Standard morbidity ratios for work-related amputations and fractures by occupation, 1979–1981

Journal of Safety Research, Vol. 19, pp. 103-113, 1988 0 1988 National Safety Council and Pergamon Press plc

0022-4375/M $3.00 + .OO Printed in the USA

Standard Morbidity Ratios for Work-Related Amputations and Fractures by Occupation, 1979-1981 Linda

M. Harner

The risk of injury varies with age and sex. Thus, it is possible to draw biased conclusions when considering unadjusted data. Standardized morbidity ratios (SMRs) are summary statements that remove differences in the compositions of the populations under study, permitting unbiased comparisons with respect to certain variables. Workers’ compensation data and census data were combined to calculate SMRs for amputations and fractures by occupation. Based on this analysis, occupations were identified that have a high estimated relative risk of amputations (machinists and heavy equipment mechanics) and of fractures (firefighters and plumbers).

Both amputations and fractures represent significant work-related injury problems. In fact, amputations are listed fourth in the National Institute for Occupational Safety and Health’s (NIOSH) list of the 10 leading workrelated diseases and injuries in the United States (Centers for Disease Control [CDC], 1983). This ranking is based on three criteria: (a) frequency of occurrence, (b) severity, and (c) amenability to prevention. In 1983, an estimated 11,300 workers suffered amputations (U.S. Department of Labor, 1983). Approximately 93% of all ampu-

Linda M. Harner was an epidemiologist in the Data Analysis Section, Injury Surveillance Branch, Division of Safety Research, National Institute for Occupational Safety and Health at the time this article was written.

Fall 1988Nolume

19hhmber

3

tations were fingers, and 4% were hands and toes. According to the workers’ compensation data maintained by the Supplementary Data System (SDS), amputations occurred in a wide range of industries and occupations, although the largest percentage of workers injured were machine operators (U.S. Department of Labor, 1983). Machines accounted for the highest percentage of amputation injuries, followed by saws, shears/slicers, and presses. An estimated 192,000 work-related fractures occurred in the United States in 1983. This estimate is based on national projections made from SDS data (U.S. Department of Labor, 1983). Most of these fractures resulted from being struck by a falling object (18%), being struck by an unspecified object (13%), falling on a working surface 103

(16%), and falling from an elevation (17%). Fingers, toes, and feet (excluding toes) were the most common body parts injured. A wide range of occupations reported fracture injuries, with truck drivers, construction laborers, machinists, and operatives accounting for the highest percentages of injured workers. Approximately 30% of all fractures at work specified the source of injury as being floors, the ground, or highway vehicles. Because the risk of injury varies with age (Root, 1981) and sex (Root & Dale): 1980), it is possible to draw biased conclusions when considering these unadjusted data. Standardized morbidity ratios (SMRs) remove differences in the compositions of the populations under study and permit unbiased comparisons with respect to certain variables. In this analysis, SDS and census data were used to calculate SMRs for amputations and fractures by occupation in 30 states. SMRs greater than 100 were then ranked within each state to identify occupations with a high risk of amputation or fracture injuries.

METHOD

Data Source The SDS workers’ compensation data used in this analysis comprise all files on medical treatment cases, cases involving disability, and closed cases. These data are derived from first reports of injuries or illnesses submitted by employers and insurance carriers to state workers’ compensation agencies. The reports include the age, sex, and nature of injury for the injured worker. Federal and self-employed workers, who are not covered by the workers’ compensation claim system, were excluded from the analysis. The SDS has some limitations that must be recognized when analyzing the data (Root & McCaffrey, 1978). First of all, not all of the 50 states participate in the SDS; no more than 33 states have been included since the data collection began in 1976. Also, because states vary in their reporting requirements for a compensable case (e.g., 1 104

to 8 lost workdays), it is difficult to compare data among states or make national statistical inferences. The census data used in the analysis were from the 1980 5% Public-Use Microdata Sample (Bureau of Census, 1983). Calculating

