0.1

0.2

0.3

0.4

0.5

0.6

NorthWV

SouthWV

WestPA

EastKY

VA

1995-2003

All years

“Using two statistical approaches, data from three mining occupations in 54 large underground coal mines during 1976-1978 are examined for evidence of underreporting…Both approaches suggest widespread underreporting.”

0

0.5

1

1.5

2

1 -1415 - 24

25 - 34

35 - 49

50 - 74

75 - 124

125 - 224

225 - 334

335 - 999

Mine size

Du

st l

evel

(m

g/m

3)

Inspector Operator

MSHA Special Inspection survey, 1991

Reasons for increase

• Longer hours worked?• Greater production?• Inadequate compliance for coal mine dust?• Increased exposure to silica dust• Inadequate compliance method for silica?• (Dust limit are too high)

WV in 2008 – expected

0102030405060708090

100

Any pneumoconiosis PMF

Observed

Expected: 1 mg/m3

~6 times ~15 times

WV in 2008 – pneumoconiosis expected (3)

0102030405060708090

100

Anypneumoconiosis

PMF

Observed

Expected: 3.3 mg/m3

Implication

• Another factor apart from excessive coal mine dust exposure at work

• Preliminary findings from our program support the interpretation that the increase is partly due to an increase in silicosis

Historical evidence

Reasons for increase

• Longer hours worked?• Greater production?• Inadequate compliance for coal mine dust?• Increased exposure to silica dust?• Inadequate compliance method for silica?• (Dust limits are too high)

WV silica dust levels

0

0.01

0.02

0.03

0.04

0.05

0.06

NorthWV

SouthWV

WestPA

EastKY

VA

1995-2003

All years

“Although all of the analytical methods for crystalline free silica area sufficiently sensitive to be able to detect and quantitate free silica at environmentally significant concentrations, they

are all plagued with similar difficulties.”

Summary – What we know

• Prevalence of pneumoconiosis in miners with 20+ years of tenure x-rayed in the NIOSH monitoring program is rising

• Cases of severe disease continue to be seen in younger workers (<40 years old)

• Prevalence of pneumoconiosis far greater than expected from reported dust levels

Summary – What we are unsure about

• Exact cause of increase in prevalence and severity is not known

• Multiple causes may be at work– Longer hours worked– Inadequate compliance coupled with increased

productivity– Thin seam mining due to depletion of best coal

reserves, leading to excess silica exposure and silicosis

– Lack of knowledge/resources in small mines

Primary Solutions

• Modify compliance method for coal dust including use of personal dust monitor (being tested by NIOSH)

• More state assistance in county extension work for smaller mines?

• Adopt NIOSH recommended exposure limits for coal mine dust and silica levels

• Change compliance assessment method for silica dust (NIOSH recommendation)

Take Home Message

• Black Lung is entirely preventable using dust control

• No other prevention method (respirators, x-rays) can guarantee such success

• It behooves every employer and employee to minimize dust production

• Especial care is needed when rock is being cut

0

100

200

300

400

500

600

700

1 -1415 - 24

25 - 34

35 - 49

50 - 74

75 - 124

125 - 224

225 - 334

335 - 999

Mine size

Pro

du

ctio

n (

ton

s)

Inspector Operator

MSHA Special Inspection survey, 1991

Effect of coal rank

Effect of coal rank

Dust levels pre-1969 and in the early 1970s

WV silica levels in coal mines

NIOSH REL = 0.05 mg/m3

Dust levels in WV mines