R E S E
R C H
N G L E
N S T I T U T E
REVIEW OF
NATIONAL EMISSION STANDARD FOR ASBESTOS
DRAFT
RTI Project No. 44U-1736-13
EPA Project No. 80/41
Prepared for
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emission Standards and Engineering Division
Contract No. 68-02-2056
RESEARCH TRIANGLE PARK, NORTH CAROLINA 27709
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Research Triangle Institute
P.O. Box 12194
Research Triangle Park, North Carolina 27709
REVIEW OF
NATIONAL EMISSION STANDARD FOR ASBESTOS
DRAFT
RTI Project No. 44U-1736-13
EPA Project No. 80/41
Prepared for
U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Emission Standards and Engineering Division
Contract No. 68-02-3056
John Copeland
Lead Engineer
Prepared by
Michael N. Laney
Laura A. Conrad
October 21, 1981
Dean F. Tolman, Manager
Applied Ecology Department
Operations Analysis Division
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TABLE OF CONTENTS
Chapter
1 SUMMARY ,
1.1 Introduction ,
1.2 Industry Description ,
1.3 Control Methods
1.4 Sampling and Analysis
1.5 Environmental and Health Impacts . . .
1.6 Enforcement and Compliance Experience.
1.7 Other Federal Regulatory Activities. .
INTRODUCTION
2.1 Background
2.1.1 Clean Air Act
2.1.2 The 1973 Asbestos Emission Standard
(40 CFR 61.22)
2.1.3 The 1974 Revisions. . . . ,
2.1.4 The 1975 Revisions. . . . ,
2.1.5 The 1977 Revisions. . . . ,
2.1.6 The 1973 Revisions. . . . ,
2.1.8 Executive Order 12044 . . ,
2.1.9 Adamo Wrecking Company vs.
2.1.10 Executive Order 12291 . . ,
Aooroach ,
2.3
INDUSTRY DESCRIPTION: MINING, MILLING, MANUFACTURING,
AND FABRICATING 3-1
3.1 Mining 3-1
3.1.1 Industry' Statistics 3-1
3.1.2 Process Description 3-1
3.1.3 Emission Sources 3-3
3.1.4 Control Techniques 3-3
3.1.5 Waste Disposal 3-4
3.1.6 Costs 3-4
3.2 Milling 3-4
3.2.1 Industry Statistics 3-4
3.2.2 Process Description 3-5
3.2.3 Emission Sources 3-7
3.2.4 Control Techniques 3-7
3.2.5 Waste Disposal 3-10
3.2.6 Costs 3-11
3.3 Asbestos Paper Products 3-11
3.3.1 Industry Statistics 3-11
3.3.2 Process Description 3-11
3.3.3 Emission Sources 3-17
3.3.4 Control Techniques 3-19
3.3.5 Waste Disposal 3-19
3.3.6 Costs 3-19
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TABLE OF CONTENTS (Continued)
.Chapter _P_age
3.4 Asbestos Friction Materials. ..... . . • 3-19
3.4.1 Industry Statistics 3'19
3.4.2 Process Description .......... 3-20
3.4.3 Emission Sources. 3-25
3.4.4 Control Techniques 3-28
3.4.5 Waste Disposal 3~28
3.4.6 Costs 3-28
3.5 Asbestos-Cement Products . . 3'29
3.5.1 Industry Statistics ^ 3~29
3.5.2 Process Description 3-33
3.5.3 Emission Sources 3-35
3.5.4 Control Techniques 3-39
3.5.5 Waste Disposal 3-41
3.6 Vinyl-Asbestos Floor Tile 3-42
3.6.1 Industry Statistics 3-42
3.6.2 Process Description 3-44
3.6.3 Emission Sources . . ...... 3-45
3.6.4 Control Techniques 3-45
3.6.5 Waste Disposal 3-45
3.6.6 Costs 3-45
3.7 Asbestos-Reinforced Plastics .... 3-45
3.7.1 Industry Statistics 3-45
3.7.2 Process Description 3-47
3.7.3 Emission Sources 3-49
3.7.4 Control Techniques 3-49
3.7.5 Waste Disposal 3-51
3.7.6 Costs . 3-51
3.8 Asbestos Paints, Coatings, and Sealants 3-51
3.8.1 Industry Statistics 3-51
3.8.2 Process Description 3-53
3.8.3 Emission Sources 3-56
3.8.4 Control Techniques 3-56
3.8.5 Waste Disposal 3-57
3.8.6 Costs 3-57
3.9 Asbestos Gaskets and Packings 3-57
3.9.1 Industry Statistics 3-57
3.9.2 Process Description 3-61
3.9.3 Emission Sources 3-63
3.9.4 Control Techniques 3-63
3.9.5 Waste Disposal 3-63
3.9.6 Costs 3-63
3.10 Asbestos Textiles 3-63
3.10.1 Industry Statistics 3-63
3.10.2 Process Description 3-64
3.10.3 Emission Sources 3-67
3.10.4 Control Techniques 3-67
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TABLE OF CONTENTS (Continued)
Chapter Page
3.10.5 Waste Disposal 3-69
3.10.6 Costs 3-69
3.11 Chlorine Manufacturing 3-69
3.11.1 Industry Statistics 3-69
3.11.2 Process Description 3-70
3.11.3 Emission Sources 3-72
3.11.4 Control Techniques 3-72
3.11.5 Waste Disposal 3-72
3.12 Asbestos Insulation 3-73
3.13 Shotgun Shells 3-73
3.13.1 Industry Statistics 3-73
3.13.2 Process Description 3-74
3.13.3 Emission Sources 3-74
3.13.4 Control Techniques 3-74
3.13.5 Waste Disposal 3-74
3.13.6 Costs 3-74
3.14 Asphalt Concrete 3-74
3.14.1 Industry Statistics 3-74
3.14.2 Process Description 3-75
3.14.3 Emission Sources 3-75
3.14.4 Control Techniques 3-75
3.14.5 Waste Disposal 3-75
3.14.6 Costs 3-75
3.15 Fabricating 3-76
3.15.1 Industry Statistics 3-76
3.15.1.1 A/C Products 3-76
3.15.1.2 Asbestos Friction Materials 3-77
3.15.1.3 V/A Floor Tile 3-78
3.15.1.4 Asbestos-Reinforced Plastics 3-78
3.15.1.5 Asbestos Paper Products 3-78
3.15.1.6 Asbestos Paints, Coatings,
and Sealants 3-79
3.15.1.7 Asbestos Gaskets, Seals, and Packing
Materials 3-79
3.15.1.8 Asbestos Textiles 3-79
3.15.2 Process Description 3-80
3.15.3 Emission Sources 3-80
3.15.4 Control Techniques 3-80
3.15.5 Waste Disposal 3-81
3.15.6 Costs 3-81
3.16 References 3-81
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TABLE OF CONTENTS (Continued)
Chapter
4 INDUSTRY DESCRIPTION: DEMOLITION, RENOVATION, AND
CONSTRUCTION 4-1
4.1 Industry Description: Construction 4-1
4.1.1 Industry Statistics 4-1
4.1.2 Renovation 4-5
4.1.3 Demolition 4-11