an SMR

An SMR is calculated as 100 times the ratio of the number of injuries observed in each occupation to the number of injuries expected if those employees had the same injury rate as the standard employed population in that state (Monson, 1980). The numerator for the SMR includes all SDS claims filed for amputations or fractures by workers in a specific occupation in each of the 30 participating states from 1979 to 1981. For the denominator, the number of claims expected is the summation of age- and sexspecific amputation or fracture rates for all occupations combined multiplied by the number of employees in each age-sex group in a specific occupation. The census data for each state were used to calculate the ageand sex-specific amputation and fracture rates and the number of employees in occupation age-sex groups. SMRs greater than 100 are due to the number of claims for fracture or amputation injuries exceeding the expected number of claims. Workers in occupations with SMRs greater than 100 are at a higher risk of amputation or fracture than the standard employee population in that state. Using this method of standardization, occupational groups can be ranked according to their SMRs. This ranking provides a comparison, adjusted for age and gender, of the estimated relative risk of amputations or fractures among occupational groups. The SMRs calculated in this analysis will be used to identify occupations in each of the 30 states with higher than expected rates of fractures and amputation injuries. Also calculated is the proportion of states in which an occupational group has a high estimated relative risk of amputation or fracture. Person-years of employment are used to take into account the number of persons employed as well as the duration of their employment. Journal of Safety Research

RESULTS

The occupations with a higher than expected risk of amputation (SMR> 100) are shown in Table 1. SMRs range from 102 (laborers in Arizona) to 1,794 (mine operators in Mississippi). Thus, laborers in Arizona had 1.02 times as many claims filed for amputations as would be expected based on the standard employed population, and mine operators in Mississippi had 17.94 times as many claims filed for amputations as would be expected. A total of 11 occupations had SMRs greater than 100 in the 30 states. Mine operators had the highest SMR for amputations in Alaska, California, Mississippi, Montana, and Wyoming. Machinists ranked first in Arizona, Maryland, New Jersey, and Virginia; laborers in New Mexico, South Dakota, and Vermont; and heavy equipment operators in Colorado, Delaware, Hawaii, Iowa, New York, and Tennessee. Plumbers had the highest SMR in Indiana, Kentucky, Michigan, Oregon, Washington, and Wisconsin. Idaho is the only state in which food service employees had the highest risk of amputation. Material handlers were ranked first only in Nebraska, and firefighters only in North Carolina. In Minnesota, only one occupational group (operatives) had an SMR greater than 100. No occupational groups had SMRs greater than 100 in Maine and Utah. This may be due to the small number of workers with these injuries. Table 2 shows the occupations with a higher than expected risk of fractures (SMR> 100). SMRs range from 102 (food service workers in New Jersey) to 47,000 (firefighters in Kentucky). Thus, food service workers in New Jersey had 1.02 times as many claims filed for fractures as would be expected based on the standard employed population, whereas firefighters in Kentucky had 470 times as many claims filed for fractures as would be expected. A total of 16 occupations had SMRs greater than 100 in the 30 states. Of these, four occupational groups ranked as the highest in the various states. Plumbers had the highest SMR in 14 (47%) of the states: Delaware, Idaho, Indiana, Iowa, Michigan, MinnesoFall 1988Nolume

19Aiumber

3

ta, Montana, New Mexico, Oregon, Tennessee, Utah, Vermont, Washington, and Wyoming. Firefighters had the highest SMR in 12 (40%) states: Arizona, Colorado, Hawaii, Kentucky, Maine, Maryland, Nebraska, New Jersey, New York, North Carolina, Virginia, and Wisconsin. Mine operators had the highest SMR in three (10%) of the states: Alaska, California, and Mississippi. Food service workers ranked highest in only one state, South Dakota. In Table 3, occupational groups are ranked according to the percentage of states in which they had SMRs greater than 100 for amputations. The range is from 73.3% for machinists to 3.3% for firefighters and meat cutters. Machinists and heavy equipment mechanics had SMRs greater than 100 in at least 46% of the states, and mine operators, plumbers, and laborers had SMRs greater than 100 in at least 20% of the states. Table 4 shows occupational groups ranked according to the percentage of states in which they had SMRs greater than 100 for fractures. The range is from 100% for plumbers to 3.3% for cutting operators and road machine operators. In over 75% of the states, plumbers and food service workers had SMRs greater than 100. Over 50% of the states rank material handler, firefighter, laborer, or heavy equipment mechanic as occupations with a high estimated relative risk of fractures. When both SMR ranking and the number of states in which an occupation has an SMR greater than 100 are considered, heavy equipment mechanics and machinists are singled out as having more amputations than expected. Firefighters and plumbers have more fractures than expected.

