Longitudinal Study of Silica Dust

Longitudinal Study of
Occupational Exposure
to Silica Dust (1984-2013)
Presented by:
Bernard L. Fontaine, Jr., CIH, CSP, FAIHA
The Windsor Consulting Group, Inc.

Occupational Exposure to Silica
Dust (1984-2013)
 OSHA authoritative health hazard database
within the jurisdiction of covered industries
 Examined total of 53,684 sampling records
 Sampling performed by OSHA personnel
 Testing followed OSHA validated sampling
and analytical method
 Analysis by the OSHA’s AIHA accredited lab

Dust (1984-2013)
 Respirable dust loading sample records >1
mg/m3 were removed from the database
 Duplicate records removed along with non-
respirable/amorphous silica sampling data
 Sampling data sorted by Standard Industrial
Code (SIC) – Division and Major Group
 No information given on silica polymorphs –
quartz, cristobalite, tridymite or interference

Dust (1984-2013)
 Total number of bulk dust samples – 7,748
 Total number of personal and area short-term
or full-shift samples – 23,270
 OSHA PEL calculated based on percent silica
in bulk dust samples
 8-hour TWA calculated based on amount of
silica in each sample and collection time

Dust (1984-2013)
 Calculated sample results compared to
ACGIH TLV of 0.025 mg/m3 and NIOSH REL
of 0.050 mg/m3 as 8-hour TWA
 Relative risk estimated on percent of sample
results with silica above the ACGIH TLV and
NIOSH REL
 Proposed change to OSHA PEL as 0.050
mg/m3 as 8-hour TWA

OSHA Inspection Sample Data (1974 – 1994)

Agency
1979-1984 1985-1994
Total Air Samples Samples > OSHA PEL Total Air Samples Samples > OSHA PEL
Number Average
Severity
Percent
(%)
Average
Severity
Number Average
Severity
Percent
(%)
Average
Severity
MSHA 79,615 0.89 16.9 3.87 139,423 0.67 14.7 3.14
OSHA 7,911 2.49 27.2 8.25 7,392 2.67 21.2 11.73
Number of MSHA and OSHA Inspector Silica Samples
And Percent Exceeding the Permissible Exposure Limit, 1974-1994

0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0 2500 5000 7500 10000 12500 15000 17500 20000 22500
8-HourTWA(mg/m3)
Number of Samples
OSHA Crystalline Silica Dust (1984-2013)
ACGIH TLV-TWA
0.025 mg/m3

32.9%
57.3%
27.7%
36.7%
20.4%
33.3%
29.1%
16.3%
35.0%
22.9%
Bulk Dust Sample SiO2 (%)
Agriculture, Forestry
Mining
Construction
Manufacturing
Trans/Com Elec/Gas
Wholesale Trade
Retail Trade
Finance/Insurance
Services
Public Administration

7%
13%
10%
9%
9%
13%
13%
5%
13%
8%
Personal/Area Sample SiO2 (%)
Mining
Construction
Manufacturing
Trans/Com Elec/Gas
Wholesale Trade
Retail Trade
Finance/Insurance
Services

22
69
3,984
18,488
168
188 22
20
251
58
Personal/Area Samples
Mining
Construction
Manufacturing
Trans/Com Elec/Gas
Wholesale Trade
Retail Trade
Finance/Insurance
Services

0.000
0.005
0.010
0.015
0.020
0.025
0.030
0.035
Average Exposure to Crystalline Silica
Dust
CI (95%) Median Mean

Division Industry Samples Bulk SiO2 (%)
Sample
SiO2 (%)
Mean Median Variance STD CI (95%)
ACGIH
TLV↑
NIOSH
REL↑
Division A
Agriculture,
Forestry, and
Fishing
22 32.9% 9.5% 0.029 0.028 0.000 0.019 0.008 63.6% 18.2%
Division B Mining 69 57.3% 18.2% 0.012 0.008 0.000 0.016 0.004 8.7% 2.9%
Division C Construction 3984 27.7% 14.9% 0.024 0.016 0.001 0.025 0.001 32.6% 11.2%
Division D Manufacturing 18488 36.7% 13.2% 0.024 0.016 0.001 0.029 0.000 31.0% 10.2%
Division E
Transportation/
Communication,
Elec/Gas
168 20.4% 12.1% 0.033 0.018 0.003 0.052 0.008 41.1% 19.0%
Division F Wholesale Trade 188 33.3% 19.0% 0.025 0.019 0.001 0.023 0.003 38.3% 14.4%
Division G Retail Trade 22 29.1% 18.3% 0.025 0.013 0.001 0.035 0.015 27.3% 13.6%
Division H
Finance ,
Insurance, and
Real Estate
20 16.3% 7.6% 0.023 0.012 0.000 0.022 0.010 45.0% 10.0%
Division I Services 251 35.0% 19.2% 0.023 0.013 0.001 0.034 0.003 23.9% 12.4%
Division J
Public
Administration
58 22.9% 11.6% 0.019 0.013 0.000 0.018 0.005 22.4% 6.9%
Summary 23270 31.2% 14.4% 0.024 0.016 0.000 0.018 0.005 31.3% 10.5%