4.2 Process Descriptions ....... 4-16
4.2.1 Introduction 4-16
4.2.2 Construction 4-20
4.2.3 Renovation 4-27
4.2.4 Demolition 4-28
4.3 Emission Sources and Emissions 4-28
4.4 Control Techniques 4-29
4.4.1 A/C Pipe Installation 4-29
4.4.2 A/C Sheet Installation 4-32
4.4.3 Drywall Removal 4-33
4.4.4 Installation and Removal of Roofing Felts .... • 4-33
4.4.5 Removal of Nonfriable Insulation 4-34
4.4.6 Ecapsulation with Sealants 4-34
4.4.7 Renovation and Demolition 4-34
4.5 Waste Disposal 4-34
4.6 Costs 4-35
4.7 Status of Occupational Health Standards. . . 4-35
4.8 References ...... 4-36
5 CONTROL METHODS ...... 5-1
5.1 Fabric Filters 5-1
5.2 Wet Collectors 5-11
5.3 Electrostatic Precipitators 5-12
5.4 Demolition, Renovation, and Construction 5_13
5.4.1 Demolition and Renovation 5,13
5.4.2 Construction 5_lg
5.5 Substitutes 5_17
5.6 References 5_19
6 SAMPLING AND ANALYSIS ...... 6-1
6.1 Sampling Criteria g_l
6.2 Current Sampling Methods g_4
6.3 Analytical Methods ' \ g_5
6.3.1 Optical Methods [ ' 6_6
6.3.2 Electron Microscopy g_g
6.3.3 Physical and Chemical Analysis ] g_g
6.4 Other Sampling and Analysis Methods. g_^Q
6.5 Bulk Sample Analysis '.'.'. 6-11
6.5.1 Petrographic Microscopy '.'.'. 6-11
6.5.2 X-Ray Diffraction '.'.'. 6-12
6.5.3 Electron Microscopy * ] 6-12
6.6 Availability of Emission Data . . 6-12
6.7 References 6-13
vi
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TABLE OF CONTENTS (Continued)
Chapter Page
7 HUMAN HEALTH EFFECTS ASSOCIATED WITH INHALATION OF ASBESTOS . 7-1
7.1 Introduction 7-1
7.2 Health Hazards of Chrysotile Exposure 7-1
7.2.1 Asbestos Mortality 7-1
7.2.2 Lung Cancer Mortality 7-1
7.2.3 Pleura! and Peritoreal Mesothelioma 7-3
7.3 Nonoccupational Exposure to Asbestos 7-3
7.4 Factors that Modify Risk of Asbestos-Induced Disease . . 7-4
7.4.1 Smoking Habits 7-4
7.4.2 Age 7-4
7.5 Fiber Characteristics 7-5
7.5.1 Fiber Size 7-5
7.5.2 Fiber Type 7-6
7.6 Summary of Health Effects 7-6
7.7 References . . 7-7
8 ENFORCEMENT AND COMPLIANCE EXPERIENCE 8-1
8.1 Jurisdiction: State vs. Federal 8-1
8.2 Industry Concerns 8-1
8.3 Regional EPA Concerns 8-5
8.3.1 Work Practice Enforcement 8-5
8.3.2 Regulatory Language . . . 8-5
8.3.3 Notification 8-5
8.3.4 Emission Limitation 8-6
8.3.5 Unregulated Source 8-6
8.4 Applicability Determinations 8-6
8.5 Unregulated Emission Sources 8-6
8.5.1 Onsite Fabrication 8-6
8.5.2 Demolition 8-6
8.5.3 Contaminant Sources 8-9
8.5.4 Asbestos Mining 8-9
8.5.5 Fabricators 8-9
8.5.6 Encapsulants 8-10
8.5.7 Drilling Muds 8-10
8.6 References 8-11
9 OTHER FEDERAL REGULATORY ACTIVITIES 9-1
9.1 Environmental Protection Agency 9-1
9.1.1 Clean Air Act 9-1
9.1.2 Resource Conservation and Recovery Act 9-2
9.1.3 Toxic Substances Control Act 9-2
9.1.4 Clean Water Act 9-3
9.2 Occupational Safety and Health Administration 9-4
9.3 Consumer Product Safety Commission 9-4
9.4 Food and Drug Administration 9-4
9.5 Department of Transportation 9-5
9.6 Mine Safety and Health Administration 9-5
9.7 Other Federal Agencies 9-5
VII
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LIST OF TABLES
jjumber
2- 1 Provisions of the Current Standard 2-6
3- 1 United States Asbestos Production 3-2
3- 2 Estimated Total Annual Emissions from Asbestos Mining
in the United States 3-2
3- 3 Baghouse Emissions and Collection Efficiencies for
Asbestos Milling 3-8
3- 4 Ambient Air Concentrations of Fibers in the Vicinity of
Asbestos Mill Tailings Pile, Coalinga, California 3-8
3- 5 Summary of Ambient Asbestos Monitoring Data in Vicinities
of Asbestos Mill, Hyde Park, Vermont 3-9
3- 6 Estimated Total Annual Emissions From Asbestos Milling
in the United States 3-9
3- 7 Asbestos Consumption and Production of Asbestos Paper .... 3-12
3- 8 United States Asbestos Paper Products Industry Production,
1975 and 1979 3-13
3- 9 Producers of Asbestos Paper Products 3-14
3-10 Composition of Asbestos Paper Products •. 3-16
3-11 Estimates of Annual Asbestos Emissions from Asbestos Paper
Manufacturing in the United States, 1969 3-18
3-12 Estimates of Total Annual Environmental Releases of Asbestos
from Paper Manufacture in the United States, 1976 3-18
3-13 Domestic Producers of Asbestos Friction Materials 3-21
3-14 Estimates of Total Annual Asbestos Emissions from Friction
Material Processing in the United States 3-26
3-15 Estimates of Total Annual Asbestos Emissions from Friction
Product Manufacturing in the United States 3-26
3-16 Estimates of Total Annual Environmental Release of Asbestos
from Friction Material Manufacture in the United States . . 3-27
3-17 Producers of A/C Pipe 3-30
3-18 Manufacturers of A/C Sheet Products 3-31
3-19 U.S. Consumption of Asbestos in A/C Industry Compared
to Total U.S. Consumption, 1969-1980 3-32
3-20 Baghouse Emissions and Fiber Removal Efficiencies from
A/C Pipe Plants 3-37
3-21 Size Distribution and Fractional Removal Efficiencies
from Two A/C Pipe Plants 3-38
3-22 Estimates of Total Annual Emissions from Processing Asbestos
for A/C Pipe and Sheet Products in the United States. . . . 3-38
3-23 Estimated Total Annual Environmental Release of Asbestos
from A/C Pipe Manufacture in the United States 3-40
3-24 Estimated Total Annual Environmental Release of Asbestos
from A/C Sheet Manufacture in the United States 3-40