DISCUSSION

Standardized morbidity ratios can be very useful for showing injury patterns. They provide information on the estimated relative risk of injuries for an occupation by removing the confounding effects of age and sex in employee populations. Thus, these results provide more specific information than other data sources. such as the Bureau of 105

TABLE 1 OCCUPATIONS WITH SMRS> 100 FOR AMPUTATIONS BASED ON SDS DATA FROM 30 STATES, 1979-1981

100

Chi.Sb DCS”

Alaska

Dcclprtlm

616 637 or 639

Mine operator Machinist

Arizona

637 639 686 889

Machinist Meat cutter Laborer

California

616 516 637 or 639

Colorado

sm

observed

clalmsC

Expected

person; pars

1.316 201

10

140 106 IO2

42 19 56

30 18 55

149 70 297

Mine operator Heavy equipment mechanic Machinist

1,095 161 107

12 34 133

1 21 124

12 143 1,062

516 637 or 639 769 616

Heavy equipment mechanic Machinist Cutting operator Mine operator

198 135 132 122

36 54 19 34

18 40 14 28

64 157 46 98

Delaware

516 637 or 639

Heavy equipment mechanic Machinist

146 143

6 18

4 13

11 21

Hawaii

516 637 or 639

Heavy equipment mechanic Machinist

418 328

11 a

3 2

18 12

Idaho

208 637 or 639

Food service Machinist

233 141

5 22

2 16

32

Indiana

557 637 or 639 516

Plunber Machinist Heavy equipment mechanic

618 387 114

13 417 45

2 108 39

9 436 124

Iowa

516 637 or 639

Heavy equipment mechanic Machinist

250 177

26 65

10 37

64 171

Kentucky

557 208 637 or 639

Plumber Food service Machinist

733 280 189

11 25 105

2 9 56

6 47 172

Maine

No SMRs >lOO

Maryland

637 or 639 516

Machinist Heavy equipment mechanic

189 104

53 18

28 17

184 82

Michigan

557 637 or 639 516 616 769

Plunber Machinist Heavy equipment mechanic Mine operator Cutting operator

1,251 488 319 198 137

19 344 69 9 50

2 70 22 5 36

13 587 154 20 253

Minnesota

779

Operative

144

29

20

570

Mississippi

616 637 or 639 889

Mine operator Machinist Laborer

1,794 247 125

26 67 121

1 27 97

74 60 237

106

6

journal

7

of Safety Research

TABLE

1

[CONTINUED]

373

21

6

19

130

13 31

10 24

25 80

43 47

15 45

359 1,203

38 32

29 29

123 116

48 13 258

15 4 102

173 25 944

111

5 101 313 80

0 23 83 72

1 71 280 221

344 344 284 198 139 108

8 19 34 66 24 21

2 6 12 33 17 19

6 26 45 137 56 62

104

23

22

29

Machinist

383 331

80 245

21 74

65 264

Laborer

193

31

16

46

157 150

82 48

52 32

255 142

224 178 148

8 25 209

4 14 141

15 44 483

Machinist

390 158 152 148

11 44 337 209

3 28 222 141

10 77 814 483

Mine

361

117

32

58

Montana

616

Mine

Nebraska

859

Material

637 or 639

Machinist

128

637

Machinist

295

Operative

105

New Jersey

or 639

779

New Rexico

New York

North

Carolina

Oregon

Laborer

133

616

Mine

109

516

Heavy

557

Pluaber

270

637 or 639

Machinist

253

417

Firefighter

516

Heavy

Tennessee

Material

557

Plmaber

208

Food

Material Heavy

769

Cutting

889

Laborer

Venaont

889

Virginia

637

same count

rate

the nuaber

Fall 1988Nolume

equipment

Heavy

557

Plumber

208

Food

637 or 639

Machinist

557

Plmaber

516

Heavy

System

of claims as

mechanic

mechanic

equipment

mechanic

service

equipment

mechanic

Laborer or 639

Classification

of filing

handler

Machinist

or 639

616

'Nwaber

378

operator

516

889

1979-1981.

433

handler

equipment

Heavy or 639

No SMRs > 100

aOccupational

mechanic

Machinist

or 639

Utah

Yymaing

325

service

516

637

mechanic

1,197

equipment

Machinist

516

Yisconsin

equipment

637 or 639

637

Uashington

operator

859

637

Dakota

handler

889

859

South

operator

the

of Persons

code.

expected

total

1 S/Number

3

b

Yorkers'

to be filed

labor

employed

operator

force

and

their

conpensation

if each

(numbers duration

age

rounded

claims

received

and

sex group

to

whole

by

SDS from

in the doccupational

numbers).