0.0%
10.0%
20.0%
30.0%
40.0%
50.0%
60.0%
70.0%
Percent of Air Samples Above ACGIH TLV and NIOSH REL
ACGIH TLV↑ NIOSH REL↑

0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
8-HourTWA
Number of Samples
Division A - Agriculture, Forestry, and Fishing
Samples Bulk SiO2 (%) Sample SiO2 % Mean Median Variance STD CI (95%) ACGIH TLV↑
22 32.9% 9.5% 0.029 0.028 0.000 0.019 0.008 63.6%

Division A: Agriculture, Forestry, and Fishing
Major Group Classification Samples Bulk SiO2 (%) Sample SiO2 % Mean Median Variance STD CI (95%) ACGIH TLV↑
1
Ag. Production
Crops
1 10.0% 8.10% 0.014 0.014 0.0%
7
Agricultural
Services
19 20.0% 8.9% 0.033 0.031 0.000 0.016 0.007 73.7%
8 Forestry 2 70.0% 15.0% 0.014 0.014 0.000 0.003 0.004 0.0%
Industry Group Div. A: Major Group 1 Industries
11 Cash Grains
13 Field Crops, Except Cash Grains
16 Vegetables And Melons
17 Fruits And Tree Nuts
18 Horticultural Specialties
19 General Farms, Primarily Crop
71 Soil Preparation Services
72 Crop Services
74 Veterinary Services
75 Animal Services, Except Veterinary
76 Farm Labor And Management Services
78 Landscape And Horticultural Services
81 Timber Tracts
83 Forest Nurseries And Gathering Of Forest
85 Forestry Services
Relative Risk Risk Category
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
8-HourTWA
Number of Samples
Division B - Mining
69 57.3% 18.2% 0.012 0.008 0.000 0.016 0.004 8.7%

Division B: Mining
12 Coal Mining 1 4.0% 1.0% 0.012 0.012 0.0%
13
Oil and Gas
Extraction
42 76.7% 22.1% 0.011 0.006 0.000 0.020 0.006 9.5%
14
Mine/Quarry
Nonmetals, and
Minerals
25 27.5% 12.6% 0.019 0.017 0.000 0.011 0.004 28.0%
Industry Group Div. B: Major Group 12 Industries
122 Bituminous Coal And Lignite Mining
123 Anthracite Mining
124 Coal Mining Services
131 Crude Petroleum And Natural Gas
132 Natural Gas Liquids
138 Oil And Gas Field Services
141 Dimension Stone
142 Crushed And Broken Stone, Including Riprap
144 Sand And Gravel
145 Clay, Ceramic, And Refractory Minerals
147 Chemical And Fertilizer Mineral Mining
148 Nonmetallic Minerals Services, Except Fuels
149 Miscellaneous Nonmetallic Minerals, Except
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

3984 27.7% 14.9% 0.024 0.016 0.001 0.025 0.001 32.6%

Division C: Construction
15
Buildings: GCs and
General Operative
Builders
469 24.3% 12.6% 0.023 0.017 0.000 0.020 0.002 32.8%
16
Heavy
Construction other
than Builders
991 26.3% 16.0% 0.027 0.019 0.001 0.028 0.002 38.7%
17
Special Trade
Contractors
2524 29.0% 15.0% 0.023 0.015 0.001 0.024 0.001 30.1%
Industry Group Div. C: Major Group 15 Industries
152 General Building Contractors-Residential
153 Operative Builders
154 General Building Contractors-Nonresidential
161 Highway and Street Construction
162
Heavy Construction, Except Highway
and Street
171 Plumbing, HVAC
172 Painting And Paper Hanging
173 Electrical Work
174 Masonry, Stone, Tile, and Plaster
175 Carpentry And Floor Work
176 Roofing, Siding, and Sheet Metal
177 Concrete Work
178 Water Well Drilling
179 Misc. Special Trade Contractors
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

Number and Percent of Time-Weighted Average
(TWA) Exposure Respirable Silica Samples for
Construction and General Industry,
Compared to the OSHA PEL
Construction Industry Other than Construction
Occupational Exposure
Relative to the OSHA PEL
No. of
samples
Percent
Risk
Potential
No. of
samples
Percent
Risk
Potential
<1 PEL 972 66% Low 3,174 67% Low
1 x PEL to < 2 x PEL 135 9% Very High 576 12% Very High
2 x PEL to < 3 x PEL 80 5% Urgent 261 6% Urgent
≥ 3 x PEL and
higher(3+)
283 19% Intolerable 707 15% Intolerable
Total # of Air Samples 1,470 4,718
Source: Unpublished data maintained by the OSHA Integrated Management Information System (IMIS)* from January 1, 1997 to
December 31, 2009.