3-25 Producers of V/A Floor Tile 3-43
3-26 Estimates of Total Annual Emissions from V/A Floor
Tile Manufacture in the United States, 1969 3-46
3-27 Manufacturers of Asbestos-Reinforced Phenolic
Molding Compounds 3-48
3-28 Asbestos Consumed in Production of Asbestos-Reinforced
Plastics (Metric Tons) 3-48
v i i i
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LIST OF TABLES (Continued)
Number Page
3-29 Estimates of Total Annual Asbestos Emissions from the
Manufacture of Asbestos-Reinforced Plastics in the
United States 3-50
3-30 Manufacturers of Asbestos Coatings and Sealants 3-52
3-31 Asbestos Paint, Coating, and Sealant Consumption of Asbestos
(Short Tons) 3'52
3-32 1978 Net Sales for Producers of Asbestos Coatings and
Sealants 3-54
3-33 Primary Manufacturers of Asbestos Gaskets
and Packings 3-58
3-34 Asbestos Consumed in the Production of Gaskets
and Packings 3-62
3-35 Estimates of Total Annual Asbestos Emissions from the
Manufacture of Asbestos Gaskets and Packing
in the United States 3-62
3-36 Manufacturers of Asbestos Textiles 3-65
3-37 Asbestos Consumed in Textile Production in the
United States, 1978 to 1980 (Metric Ton) 3-65
3-38 Total Fiber Counts and Fiber Removal Efficiencies
for an Asbestos Textile Manufacturer 3-68
3-39 Chlorine Producers with Diaphragm Cells 3-71
4-1 Summary Statistics for Establishments With and Without
Payroll: 1977 and 1972 4-3
4-2 General Statistics For Establishments With Payroll By
Industry: 1977 4-6
4-3 Maintenance and Repair Receipt Data for Buildings Other than
Single-Family Dwellings 4-9
4-4 Maintenance and Repair Receipt Data for Nonbuilding
Construction . 4-10
4-5 Summary of Demolition-Data 4-17
4-6 Asbestos Products Consumed by the Construction Industry . . . 4-19
4-7 Distribution of Activities Among Different Construction
Types 4-21
4-8 Emission Sources and Occupational Exposures 4-30
5-1 Dust Control Devices 5-3
5-2 Bag Fabric 5-4
5-3 Bag Cleaning Mechanism 5-5
5-4 Air-to-Cloth Ratio 5-5
5-5 Pressure Drop Across Bag 5-6
5-6 Processes and Number of Sites Visited 5-7
5-7 Control Device Use 5-7
5-8 Baghouse-Cleaning Mechanisms 5-8
5-9 Comparison of Methods in Removal of an 8- x 12-foot Ceiling
Section 5-14
5-10 Inhibition of Asbestos Movement by Polyethylene Barriers. . . 5-14
IX
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LIST OF TABLES (Continued)
_N umber Pagi
6-1 Criteria for a Source Sampling Method for Asbestos for the
Acquisition of a Representative Sampling 6-2
6-2 Criteria for a Source Sampling Method for Asbestos to be
Compatible with the Analytical Method for Asbestos
Determination 6-3
8-1 States with NESHAP Authority 8-2
8-2 Asbestos NESHAP Determinations 8-7
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LIST OF FIGURES
Number Page
4-1 Types of Demolition Work 4-12
4-2 Permanent Employee Distribution . ........ 4-13
4-3 Average Temporary Employee Distribution 4-14
4-4 Comparison Between the Number of Permanent Employees and
the Average Number of Temporary Employees 4-15
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1. SUMMARY
1.1 INTRODUCTION
This Phase I review assesses the current national emission standard for
asbestos as part of the U.S. Environmental Protection Agency (EPA) project
number 80/41, "Review of Asbestos National Emission Standard," under EPA
contract number 68-02-3056, "New Source Performance Standards (NSPS) and
National Emission Standards for Hazardous Air Pollutants (NESHAPs)."
The impetus for this review was Presidential Executive Order 12044,
issued in March 1978, directing Federal agencies to improve existing and
future regulations. Existing regulations were to be reviewed periodically to
determine whether they were achieving policy goals of the Order. As a result,
review of the asbestos NESHAP was initiated. The Phase I review was continued
under authority of Executive Order 12291, which superseded Executive Order
12044 in February 1981.
This chapter summarizes information contained in this report.
1.2 INDUSTRY DESCRIPTION
Potential asbestos emission sources include companies that mine and mill
asbestos; manufacture intermediate or end products from, or use in their
operations, raw asbestos fibers; further process manufactured intermediate
products to produce a finished product; install asbestos-containing end
products; and remove asbestos-containing materials during renovation or
demolition of any building or structure. In 1980, U.S. asbestos production
totaled about 80,000 metric tons, 14 percent below the 1979 level, and imports
were about 327,000 metric tons, 36 percent below the 1979 level. Asbestos
consumption was nearly 359,000 metric tons, 36 percent below the 1979 level.
The construction industry accounts for two-thirds of U.S. asbestos
consumption, and U.S. demand appears to be leveling off or decreasing
slightly. Increasing regulations over health concerns associated with
asbestos, competition from substitutes, and an economic recession are largely
responsible for lessening asbestos demand.
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The following list of asbestos consumption, by product category,
indicates the relative sizes (in metric tons) of the various industry segments
in 1980.