Person-years

the

state

group take

for

had

the

into

ac-

of employment.

107

TABLE 2 OCCUPATIONS WITH SMRS > 100 FOR FRACTURES BASED ON SDS DATA FROM 30 STATES, 1979-1981

100 Clai.sb state

Alaska

clCsa

Colorado

Delaware

Hawaii

persmFi years

operator

2,207

140

6

2

Food

Service

2,202

22

1 1

2

417

Fireffghter

1,675

12

557

Plunber

700

4

I

43

13

1

Lunbennan

259

28 111

Machinist

228

41

18

5

779

Operative

129

70

54

13

859

Material

119

34

29

6

417

Firefighter

1,140

41

4

3

557

Plunber

637

94

15

10

859

Materfal

38

616

Mine

889

Laborer

496

Lunberman

516

Heavy

597

Structural

or 639

handler

handler

operator

equipment

mechanic

metal

operator

158

91

58

152

174

114

78

133

528

397

297

116

21

18

9

109

115

106

66

104

67

64

38

616

Mfne

3.086

394

13

12

417

Firefighter

1.455

204

20

16

557

Pltmrber

1.213

273

23

18

496

Lmbetman

962

142

15

6

a59

Materfal

229

651

284

123

516

Heavy

122

424

348

143

417

Flreffghter

557

Plunber

859

Material

208

Food

Service

208

616

Mine

operator

181

516

Heavy

869

Construction

handler

equfpment

mechanic

handler

equfpment

9.917

61

1

1

391

111 317 128 403 240 747

28

12

119 62 223 149 673

54

25 33 19

3 19 12

28 48 70 65 91 51 41

8 19 28 44 46 38

50 11 257 42 191 297 128 720

7 6 154 27 129 211 92 610

266

mechanic

laborer

161 111

557

Plunber

516

Heavy

208

Food

417

Ffrefighter

557

Plunber

639

Food

370

637

108

WC--l

Mine

208

Idaho

Observed

208

637

California

sm

616

496

Arizona

Occl#latllM

ClaimsC

or 639

926

equipment

mechanfc

Service

163 2,375

Service

234

Machinfst

516

Heavy

a59

Material

597

Structural

171

equipment

mechanic

206

handler

112

metal

107

557

Plunber

719

417

Ffreffghter

174

637 or 639

Machinist

167

208

food

859

Materfal

service

496

Lunbennan

516

Heavy

889

Laborer

154

148

handler

equipment

141 mechanic

139 118

1

31 98 64 321 2 11 7 1 3 9 11 18 10 14 2 2 32 7 27 44 23 137

Journal of Safety Research

TABLE

2

(CONTINUED)