18488 36.7% 13.2% 0.024 0.016 0.001 0.029 0.000 31.0%

Division D: Manufacturing
20
Food/Kindred
Products
31 9.6% 5.2% 0.054 0.029 0.004 0.067 0.024 58.1%
22
Textile Mill
Product
10 10.5% 17.3% 0.067 0.071 0.001 0.032 0.020 90.0%
23
Apparel and Other
Finished Fabric
11 10.0% 6.4% 0.023 0.013 0.001 0.026 0.015 27.3%
24
Lumber and Wood
Products, Except
Furniture
75 23.3% 11.4% 0.031 0.016 0.001 0.039 0.009 34.7%
25
Furniture and
Fixtures
22 26.8% 17.0% 0.028 0.019 0.001 0.032 0.013 31.8%
26
Paper and Allied
Products
19 9.9% 3.7% 0.017 0.011 0.000 0.015 0.007 26.3%
28
Chemicals and
Allied Products
355 35.6% 15.8% 0.021 0.009 0.001 0.034 0.004 22.5%
29
Petroleum Refining
and Related
Industries
93 41.6% 18.5% 0.022 0.015 0.001 0.024 0.005 26.9%
30
Rubber and
Miscellaneous
Plastic Products
170 23.5% 10.6% 0.024 0.015 0.001 0.031 0.005 35.9%
31
Leather and Leather
Products
2 1.1% 1.6% 0.017 0.017 0.000 0.008 0.011 0.0%
32
Stone, Clay, Glass,
and Concrete
Products
5950 27.5% 13.1% 0.028 0.021 0.001 0.028 0.001 42.5%

Division D: Manufacturing
33
Primary Metal
Industries
9361 44.0% 11.6% 0.020 0.013 0.001 0.025 0.001 23.0%
34
Fabricated Metal
Products, Except
Machinery and
Transportation
Equipment
1127 43.5% 23.4% 0.027 0.016 0.001 0.036 0.002 34.2%
35
Industrial and
Commercial
Machinery and
Computer
Equipment
594 50.1% 14.4% 0.024 0.015 0.001 0.033 0.003 28.1%
36
Electronic and
Other Electrical
Equipment and
Components,
Except Computers
157 49.2% 16.3% 0.034 0.018 0.003 0.056 0.009 36.9%
37
Transportation
Equipment
279 44.8% 20.8% 0.023 0.015 0.001 0.028 0.003 33.0%
38
Measuring,
Analyzing, and
Controlling
Instruments;
Photographic,
Medical, and
Optical Goods
119 26.6% 17.9% 0.038 0.022 0.004 0.066 0.012 44.5%
39
Miscellaneous
Manufacturing
Industries
115 33.6% 20.6% 0.044 0.025 0.002 0.048 0.009 52.2%

Industry Group Div. D: Major Group 20 Industries
201 Meat Products
202 Dairy Products
203 Canned, Frozen, And Preserved Fruits, Vegetables, and Food Specialties
204 Grain Mill Products
205 Bakery Products
206 Sugar And Confectionery Products
207 Fats And Oils
208 Beverages
209 Miscellaneous Food Preparations And Kindred
211 Cigarettes
212 Cigars
213 Chewing And Smoking Tobacco And Snuff
214 Tobacco Stemming And Redrying
221 Broadwoven Fabric Mills, Cotton
222 Broadwoven Fabric Mills, Manmade Fiber And Silk
223 Broadwoven Fabric Mills, Wool
224 Narrow Fabric and Other Smallwares Mills, Cotton, Wool, Silk, and Manmade Fiber
225 Knitting Mills
226 Dyeing and Finishing Textiles, Except Wool Fabrics
227 Carpets and Rugs
228 Yarn and Thread Mills
229 Miscellaneous Textile Goods

231 Men's And Boys' Suits, Coats, And Overcoats
232 Men's And Boys' Furnishings, Work Clothing, And Allied Garments
233 Women's, Misses', And Juniors' Outerwear
234 Women's, Misses', Children's, And Infants'
235 Hats, Caps, And Millinery
236 Girls', Children's, And Infants' Outerwear
237 Fur Goods
238 Miscellaneous Apparel And Accessories
239 Miscellaneous Fabricated Textile Products
241 Logging
242 Sawmills And Planning Mills
243 Millwork, Veneer, Plywood, And Structural Wood
244 Wood Containers
245 Wood Buildings And Mobile Homes
249 Miscellaneous Wood Products
251 Household Furniture
252 Office Furniture
253 Public Building and Related Furniture
254 Partitions, Shelving, Lockers
259 Miscellaneous Furniture And Fixtures