Asbestos/cement (A/C) pipe 144,000
Flooring products ' ' v ^ 90^200
Friction products 43,700
Roofing products 26,500
Packing and gaskets 12,300
Coatings and compounds 10,900
Insulation 8,900
A/C sheet 7,900
Textiles 1,900
Plastics 1 300
Paper 500
Other 10,600
Total 358,700
The breakdown of asbestos consumption by product category will vary
depending on the definition of product category; e.g., the above list defines
the paper category to exclude flooring felt and roofing felt.
Major emission sources in mining include drilling, blasting, ore loading,
ore hauling, and ore dumping at the mill. Emission sources at mills include
primary processing (crushing and screening), drying, conveying, screening,
grading, fiberizing, fiber bagging, and tailings disposal. In manufacturing,
major emission sources generally include bag opening and dumping, mixing, and
finishing operations (drilling, cutting, and grinding). Fabricating resembles
finishing operations in manufacturing, so emissions are generally from
drilling, cutting, and grinding. Emissions from construction are not
considered significant since only a small amount of fabrication is onsite.
Emissions during demolition and renovation occur when asbestos-containing
building material or insulation is disturbed as in removing it from surfaces.
Very few emission test data exist for the asbestos industry.
1.3 CONTROL METHODS
The asbestos industry commonly uses local exhaust ventilation (LEV) with
hoods and enclosures to remove asbestos dust from the worker's environment.
Captured dust is exhausted to baghouses where it is collected. Pulse-jet and
mechanically shaken baghouses are used most frequently.
Electrostatic augmentation of fabric filtration is the only significant
control technology development that might be applicable to asbestos emissions.
Apparently, the rate of pressure drop decreases and collection efficiency
increases. This method has not yet been applied on a full-scale basis
1-2
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although pilot baghouse studies controlling fly ash are promising. Other
efforts directed toward optimizing baghouse performance through variations in
cleaning frequency, duration, and intensity have been only partially
successful.
For installation of asbestos-containing products and demolition and
renovation of asbestos-containing structures, a variety of techniques are used
to control emissions. Special cutting tools are used in field fabrication of
asbestos products; LEV systems for portable tools are not used extensively.
Asbestos emissions resulting from renovation and removal of friable materials
containing asbestos are controlled by use of amended water before scraping,
picking, and drilling and by containing emissions within areas where removal
is undertaken.
Little work is being done to improve emission control methods for use in
demolition and renovation. The United States Navy presently is developing an
asbestos-removal method for use in ship repair, still in experimental stages.
Restrictions on the quantity of asbestos used in products and complete
elimination of some asbestos-containing products by industry probably have
also reduced asbestos emissions. These methods are largely a response to
regulatory activities to reduce the potential for human exposure to asbestos.
1.4 SAMPLING AND ANALYSIS
Techniques are developed for analyzing bulk samples for asbestos content.
However, there is presently no reference method for measuring asbestos stack
emissions. While progress has been made in refining the provisional electron
microscopy method, interlaboratory and intralaboratory variations, high costs,
and lengthy analysis continue to prevent its acceptance as a reference
analysis method. A feasibility study recently has been performed regarding
development of a measurement method compatible with the provisional analytical
method, and actual development is at least 2 years away.
1.5 ENVIRONMENTAL AND HEALTH IMPACTS
Inhalation of asbestos fibers has been associated with asbestosis,
respiratory cancer, and mesothelioma. The original decision to control
asbestos emissions into the atmosphere was based largely on a National Academy
of Science report. Since then, researchers have been unable to determine if
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there is a safe exposure level below which asbestos-induced cancer will not
occur. Consequently, EPA still believes human exposure to airborne asbestos
should be reduced to the greatest extent practicable.
1.6 ENFORCEMENT AND COMPLIANCE EXPERIENCE
Major hindrances to enforcing the asbestos NESHAP include the apparent
difficulty with enforcing nonemission provisions, difficulty in interpreting
the standard, and inadequate reporting by demolition contractors. Generally,
the asbestos industry believes the standard to be workable and effective in
reducing asbestos exposures.
1.7 OTHER FEDERAL REGULATORY ACTIVITIES
At least six Federal agencies, excluding EPA, currently have or are
proposing regulations aimed specifically at regulating asbestos. Within EPA,
several regulations exist or are proposed that are directed specifically at
asbestos or that are generic in nature but result in regulation of asbestos.
These standards should be assessed during Phase II to determine the extent to
which they interface with revision of the asbestos NESHAP.
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2. INTRODUCTION
This Phase I study reviews and recommends alternatives for revising
the national emission standard for asbestos. It is submitted to the U.S.
Environmental Protection Agency (EPA) as part of EPA Project Number 80/41,
EPA Contract Number 68-02-3056, "New Source Performance Standards and
National Emission Standards for Hazardous Air Pollutants."
This chapter discusses the background for review of the asbestos
national emission standard and summarizes the study objectives and
approach. Chapters 3 and 4 of this report describe the manufacturing
industry and the demolition and renovation industry, respectively. Chapter
5 discusses control systems, Chapter 6 discusses sampling and analysis, and
Chapter 7 summarizes environmental impacts. Chapter 8 examines enforcement
activities, and Chapter 9 reviews other applicable Federal regulations.
2.1 BACKGROUND
Legal and Congressional actions that resulted in development of the
asbestos emission standard, subsequent actions that amended the standard,
and events responsible for this review are presented here. The Clean Air
Act, the 1973 national emission standard for asbestos and subsequent
amendments, Executive Orders 12044 and 12291, and the U.S. Court decision
in the Adamo Wrecking Company vs. the United States are summarized in the
following passages.
2.1.1 Clean Air Act
In 1963, by enacting the Clean Air Act, the U.S. Congress established
a national program to control air pollution in response to growing public
concern. This program established funds for air pollution control
research. The Act was amended by the Air Quality Act of 1967, which
expanded research functions, authorized assistance to both State and
municipal programs, provided a means to force polluters to control air
2-1
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pollution, and authorized the Federal Government to file suit against
industries responsible for air pollution emergencies.
In 1970, Congress further amended the Clean Air Act with the Clean Air
Act Amendments. Through these amendments, Congress created EPA and
directed it to promulgate and set standards to control air pollution.
Congress gave EPA the authority, under Sections 110, 111, and 112 of the
amended Act, to create National Ambient Air Quality Standards (NAAQS), New
Source Performance Standards (NSPS), and National Emission Standards for
Hazardous Air Pollutants (NESHAPs), respectively. Under this authority,
EPA designated asbestos a hazardous air pollutant.