100 state

Indiana

Iowa

Kentucky

Maine

Maryland

Michigan

Minnesota

Fall 1988Nolume

Clai.sb

Ocsa

Occlpati m

557 637 or 639 889 208 859

140

110 107 1,072 428 185 170 123 114 109 107

67 332 85 175 145 432 53 280

6 78 46 103 118 379 49 262

5 52 26 64 71 260 33 171

47.000 1,000 269 158 125

75 100 165 620 1.368

0 10 61 392 1.094

1 6 46 172 501

1.895 732 185 159 136 107 105

52 64 62 73 232 673 267

3 9 34 46 171 629 254

1 4 13 9 41 158 59

6,392 881 179 141 105

204 94 240 210 688

3 11 134 149 655

3 9 77 82 391

2,914 2.491 337 272 257 245 220 211 171 140 125

324 102 544 1,606 226 62 256 580 161 742 1.264

11 4 161 590 88 25 116 275 94 530 1,011

13 4 154 587 80 20 123 267 87 523 1.033

875 161

41 453

5 281

11 645

270

service handler

Plumber handler

Structural Heavy

metal

equipment

mechanic

Road machine

operator

Construction

laborer

Food

service

Machinist Firefighter Pluaber Food

service

Machinist Laborer Firefighter Plumber Food

service

Structural Material

metal handler

Laborer Construction

417 557 859 516 869

laborer

Firefighter Plmaber Material Heavy

handler

equipment

Construction

557 417 516 637 or 639 597 616 208 859 808 869 889

mechanic

laborer

Plumber Firefighter Heavy

equipment

mechanic

Machinist Structural

metal

Mine

operator

Food

service

Material

handler

Bus driver Construction Laborer

557 889

19hhmber

Laborer

Material

417 557 208 597 859 889 869

Plumber Laborer

3

wcw

Food

1,890

Material

417 557 208 637 or 639 889

obsened

persmz plrs

176 1,694 1.984 149 386

Pluaber Machinist

557 859 597 516 844 869 208 637 or 639

mrl

Clai.sC

laborer

9 627 1,417 135 361

10 436 1.017 92 242

109

TABLE 2 (CONTINUED)

100

state

Mississippi

Montana

Nebraska

New Jersey

New

New

Mexico

York

OCsa

110

Expcca

persrn2 pars

7

Mine

2,736

216

8

557

Plunber

614

32

5

4

889

Laborer

149

802

538

237

637 or 639

Machinist

120

184

153

60

operator

557

Pluaber

616

Mine

779 208 769

Cutting

417

Firefighter

557

Pluaber

1.400

70

5

2

313

311

99

19

Operative

145

189

130

24

Food

136

41

30

8

108

32

30

4

5,057

47

1

1

726

73

10

4

operator service operator

859

Material

233

211

91

25

637 or 639

Machinist

128

373

291

80

208

Food

120

65

54

15

889

Laborer

107

1.098

1,026

309

417

Firefighter

24,000

37

0

1

557

Plumber

1.275

104

8

14

689

Laborer

171

545

319

526

637 or 639

Machinist

171

391

229

359

859

Material

141

126

89

139

869

Construction

122

201

165

247

597

Structural

117

41

35

42

516

Heavy

106

57

54

66

208

Food

102

39

38

55

handler

service

handler laborer metal

equipment

mechanic

service

557

Plumber

611

24

4

3

889

Laborer

171

317

185

123

616

Mine

operator

130

241

185

116

208

Food

service

123

17

14

12

597

Structural

104

30

29

13

417

Firefighter

3,961

426

11

6

557

Plusher

1.166

490

41

25 300

metal

859

Material

166

1.020

543

616

Mine

operator

184

55

30

16

208

Food

service

158

561

355

210

516

Heavy

889

Laborer

handler

equipment

Structural

597

Carolina

slut

Clai.sC

616

637

North

Occlpatim

Clai.sb Observed

or 639

mechanic

metal

Machinist

869

Construction

417

Firefighter

557

Plumber

516

Heavy

637 or 639

Machinist

laborer

equipment

208

Food

659

Material

597

Structural

mechanic

152

514

338

173

152

3.504

2,305

1.314

139

232

167

82

124

2,148

1,732

944

107

1,523

1,423

771

21,000

108

1

1

1.202

194

16

9

352

689

196

71

186

1,391

748

280

160

262

164

63

handler

150

865

577

221

metal

135

143

106

34

service

Journal of Safety Research

TABLE 2 (CONTINUED)

100 Oc2

Ocupa ti m

mR

C1ai.sb ObseIved

Oregon

557 859 417 516 637 or 639 597 208 496 889

Plunber Material handler Firefighter Heavy equipment mechanic Machinist Structural metal Food service Lunbennan Laborer

626 559 387 194 158 137 120 103 103

81 511 35 248 476 78 63 648 941

13 91 9 128 301 57 53 629 914

6 45 3 56 137 22 25 290 438

South Dakota

208 859 557 889 516

Food service Material handler Pluaber Laborer Heavy equipment mechanic

1,431 779 346 219 210

122 77 21 1,326 94

9 10 6 605 45

1 1 1 29 4

Tennessee

557 417 516 637 or 639 859 889 597

Pluaber Firefighter Heavy equipment mechantc Machinist Material handler Laborer Structural metal

2.192 385 232 165 135 122 109

85 13 238 639 289 1,392 82

4 3 103 387 214 1,141 75

4 2 65 264 143 831 43

Utah

557 417 208

Pluaber Firefighter Food service

2,789 1.918 137

69 15 45

2 1 33

1 1 18

Vermont

557 889 208

Plumber Laborer Food service

1.275 268 216

36 469 29

3 175 13

3 46 3

Virginia

417 557 859 616 597 516

Firefighter Plumber Material handler Mine operator Structural metal Heavy equipment mechanic