261 Pulp Mills
262 Paper Mills
263 Paperboard Mills
265 Paperboard Containers And Boxes
267 Converted Paper and Paperboard Products
271 Newspapers: Publishing, Or Publishing And Printing
272 Periodicals: Publishing, Or Publishing And Printing
273 Books
274 Miscellaneous Publishing
275 Commercial Printing
276 Manifold Business Forms
277 Greeting Cards
278 Blankbooks, Looseleaf Binders, and Bookbinding
279 Service Industries for the Printing Trade
281 Industrial Inorganic Chemicals
282 Plastics Materials And Synthetic Resins, Synthetic
283 Drugs
284 Soap, Detergents, Cleaners; Perfumes, Cosmetics, and Other Toilet Preparations
285 Paints, Varnishes, Lacquers, Enamels, And Allied
286 Industrial Organic Chemicals
287 Agricultural Chemicals
289 Miscellaneous Chemical Products

291 Petroleum Refining
295 Asphalt Paving And Roofing Materials
299 Miscellaneous Products Of Petroleum And Coal
301 Tires And Inner Tubes
302 Rubber And Plastics Footwear
305 Gaskets, Packing, And Sealing Devices And Rubber
306 Fabricated Rubber Products, Not Elsewhere
308 Miscellaneous Plastics Products
311 Leather Tanning And Finishing
313 Boot And Shoe Cut Stock And Findings
314 Footwear, Except Rubber
315 Leather Gloves And Mittens
316 Luggage
317 Handbags and Other Personal Leather Goods
319 Leather Goods, Not Elsewhere Classified

321 Flat Glass
322 Glass and Glassware, Pressed or Blown
323 Glass Products, Made Of Purchased Glass
324 Cement, Hydraulic
325 Structural Clay Products
326 Pottery And Related Products
327 Concrete, Gypsum, And Plaster Products
328 Cut Stone And Stone Products
329 Abrasive, Asbestos, and Miscellaneous
331 Steel Works, Blast Furnaces, And Rolling And Finishing Mills
332 Iron and Steel Foundries
333 Primary Smelting and Refining of Nonferrous
334 Secondary Smelting and Refining of Nonferrous
335 Rolling, Drawing, and Extruding of Nonferrous
336 Nonferrous Foundries (Castings)
339 Miscellaneous Primary Metal Products

341 Metal Cans and Shipping Containers
342 Cutlery, Handtools, and General Hardware
343 Heating Equipment, Except Electric and Warm Air
344 Fabricated Structural Metal Products
345 Screw Machine Products, And Bolts, Nuts, Screws, Rivets, and Washers
346 Metal Forgings and Stampings
347 Coating, Engraving, and Allied Services
348 Ordnance and Accessories, Except Vehicles and Guided Missile
349 Miscellaneous Fabricated Metal Products
351 Engines And Turbines
352 Farm And Garden Machinery And Equipment
353 Construction, Mining, and Materials Handling
354 Metalworking Machinery and Equipment
355 Special Industry Machinery, Except Metalworking
356 General Industrial Machinery and Equipment
357 Computer and Office Equipment
358 Refrigeration and Service Industry Machinery
359 Miscellaneous Industrial and Commercial

361 Electric Transmission And Distribution Equipment
362 Electrical Industrial Apparatus
363 Household Appliances
364 Electric Lighting and Wiring Equipment
365 Household Audio and Video Equipment, and Audio
366 Communications Equipment
367 Electronic Components and Accessories
369 Miscellaneous Electrical Machinery, Equipment, and Supplies
371 Motor Vehicles and Motor Vehicle Equipment
372 Aircraft and Parts
373 Ship and Boat Building and Repairing
374 Railroad Equipment
375 Motorcycles, Bicycles, and Parts
376 Guided Missiles and Space Vehicles and Parts
379 Miscellaneous Transportation Equipment
381
Search, Detection, Navigation, Guidance, Aeronautical, and Nautical Systems, Instruments,
and Equipment
382 Laboratory Apparatus And Analytical, Optical, Measuring, and Controlling Instruments
384 Surgical, Medical, and Dental Instruments And Supplies
385 Ophthalmic Goods
386 Photographic Equipment and Supplies
387 Watches, Clocks, Clockwork Operated Devices, and Parts