Congress amended the 1970 Clean Air Act in August 1977, after 7 months
of hearings and numerous markup sessions during the years 1972 through
1976. Sections 110, 111, and 112 were all affected. Section 112 of the
Clean Air Act was amended to allow EPA to promulgate design, equipment, or
operational standards to control hazardous emission sources, where an
emission limit is not feasible.
2.1.2 The 1973 Asbestos Emission Standard (40 CFR 61.22)
On April 6, 1973 (38 FR 8826), EPA promulgated the national emission
standard for asbestos. It prohibited visible emissions from asbestos mills
and nine different manufacturing industries, specified certain work
practices for demolition of structures that contain friable asbestos,
limited to less than 1 percent asbestos content of spray-on materials used
for certain insulation applications, and prohibited most uses of asbestos
tailings for surfacing roadways.
2.1.3 The 1974 Revisions
Revisions to the standard were promulgated on May 3, 1974 (39 FR
15398), to clarify some portions of the regulation. Revisions included
definitions for asbestos mill, commercial asbestos, manufacturing, and
demolition. Language in the paragraphs under demolition was revised for
clarity. Paragraph (g) was added, which exempted sources from no visible
emissions requirements where the presence of uncombined water was the sole
reason for violation.
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2.1.4 The 1975 Revisions
On October 14, 1975 (40 FR 48292), EPA amended the asbestos standard.
The 1975 changes clarified the definition of demolition by including
removal or stripping of friable asbestos materials. Revisions defined the
following terms: friable asbestos material, control device asbestos waste,
renovation, planned renovation, emergency renovation, adequately wetted,
removing, stripping, fabricating, inactive waste disposal site, active
waste disposal site, roadways, and asbestos-containing waste material.
The provision regarding surfacing of roadways was revised to prohibit
use of asbestos-containing waste and asbestos tailings. EPA revised
coverage of the asbestos emission standard by extending no visible emission
requirements to two additional manufacturers: manufacturers of shotgun
shells and manufacturers of asphalt concrete. For clarification, EPA
specified that there shall be no visible emissions from manufacturing
operations ". . . if they use commercial asbestos. . ."
Provisions regarding demolition were expanded to include renovation.
In the 1975 revisions, demolition and renovation operations Included
stripping and removing requirements for certain items insulated or
fireproofed with asbestos materials in addition to pipes, boilers, and
load-support ing structural members itemized in the original standard.
Revisions suspended wetting requirements under freezing weather conditions
and granted use of local exhaust ventilation (LEV) and collection systems
in lieu of wetting when, as a result of wetting, equipment damage would be
unavoidable during renovation operations.
Revisions extended additional requirements to demolition of facilities
authorized by State or local governments besides notification requirements
already in effect. Requirements for stripping of friable asbestos material
from previously removed units and for wetting were made applicable to
State-authorized demolitions. The uncombined water condition in paragraph
(g) of the standard was also extended to State-authorized demolitions.
The 1975 revisions added requirements for fabrication using commercial
asbestos and extended the no visible emissions requirement to fabricators
of cement building products, friction products, and cement or silicate
board.
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EPA found it necessary to divide fabrication operations into two main
categories: field fabrication and central shop fabrication. From its
investigation, EPA concluded that asbestos products other than friable
insulating products are field fabricated to only a limited extent and that
fabrication of certain asbestos products in central shops is a major
emission source. Therefore, field fabrication was not included in the
revisions.
Reporting requirements were revised to exempt any owner or operator
who intends to spray materials containing less than 1 percent asbestos to
insulate or fireproof equipment and machinery.
The option of using specified air-cleaning methods in place of
complying with no visible emissions requirements was extended to demolition
and renovation, fabrication, and waste disposal.
The 1975 revisions prohibited insulating with either friable, molded
insulating materials or wet-applied insulating materials that are friable
after drying.
Waste disposal requirements for manufacturing, fabricating, demolition
and renovation, and spraying operations were added by the 1975 revisions.
Visible emissions were prohibited by the 1975 revisions during collection,
processing, packaging, transporting, or deposition of any asbestos-
containing waste material. Revisions specify two alternative waste
disposal methods, which could be used instead of the no visible emissions
requirement. The 1975 revisions also specified operating conditions for
asbestos waste disposal sites.
Waste disposal requirements for asbestos mills were given separately
from other waste disposal provisions in the 1975 revisions. However, they
are similar to the other waste disposal provisions except that they allow a
wetting agent to be mixed with asbestos-containing waste from mills.
Requirements for owners of inactive waste disposal sites, which were
operated by milling, manufacturing, and fabricating sources, were added
with the 1975 revisions. These requirements included no visible emissions
to the outside air and methods to prevent emissions from asbestos-
containing waste material and asbestos tailings piles.
2-4
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Air-cleaning requirements (40 CFR 161.23) were not changed by the 1975
revisions, but reporting requirements (40 CFR 61.24) were revised to
include waste disposal activities.
2.1.5 The 1977 Revisions
The 1977 revisions clarified that the standard's demolition and
renovation provisions apply when friable asbestos is removed from nonload-
supporting structural members.
2.1.6 The 1978 Revisions
In June 1978 (43 FR 26372), requirements for demolition and renovation
were extended to cover operations involving friable asbestos-containing
material; references to asbestos-containing insulation and fireproofing
were removed. Coverage of the asbestos-spraying provisions was also
extended to all materials (not just insulating and fireproofing materials)
that contain more than 1 percent asbestos. Also, EPA exempted from the
spraying provisions spray-on applications of materials in which asbestos
fibers are encapsulated with bituminous or resinous binders.
2.1.7 The Current Standard
Provisions of the current standard limit emissions from milling and
manufacturing, prohibit uses of asbestos-containing materials, provide for
work practices in demolition and renovation operations, and require certain
procedures for waste disposal and disposal site maintenance. The standard
is summarized in Table 2-1.
2.1.8 Executive Order 12044
On March 23, 1978, President Jimmy Carter issued Executive Order
12044, which directed the executive agencies to improve existing and future
regulations. Among the requirements of the Executive Order were those that
required Federal agencies to ". . . periodically review their existing
regulations to determine whether they are achieving the policy goals of
this Order."