2.150 929 136 120 119 118

68 93 250 324 107 264

3 10 184 270 90 224

3 12 119 173 53 142

Washington

557 859 889 208 597 637 or 639

Plmnber Material handler Laborer Food service Structural metal Machinist

799 250 171 141 132 128

313 508 3,028 193 283 1.419

39 203 1,802 137 214 1.109

15 60 567 44 59 336

Wisconsin

417 557 616 889 516 208 869

Firefighter Pluaber Mine operator Laborer Heavy equipment mechanfc Food servfce Construction laborer

8.089 824 193 169 167 128 124

90 109 12 2,807 299 165 719

1 13 6 1,661 179 129 580

2 10 3 814 77 60 266

state

Fall 1988Nolume

1 S/Number

3

claf.sC WC-d

r-m; scaly

111

TABLE 2 (CONTINUED)

100 state

Uyaning

occupatim

ocsa

557 616 808 208

SUR

Plmnber Mine operator Bus driver Food service

457 417 270 125

ClailBsb observed

person;

Cltii.SC

yeprs

Expect-J

85 1,941 15 18

19 465 6 14

4 58 2 2

b aOccupationalClassification System code. Workers' canpensatlon claims received by SDS fran the state for 1979-1981. 'Nunber of claims expected to be filed if each age and sex group in the doccupatlonal group had the same rate of filing as the total labor force (nmabers rounded to whole nunbers). Person-years take into account the number of persons employed and their duration of emploment.

Labor Statistics’ Annual Survey, which do not adjust for age and sex when calculating injury rates. Moreover, by identifying occupations with higher estimated relative risk of amputations and fractures in various states, rather than in the entire country, these data provide a more defined target area for research and intervention.

TABLE 4 OCCUPATIONS RANKED BY PERCENTAGE OF STATES IN WHICH THEY HAVE SMR > 100 FOR FRACTURES. 1979-1981

2

with OCS”

TABLE 3 OCCUPATIONS RANKED BY PERCENTAGE OF SIATES IN WHICH THEY HAVE SMR > 100 FOR AMPUTATIONS,

OCS”

637 or 639 516 616 557 889 208 769 859 779 417 686

1979-1981

tkuprtim

Machinist Heavy equipment mechanic Mine operator Plunber Laborer Food service Cutting operator Material handler Operative Firefighter Meat cutter

'Occupati~al ClassificationSystem code.

112

I of states wfth SWR> 100

73.3 46.7 26.7 23.3 20.0 13.3 10.0 10.0 6.7 3.3 3.3

of states

557 208 859 417 889 516 637 or 639 597 616 869 496 808 779 769 844

Oc*ati

an

SWR> 100

Plumber Food service Material handler Firefighter Laborer Heavy equfpment mechanic Machinist Structural metal Nine operator Construction laborer Lunbennan Bus driver Operative Cutting operator Road machine operator

100.0 76.7 66.7 63.3 60.0 56.7 46.7 43.3 40.0 26.7 16.7 6.7 6.7 3.3 3.3

'Occupational Classification System code.

REFERENCES Bureau of Census. (1983). Census of populat~ofl and housing, 1380: Public-use microdata sampk. Washington, DC: U.S. Department of Commerce. Centers for Disease Control, National Institute for Occupational Safety and Health (NIOSH). (1983). Leading work-related diseases and injuriesUnited

Journal

of Safety Research

States. Morbidity and ~ortal~~~ Weekly Report, 32(14), 190. Monson, R. (1980). Occupational epidemiology. Boca Raton, FL: CRC Press. NIOSH, Division of Safety Research. (1984). Severe occupational traumatic injuries. ~or~~~~~~ and Mortal&f Weekly Report, 33(16). Root, N. (1981). Injuries at work are fewer among older employees. Monthly Labor Review, 104(3), 30-34.

Fall 198~~5lume

19~~rnbe~ 3

Root, N., & Daley, J. R. (1980). Are women safer workers? A new look at the data. Monthly Labor Review, 103(9), 3-10. Root, N., & McCaffrey, D. (1978). Providing more information on work injury and illness. Monthly Labor Review, 10f(4), 16-21. United States Department of Labor, Bureau of Labor Statistics. (1983). Supplementary data system microdata f&v. Washington, DC: Author.

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