391 Jewelry, Silverware, and Plated Ware
393 Musical Instruments
394 Dolls, Toys, Games and Sporting and Athletic
395 Pens, Pencils, and Other Artists Materials
396 Costume Jewelry, Costume Novelties, Buttons, And Misc. Notions, Except Precious Metal
399 Miscellaneous Manufacturing Industries
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

168 20.4% 12.1% 0.033 0.018 0.003 0.052 0.008 41.1%

Division E: Transportation, Communications, Electric, Gas, And Sanitary Services
Major
Group
Classification Samples Bulk SiO2 (%) Sample SiO2 % Mean Median Variance STD CI (95%) ACGIH TLV↑
40
Railroad
Transportation
28 32.6% 15.3% 0.028 0.020 0.001 0.025 0.009 42.9%
42
Motor Freight
Transport and
Warehousing
39 25.2% 11.1% 0.028 0.013 0.002 0.044 0.014 28.2%
43
United States
Postal Service
11 16.1% 17.9% 0.050 0.022 0.003 0.052 0.031 45.5%
44
Water
Transportation
15 10.1% 4.3% 0.019 0.005 0.000 0.022 0.011 33.3%
45
Transportation
by Air
2 24.8% 7.5% 0.001 0.001 0.000 0.000 0.001 0.0%
47
Transportation
Services
4 49.6% 45.8% 0.019 0.024 0.000 0.012 0.012 50.0%
49
Electric, Gas,
and Sanitary
Services
69 13.4% 10.7% 0.039 0.024 0.005 0.068 0.016 49.3%
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

Industry Group Div. E: Major Group 40 Industries
401 Railroads
411 Local And Suburban Passenger Transportation
412 Taxicabs
413 Intercity and Rural Bus Transportation
414 Bus Charter Service
415 School Buses
417 Terminal and Service Facilities for Motor Vehicle
421 Trucking And Courier Services, Except Air
422 Public Warehousing And Storage
423 Terminal And Joint Terminal Maintenance
431 United States Postal Service
441 Deep Sea Foreign Transportation of Freight
442 Deep Sea Domestic Transportation of Freight
443 Freight Transportation On The Great Lakes
444 Water Transportation of Freight, Not Elsewhere
448 Water Transportation of Passengers
449 Services Incidental to Water Transportation

451 Air Transportation, Scheduled, and Air Courier
452 Air Transportation, Nonscheduled
458 Airports, Flying Fields, and Airport Terminal
461 Pipelines, Except Natural Gas
472 Arrangement of Passenger Transportation
473 Arrangement of Transportation of Freight and Cargo
474 Rental of Railroad Cars
478 Miscellaneous Services Incidental to Transportation
481 Telephone Communications
482 Telegraph and Other Message Communications
483 Radio and Television Broadcasting Stations
484 Cable and Other Pay Television Services
489 Communications Services, Not Elsewhere

491 Electric Services
492 Gas Production and Distribution
493 Combination Electric And Gas, and Other Utility
494 Water Supply
495 Sanitary Services
496 Steam And Air-Conditioning Supply
497 Irrigation Systems
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

188 33.3% 19.0% 0.025 0.019 0.001 0.023 0.003 38.3%

Division F: Wholesale Trade
50
Wholesale
Trade Durable
Goods
137 42.2% 21.6% 0.025 0.019 0.001 0.023 0.004 38.7%
51
Wholesale
Trade Non-
Durable Goods
51 13.4% 8.3% 0.026 0.018 0.001 0.025 0.007 37.3%
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

Industry Group Div. F: Major Group 50 Industries
501 Motor Vehicles and Motor Vehicle Parts and Supplies
502 Furniture and Home Furnishings
503 Lumber and Other Construction Materials
504 Professional and Commercial Equipment and Supplies
505 Metals and Minerals, Except Petroleum
506 Electrical Goods
507 Hardware, and Plumbing and Heating Equipment
508 Machinery, Equipment, and Supplies
509 Miscellaneous Durable Goods
Industry Group Div. F: Major Group 51 Industries
511 Paper and Paper Products
512 Drugs, Drug Proprietaries, and Druggists' Sundries
513 Apparel, Piece Goods, and Notions
514 Groceries and Related Products
515 Farm-Product Raw Materials
516 Chemicals and Allied Products
517 Petroleum and Petroleum Products
518 Beer, Wine, and Distilled Alcoholic Beverages
519 Miscellaneous Non-durable Goods