In May 1979, EPA published its response to the Order in the Federal
Register (44 FR 30988). The response contained the criteria and process
EPA would use in selecting regulations for review. EPA responded that the
first reviews were to be those previously scheduled in response to
statutory or judicial authorities. However, NESHAPs were not under
2-5
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TABLE 2-1. PROVISIONS OF THE CURRENT STANDARD
Operation
Provisions
Mi 11 i ng
Surfacing roadways
No visible emissions
permitted
are
Manufacturing
Demolition and
renovation
Surfacing roadways with
asbestos tailings or
asbestos-containing waste
from manufacturing, demo-
lition, spraying, or fabrica-
ting is prohibited
No visible emissions are
permitted from the manu-
facture of the following
materials that use commercial
asbestos:
Or, air-cleaning methods
in Section 61.23 must be
used to collect emissions
before venting
Provision not required for
temporary roadways on
an area of asbestos ore
deposits
Or, air-cleaning methods
in Section 61.23 must be
used to collect emissions
before venting
1. Cloth, cord wicks, tubing,
tape, twine, rope, thread,
yarn, roving, lap, or
other textile materials;
2. Cement products
3. Fireproofing and insulating
materials
4. Friction products
5. Paper, millboard, and felt
6. Floor tile
7. Paints, coatings, caulks,
adhesives, and sealants
8. Plastics and rubber
materials
9. Chlorine
10. Shotgun shells
11. Asphalt concrete
Written notification with
specific information
regarding demolition or
renovation projects must be
given to EPA
Only the name and address
of the project owner or
operator is required
when the amount of
friable asbestos material
is less than 80 meters
(ca. 260 feet) on pipes
or 15 square meters (ca.
160 square feet) on other
structural members
2-6
(Continued)
-------
TABLE 2-1. PROVISIONS OF THE CURRENT STANDARD (Continued)
Operation
Provisions
Demolition and
renovation
(continued)
Renovation
be
Friable asbestos materials
must be removed before
wrecking
Friable asbestos materials
must be adequately wetted
during stripping
Friable asbestos materials
exposed during cutting or
disjointing of units or
sections of structural
members being removed must
adequately wetted
Friable asbestos materials
must be adequately wetted
during stripping of units or
sections of structural
members being removed
All friable asbestos materials
removed or stripped must be
adequately wetted for the
remainder of demolition or
renovation operation. Do not
throw to ground; if more than
50 feet above ground level
(except units or sections),
transport to ground via dust-
tight chutes or containers
If equipment damage results
from wetting friable asbestos
materials during stripping,
LEV and collection systems
that exhibit no visible
emissions must be used; prior
to use, approval must be
obtained from EPA
Provision not required for
structural members
encased in concrete
Provision not required
when temperatures drop
below 0° C, but structur-
al members coated with
friable asbestos must be
removed in sections or
units
Provision not required
when temperatures drop
below 0° C, but structur-
al members coated with
friable asbestos must be
removed in sections or
units, if possible
Or, LEV and collection
systems that exhibit no
visible emissions must be
used
Or, air-cleaning methods
in Section 61.23 must be
used
Or, air-cleaning methods
in Section 61.23 must be
used
2-7
(Continued)
-------
TABLE 2-1. PROVISIONS OF THE CURRENT STANDARD (Continued)
Operation
Provisions
Sprayi ng
Fabrication
Insulating
Waste disposal
No visible emissions are
permitted when materials con-
taining more than 1 percent
asbestos are sprayed on
equipment or machinery
Materials sprayed on other
structures or structural
members cannot contain 1
percent or more of asbestos
Written notification with
site-specific information
must be provided to EPA when
the intent is to spray
materials containing more
than 1 percent asbestos on
equipment or machinery
No visible emissions from
fabrication of the following
products are permitted if
performed in a central
location:
1. Cement bulding products
2. Friction products, except
those installed on motor
vehicles
3. Cement or silicate board
Application of molded and wet-
applied insulating materials
that contain asbestos and are
friable are not permitted
No visible emissions are
permitted from the collec-
tion, processing, packaging,
transporting, or deposition
of asbestos-containing waste
material generated from an
asbestos emission source
Or, air-cleaning methods
in Section 61.23 must be
used; provision not
required for materials in
which asbestos fibers are
encapsulated with binders
Notification not required
for spraying of materials
in which asbestos fibers
are encapsulated with
binders
Or, air-cleaning methods
in Section 61.23 must be
used
Or, asbestos-containing
waste must be treated
with water, sealed into
leak-tight containers,
and containers labelled
with a warning
2-8
(Continued)
-------
TABLE 2-1. PROVISIONS OF THE CURRENT STANDARD (Continued)
Operation
Provisions
Waste disposal
(continued)
No visible emissions are
permitted from wetting
asbestos mill waste that
contains asbestos
.Inactive disposal
sites
No visible emissions are
permitted from inactive
disposal sites containing
asbestos waste
Air-cleaning
methods
Fabric filter collection
devices must be used
Or, the waste must be
processed into a
nonfriable form
Or, for milling oper-
ations, asbestos-contain-
ing waste must be treated
with a wetting agent
prior to disposal
Or, air-cleaning methods
in Section 61.23 must be
used
Provision not required
when the temperature at
the disposal site is less
than -9.5° C (15° F)
Or, the waste must be
covered with 15
centimeters (ca. 6
inches) of compacted non-
asbestos-containing
material and vegetation
Or, the waste must be
covered with 60
centimeters (ca. 2 feet)
of compacted nonasbestos-
containing material
Or, for tailings disposal
sites, a resinous or
petroleum-based, dust-
suppressant must be
appl ied
Provision not required if
fabric filtration methods
create a fire or explo-
sion hazard
(Continued)
2-9
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TABLE 2-1. PROVISIONS OF THE CURRENT STANDARD (Continued)
Operation
Provisions
Ai r cleaning
methods
(continued)
Reporting
Waste disposal
sites
Or, another filtering
method equivalent to
fabric filtration methods
must be used
The pressure drop of the
collection device must be
maintained at or below 4
inches of water
Air permeability must not
exceed 30 cubic feet per
minute per square foot of
woven fabric or 35 cubic feet
per minute per square foot of
felted fabric
A unit contacting energy of at
least 40 inches water gage
pressure must be used if wet
collectors are permitted
The following information
regarding collection devices
shall be provided to EPA:
1. Description of the
emission control equip-
ment
2. Pressure drop
3. Air flow permeability of
woven fabric and type of
yarn used
4. Density, minimum thick-
ness, and air flow
permeability
No visible emissions are
permitted from active waste
disposal sites where
asbestos-containing waste has
been deposited
40 and 45 cubic feet per
minute per square foot of
woven and felted fabric,
respectively, is per-
mitted for ore driers
Or, the asbestos-contain-
ing waste material must
be covered with
15 centimeters (ca. 6 in-
ches) of nonasbestos-
containing material at
the end of each operating
day or at least once
every 24-hour period
2-10
(Continued)
-------
TABLE 2-1. PROVISIONS OF THE CURRENT STANDARD (Continued)
Operation
Provisions
Waste disposal
sites
(continued)
Signs shall be
entrances and
property line
posted at
along the
all
Or, the deposited
asbestos-containing waste
must be covered with a
resinous or petroleum-
based dust suppressant at
the end of each operating
day or at least once
every 24-hour period
Posting not required when
the asbestos-containing
waste is covered with 15
centimeters (ca. 6
inches) of nonasbestos-
containing material or a
natural barrier hinders
access
Warning signs must be 20 inches
by 14 inches and conform to
the format required by the
Occupational Safety and Health
Administration (OSHA) Standard,
29 CFR 1910.145(d)(4)
2-11
-------
statutory mandate to undergo review and were selected under the following
criteria developed in response to the Order:
Estimated high actual costs to the public of implementing and
maintaining the regulation,
Estimated low actual benefits,
Existence of overlap with other regulations (issued by EPA or
another agency),
Need for integration with other programs,
Existence of preferable alternatives,
Low degree of compliance,
Low enforceability,
High reporting burden,
Lack of clear language,
Length of time since the regulation became effective or was last
substantively amended,
Intensity of public sentiment in favor of changing the
regulation, and
Availability of adequate data for analyzing the regulation's
effectiveness and cost.