22 29.1% 18.3% 0.025 0.013 0.001 0.035 0.015 27.3%

Division G: Retail Trade
52
Building
Materials,
Hardware,
Garden Supply,
Mobile Homes
6 25.0% 12.2% 0.015 0.008 0.000 0.018 0.014 16.7%
53
General
Merchandise
Stores
1 30.5% 6.5% 0.013 0.013 0.0%
54 Food Stores 1 19.0% 100.0% 0.144 0.144 100.0%
55
Auto Dealers
and Gas Service
Stations
56
Apparel and
Accessory Stores
57
Home Furniture,
Furnishings, and
Equip. Stores
58
Eating and
Drinking Places
59
Miscellaneous
Retail
13 23.7% 15.3% 0.022 0.014 0.001 0.027 0.015 23.1%
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

Industry Group Div. G: Major Group 52 Industries
521 Lumber and Other Building Materials Dealers
523 Paint, Glass and Wallpaper Stores
525 Hardware Stores
526 Retail Nurseries, Lawn and Garden Supply Stores
527 Mobile Home Dealers
531 Department Stores
533 Variety Stores
539 Miscellaneous General Merchandise Stores
541 Grocery Stores
542 Meat And Fish (seafood) Markets, Including
543 Fruit And Vegetable Markets
544 Candy, Nut, And Confectionery Stores
545 Dairy Products Stores
546 Retail Bakeries
549 Miscellaneous Food Store
581 Eating and Drinking Places

591 Drug Stores and Proprietary Stores
592 Liquor Stores
593 Used Merchandise Stores
594 Miscellaneous Shopping Goods Stores
596 Nonstore Retailers
598 Fuel Dealers
599 Retail Stores, Not Elsewhere Classified
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

20 16.3% 7.6% 0.023 0.012 0.000 0.022 0.010 45.0%

Division H: Finance, Insurance, and Real Estate
60
Depository
Institutions
61
Non-deposit
Credit
Institutions
62
Security,
Commodity,
Broker, Dealer
Exchange
63
Insurance
Carriers
64
Insurance
Agent, Brokers,
and Service
65 Real Estate 20 16.3% 7.6% 0.023 0.012 0.000 0.022 0.010 45.0%
67
Holding and
Other Invest-
ment Offices
0-20 % Very Low
20-40% Low
40-60% Moderate
60-80% High
80-100% Very High
Uncertain

0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0 25 50 75 100 125 150 175 200 225 250
8-HourTWA
Number of Samples
Division I - Services
251 35.0% 19.2% 0.023 0.013 0.001 0.034 0.003 23.9%

Division I: Services
Major Group Classification Samples
Bulk SiO2
(%)
Sample SiO2
%
Mean Median Variance STD CI (95%) ACGIH TLV↑
70
Hotels, Rooming
Houses, Camps,
And Other Lodging
6 40.0% 19.5% 0.026 0.010 0.001 0.028 0.022 33.3%
72 Personal Services 1 3.8% 1.0% 0.003 0.003 0.0%
73 Business Services 30 29.8% 21.4% 0.037 0.019 0.003 0.053 0.023 40.0%
75
Automotive Repair,
Services, Parking
58 45.1% 24.6% 0.016 0.007 0.001 0.025 0.006 17.2%
76
Miscellaneous
Repair Services
91 40.0% 17.9% 0.019 0.008 0.001 0.033 0.007 16.5%
78 Motion Pictures
79
Amusement and
Recreation Services
4 25.8% 10.0% 0.059 0.033 0.006 0.081 0.079 50.0%
80 Health Services 20 34.6% 16.9% 0.028 0.015 0.001 0.035 0.015 30.0%
81 Legal Services
82
Educational
Services
8 27.5% 9.2% 0.025 0.020 0.000 0.016 0.011 25.0%
83 Social Services 2 24.0% 7.0% 0.020 0.020 0.000 0.003 0.004 0.0%
84
Museums, Art
Gallery, Botanical
and Zoo Gardens
86
Membership
Organizations
87
Engineer, Account,
Research,
Management, and
Related Services
23 21.0% 13.4% 0.024 0.014 0.001 0.031 0.013 30.4%
88 Private Household
89
Miscellaneous
Services
8 28.9% 23.2% 0.030 0.032 0.000 0.010 0.007 62.5%

58 22.9% 11.6% 0.019 0.013 0.000 0.018 0.005 22.4%

Division J: Public Administration
91
Executive,
Legislative, and
General
Government,
Except Finance
92
Justice, Public
Order, and
Safety
93
Public Finance,
Taxation, And
Monetary
Policy
94
Admin. of
Human
Resource
Programs
95
Admin. of
Environmental
Quality and
Housing
14 18.1% 11.9% 0.013 0.009 0.000 0.010 0.005 7.1%
96
Administration
of Economic
Programs
10 28.1% 15.9% 0.023 0.021 0.000 0.011 0.007 30.0%
97
National
Security and
Internat'l
Affairs
34 14.3% 10.1% 0.020 0.013 0.000 0.021 0.007 26.5%
99
Nonclassifiable
Establishments

Pictogram to Illustrate
Relative Risk Determination
Relative
Risk

Division Industry Samples
Bulk SiO2
(%)
Sample SiO2
(%)
Mean Median Variance STD CI (95%)
ACGIH
TLV↑
 75%
ACGIH TLV
Division A
Agriculture,
Forestry, and
Fishing
22 32.9% 9.5% 0.029 0.028 0.000 0.019 0.008 63.6% 68.2%
Division B Mining 69 57.3% 18.2% 0.012 0.008 0.000 0.016 0.004 8.7% 14.5%
Division C Construction 3984 27.7% 14.9% 0.024 0.016 0.001 0.025 0.001 32.6% 45.1%
Division D Manufacturing 18488 36.7% 13.2% 0.024 0.016 0.001 0.029 0.000 31.0% 42.6%
Division E
Transportation/C
ommunication,
Elec/Gas
168 20.4% 12.1% 0.033 0.018 0.003 0.052 0.008 41.1% 49.4%
Division F Wholesale Trade 188 33.3% 19.0% 0.025 0.019 0.001 0.023 0.003 38.3% 51.1%
Division G Retail Trade 22 29.1% 18.3% 0.025 0.013 0.001 0.035 0.015 27.3% 36.4%
Division H
Finance ,
Insurance, and
Real Estate
20 16.3% 7.6% 0.023 0.012 0.000 0.022 0.010 45.0% 45.0%
Division I Services 251 35.0% 19.2% 0.023 0.013 0.001 0.034 0.003 23.9% 33.1%
Division J
Public
Administration
58 22.9% 11.6% 0.019 0.013 0.000 0.018 0.005 22.4% 41.4%

Linear Relative Rate Model
 Linear relative rate model (LRRM),
Poisson regression, gave best fit of data
 „LRRM lung cancer rate ratio ~1.6 for
mean cumulative SiO2 exposure, and rate
ratio of 5.4 and 6.0 at maximum SiO2
 „At 0.05 mg/m3 (NIOSH REL), estimate
lifetime excess lung cancer risk is ~2/100
for white and black males -- 20 times
greater than 1/1000 for lung cancer

0
5
10
15
20
25
30
35
0.001 0.005 0.010 0.020 0.030 0.040 0.050 0.060 0.070 0.080 0.090 0.100
TotalPopulationExcessMortalityRisk
Respirable Silica Concentration (mg/m3)
U.S. Lung Cancer Mortalities (1992)
40-Year Continous Exposure
Construction/Manufacture
Mean 0.024
Mining
Mean 0.012
Wholesale Trade
Mean 0.025
Mean 0.019
Trans/Com Elec/Gas
Mean 0.033
Agriculture and Forestry
Mean 0.029
Finance/Insurance and Services
Mean 0.023
Source:“Crystalline silica exposure and lung cancer mortality in diatomaceous earth industry workers: a quantitative risk
assessment”; F L Rice, R Park, L Stayner, R Smith, S Gilbert, and H Checkoway; Occup. And Environ. Medicine 2001;58:38–45.

2
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1
0 5 10 15 20 25 30
CumulativeExposure(mg/m
3
-years)
Linear RR Cumul Exp Log RR Cumul Exp 2-Piece Spline Linear RR Log Cumul Exp Categorical
RelativeRisk
Plot and Parameters of Relative Risk Models Fit to the Pooled Cohort
Data Originally Analyzed by Steenland et al. (2001)

Cumulative exposure to
crystalline silica
(mg/m3-y)
Person years
(×100000)
Silicosis mortality
rate (per 100000
py)*
Adjusted† silicosis
mortality rate (per
100000 py)
RR (95% CI)
n.a., not applicable.
0–0.99 3.637 4.7 4.7 1.00 (referent)
0.99–1.97 0.631 26.9 15.9 3.39 (1.42 to 8.08)
1.97–2.87 0.291 58.4 29.2 6.22 (2.56 to 15.12)
2.87–4.33 0.252 67.4 44.2 9.40 (3.71 to 23.80)
4.33–7.12 0.278 61.1 64.3 13.69 (5.04 to 37.18)
7.12–9.58 0.188 90.6 106.4 22.64 (7.88 to 65.10)
9.58–13.21 0.204 83.2 112.6 23.97 (8.05 to 71.32)
13.21–15.89 0.118 144.7 189.2 40.25 (13.25 to 122.3)
15.89–28.10 0.231 73.6 118.0 25.11 (8.09 to 77.91)
>28.10 0.073 233.6 299.1 63.63 (19.87 to 203.8)
Total
5.903
28.8 n.a. n.a. n.a.
Exposure Specific Mortality Rates and
Mortality Rate Ratios from Silicosis
*Each category includes 17 silicosis deaths (e.g., total 170).
†Adjusted for age in four categories, calendar period in eight categories, study in six categories, using Poisson regression.
n.a., not applicable.
Source: A 't Mannetje, K Steenland, M Attfield, P Boffetta, H Checkoway, N DeKlerk, and R-S Koskela, Exposure-response
analysis and risk assessment for silica and silicosis mortality in a pooled analysis of six cohorts; Occup Environ Med
2002;59:723-728.