EPA responded that it would summarize its assessment of each
regulation and choose those for formal review. Reviews were to be
conducted within 5 years.
Once regulations were selected, review would follow procedures for
new standards development and would not duplicate any previously prepared
analysis still val id.
Based on the above procedures, review for the asbestos NESHAP was
initiated.
2.1.9 Adamo Wrecking Company vs. United States
The 1978 decision by the U.S. Supreme Court in Adamo Wrecking Company
vs. United States, held that the work practice provisions in the asbestos
standard were not emission standards and that the Clean Air Act Amendments
of 1970 did not empower EPA to issue nonemission (e.g., work practice)
standards. However, Congress acted in 1977 to broaden EPA's authority by
amending Section 112 of the Act. The 1977 Amendments allow EPA to
promulgate design, equipment, and operational standards to control
hazardous emission sources where a numerical emission limit is not
2-12
-------
feasible. The 1977 Amendments, although they allowed promulgation of
nonemission standards, did not specifically provide authority to enforce
these standards. The question of enforceability of nonemission standards,
in general, was resolved through passage in 1978 of the Health Services
Research, Health Statistics, and Health Care Technology Act. This act
equated design, equipment, work practice, and operational standards with
emission standards, thereby allowing EPA to enforce both emission and
nonemission standards. However, as a result of these actions, EPA needs to
repropose the work practice provisions promulgated prior to the 1977
Amendments.
2.1.10 Executive Order 12291
On February 17, 1981, President Reagan signed Executive Order 12291.
This order requires all agencies to prepare a regulatory impact analysis
(RIA) for all proposed regulations and to continue reviewing all proposed
and existing regulations.
2.2 OBJECTIVES
The objective of the Phase I review is to determine the need for
revising the current asbestos NESHAP. The determination will reflect
technological and regulatory development occurring since promulgation of
the NESHAP and other information pertinent to determining the standard's
adequacy. In addition, the review is tc identify gaps, if any, in the
asbestos NESHAP. If revision of the standard is recommended, suggestions
concerning the extent and form of revisions will be presented.
2.3 APPROACH
The result of Phase I will be a recommendation to revise or not to
revise the NESHAP and a discussion of findings and conclusions. The
following information is examined:
Use by affected industries of best available technology (BAT),
Availability of sampling and analytical methods for determining
emission concentrations,
Information linking health risks to exposure levels,
Experience with enforcing the asbestos NESHAP,
Other regulatory activities pertaining to asbestos, and
Deficiencies in the asbestos NESHAP.
2-13
-------
The approach used in gathering and evaluating this information
involved the following:
Examination of EPA's background documents on the current
standard and amendments,
Use of computerized literature search,
Visits to asbestos mining, milling, manufacturing, and demolition
sites,
Contacts with EPA and with EPA contractors,
Contacts with EPA regional offices,
Contacts with other Federal regulatory agencies,
Contacts with trade associations, and
Contacts with control equipment vendors.
2-14
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3.0 INDUSTRY DESCRIPTION: MINING, MILLING, MANUFACTURING,
AND FABRICATING
3.1 MINING
3.1.1 Industry Statistics
Currently, four asbestos mines are operating in this country.
California is the site for two mines: Calaveras Asbestos Corporation in
Copperopolis (Calaveras County), which led the nation in output in 1980, and
Union Carbide Corporation in Santa Rita (San Benito County). The Vermont
Asbestos Group's Lowell mine (Orleans County, Vermont) was second in
production in 1980, while Jaquays Mining Corporation in Gila County,
Arizona, is the State's only active mine.* Mines that have closed recently
include Atlas Asbestos Corporation in Santa Cruz, California, and Powhatan
Mining Company in Burnsville, North Carolina.1 The Alaska Asbestos Company,
jointly owned by International Paper Company, Mclntyre Mines, Limited, and
Tanana Asbestos Corporation, maintains an active program of drilling and
engineering feasibility at the Eagle property owned by Doyon, Limited.1 All
of the mines are far removed from large population centers.
In 1979, the United States produced 17 percent—93,000 metric tons—of
domestic consumption, which totaled 561,000 metric tons.2 Total production
in 1980 was 80,079 tons, down approximately 14 percent from 1979.1 Table 3-1
presents 1979 production information and fiber grades produced by each
mining operation.
3.1.2 Process Description
The asbestos content of ore bodies varies with location, from 2 to 3
percent asbestos by weight at the Vermont mine to 60 percent at Union
Carbide's mine in San Benito, California. Surface mining methods are used
where the asbestos-containing ore lies near the surface and is not bound
within massive rock deposits. Such ore can be bulldozed or removed by a
power shovel, a method used at the Union Carbide mine. An initial size
classification step is also carried out at the site. In Vermont and the
Copperopolis district of California, open pit mining is used, and blasting
is required to loosen the overburden for removal. Holes are drilled for
placement of explosives. Secondary blasting may follow primary blasting to
3-1
-------
TABLE 3-1. UNITED STATES ASBESTOS PRODUCTION3*4.5
Mining
company
Calaveras
Union Carbide
Vermont Asbestos
Group
Jaquay
TABLE 3-2.