Division
Specific
Industry
Sample
Mean
Cumulative
1-Month
Exposure
RR
Cumulative 3-
Month
Exposure
RR
Cumulative 6-
Month
Exposure
RR
Cumulative
1-Year
Exposure
RR
Division
A
Agriculture,
Forestry
0.029469 0.53 1.00 1.77 3.39 3.45 9.40 7.37 22.64
Division
B
Mining 0.011628 0.21 1.00 0.70 1.00 1.36 3.39 2.91 9.4
Division
C
Construction 0.023826 0.43 1.00 1.43 3.39 2.79 6.22 5.96 13.69
Division
D
Manufacturing 0.023645 0.43 1.00 1.42 3.39 2.77 6.22 5.91 13.69
Division
E
Trans/Com
Elec/Gas
0.032847 0.59 1.00 1.97 3.39 3.84 9.40 8.21 22.64
Division
F
Wholesale Trade 0.025387 0.46 1.00 1.52 3.39 2.97 9.40 6.35 13.69
Division
G
Retail Trade 0.02539 0.46 1.00 1.52 3.39 2.97 9.40 6.35 13.69
Division
H
Finance/Insurance 0.022692 0.41 1.00 1.36 3.39 2.65 6.22 5.67 13.69
Division
I
Services 0.02294 0.41 1.00 1.38 3.39 2.68 6.22 5.74 13.69
Division
J
Public
Administration
0.019039 0.34 1.00 1.14 3.39 2.23 6.22 4.76 13.69
Relative Risk of Silicosis Mortality from
Continuous Occupational Exposure

Number of Silicosis Deaths and Age-Adjusted Mortality Rate,
U.S. Residents Age 15 Years and Older, 1968-2005
Source: NIOSH, 2008c

Mortality Odds Ratios by Silica Exposure Category andCause of Death
from a U.S. Death Certificate Study*
Cause of Death
Exposure Category
p for
Trend
**Ever v
Low/no
Med v
low/no
High v
low/no
Super
High v
low/no
Silicosis 4.98 2.91 6.84 30.5 <0.001
Pulmonary Tuberculosis 1.47 1.34 1.60 2.48 <0.001
COPD 1.12 1.02 1.29 1.47 <0.001
Lung Cancer 0.99 0.88 1.13 1.13 <0.001
*Adapted from Calvert et al. (2003)
**Medium, high and super high pooled and compared to low/no group
***Super high exposure
Years
Total number of
Silicosis Deaths
Percent Change
(Reduction)
1970-1974 4,263
1975-1979 2,711 36%
1980-1984 1,958 28%
1985-1989 1,601 22%
1990-1994 1,389 13%
1995-1999 1,018 27%
2000-2004 809 20%
*NORMS database (http://webappa.cdc.gov/ords/norms.html)

 Consider ACGIH TLV as OSHA Action Level
(AL) and NIOSH REL as the new OSHA PEL
for all industries
 Include initial and periodic air monitoring
based on gap in work practices, change in
personnel/equipment, or signs of exposure
 Include medical surveillance provision –
initial/annual physicals for exposure of 30+
days or more often for signs of tuberculosis
Conclusions

 Require use of engineering/administrative
controls for exposure above the NIOSH REL
 Collaborate on technological innovation on
equipment/machinery and administrative
strategies to reduce exposure
 Conduct town hall meetings at local union
halls, town halls, and at small business
gatherings for building contractors/trades
Conclusions

 Use of respirators, protective clothing and
equipment for exposures above NIOSH REL
 Promote awareness of crystalline silica
dust hazards across all industrial sectors,
organizations, groups, and social media
 Provide personnel training/education on
OSHA requirements, dangerous work tasks,
signs/symptoms of exposure above the AL
Conclusions

 Collaborate with stakeholders including
physicians, healthcare providers, etc. to
educate workers on the health hazards
 Require physicians to report cases of
silicosis, COPD, lung cancer, and other
disorders linked to crystalline silica dust
 Require workers’ compensation carriers to
identify insureds with silica risks and solicit
help from OSHA Consultative Program
Conclusions

Longitudinal Study of Silica Dust

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