Source
Mining and milling
Mining
Uncontrolled
50% controlled
80% controlled
Mining
Type of
asbestos
Chrysotile
Chrysotile
Chrysotile
Chrysotile
ESTIMATED TOTAL
MINING IN THE
Year
1968
1969
1969
1969
1974
Grades
4-7
7
3-7
Mostly Grade 3
ANNUAL EMISSIONS FROM
UNITED STATES6 »7>8
Annual emissions
(metric tons)
5,105
578
288
110
373
Annual
production, 1979
(metric tons)
32,000
32,000
30,000
550
ASBESTOS
Reference
6
7
7
7
8
3-2
-------
reduce large boulders to manageable size. The ore is loaded by mechanical
shovels into ore-hauling trucks and transported to a stockpile located at a
primary jaw crusher. In Arizona where asbestos deposits are often narrow
veins extending far below the surface, it is necessary to resort to
underground mining. The ore is freed by drilling and blasting, and the
fiber is mined in drifts and stopes using a modified room and pillar
method.6
3.1.3 Emission Sources
Potential emission sources during mining include drilling, blasting,
bulldozing, loading ore into hauling trucks, hauling ore and other traffic
within the mine, initial processing at the mine site, and dumping ore in
stockpiles at the mill. Emissions will be influenced by meteorological
conditions, with wet conditions helping reduce emissions in most mine
activities. Ores with high moisture content will be less likely to produce
emissions due to disturbances such as wind, loading, and dumping.
Estimates, not based on sampling data, of annual emissions from mines are
presented in Table 3-2. One esimate is based on observations made and
information obtained during field trips.6 The author of one report states
that the estimates are uncertain and may be off by at least an.order of
magnitude.8
3.1.4 Control Techniques
Control methods currently used in asbestos mining have changed little
in recent years and appear to represent best available technology (BAT).
Emissions from drilling are controlled through use of fabric filters
situated on the drilling rigs. Drilling is accomplished through a hood over
the drilled hole; rubber aprons form its sides. -Air is exhausted from the
hood to the fabric filter. The area under the hood acts as a settling
chamber, preventing large chips from being drawn into the fabric filter.9
The use of wet drilling methods to control emissions is excluded from some
asbestos mining; e.g., in Vermont, where cold weather would cause the water
to freeze.
Emissions from blasting are difficult to control. Control methods
presently used in this country include use of gel blasting agents and
injection of water containing a wetting agent into the drilled holes prior
3-3
-------
to blasting. The ore's moisture content helps control emissions during
blasting.
Removal of overburden, shoveling of ore into trucks for hauling,
preliminary screening at the mine, and surface scraping of ore are
uncontrolled emission sources, which the water content of fresh ore helps
reduce.
Emissions caused by trucking ore from the mine to the mill's storage
piles are reduced by wetting the roads in and around the mine. Large water
tankers are used for this purpose. Also, requiring trucks to travel slowly
in and around the mine helps reduce emissions both from the road surface and
the loaded ore. Large-capacity trucks reduce the trips necessary between
mine and mill. Ore stockpiled at the mill may be wetted from time to time
to control emissions.
The current emission standard does not regulate the mining of asbestos.
Previously regulated by the Bureau of Mines, asbestos mining is now
regulated by the Mine Safety and Health Administration (MSHA).
3.1.5 Waste Disposal
Overburden from mining is hauled and dumped to create a large pile. No
attempts are made to stabilize these piles in any way.
3.1.6 Costs
Mining costs and emission control costs were not collected during
Phase I.
3.2 MILLING
3.2.1 Industry Statistics
The four mining sites currently operating in the United States also
operate the only four active mills in this country. They are Calaveras
Asbestos Corporation and Union Carbide Corporation in California, Vermont
Asbestos Group in Vermont, and Jaquays Mining Corporation in Arizona. The
mills of Calaveras Asbestos Corporation and Vermont Asbestos Group are
located at the mine sites. Union Carbide's mill is near King City, about 90
kilometers (55 miles) from its Coalinga mine site. Jaquays Mining
Corporation's mill is in Globe, Arizona, approximately 48 kilometers (30
miles) from the Gil a County mine site. Table 3-1 summarizes production
3-4
-------
information for each mining and milling company and the asbestos grade
produced by each company. Total domestic production in 1980 was 80,079
tons.l
3.2.2 Process Description
Asbestos milling is a complex operation primarily involving separation
of fiber from rock, and classifying fiber by length; the basic method has
changed little over the past several years.2 The following description of
asbestos milling is excerpted from Control Techniques for Asbestos Air
Pollutants.10
Separation of asbestos fibers from rock typically is initiated by
conveying mine ore by a large hopper and pan feeder to a primary, jaw-type
crusher that accepts boulders up to 48 inches in diameter and reduces these
to fragments not larger than 6 inches in diameter. Subsequently, this
crushed rock is transported by belt conveyor to trommel screens, which are
rotating cylinders with various sized openings, or to a stationary-bar
grizzly, a type of screen, for the sizing operation. Ore fragments greater
than 1-1/4 inch in diameter are routed to a secondary cone-type crusher for
further reduction, and outputs of primary and secondary crushers are
conveyed to a wet-ore storage pile exterior to the mill. This stockpile
usually contains sufficient ore to sustain mill operation for an extended
time.
Wet ore is extracted from the bottom of the wet-ore stockpile by a
vibrating-chute feeder located in an underground tunnel. The wet ore enters
slowly rotating cylindrical dryers that permit baffles internal to the
dryers to pick up and release the wet ore continually, thereby exposing it
to a drying current of hot air.
The dried ore is conveyed by belt to a vibrating screen that sizes the
ore for fine crushing. The undersized screenings and the output of the
final crushers form a dry-rock stockpile, which is housed to protect it from
the exterior environment.
The finely crushed, dried asbestos ore next traverses a rock circuit,
where it undergoes several screenings, fiberizing, and aspiration to remove
freed fibers and further disintegrate rock. The principal purpose of
3-5
-------
this set of operations is to separate asbestos fibers from rock, but the
circuit secondarily functions to grade fibers according to length.
In the rock circuit, cleaned rock is finally expelled to an exterior
tailings dump. As the air streams that convey aspirated asbestos fibers
pass through cyclone collectors, the fibers are removed for cleaning and
additional grading. Exhausts from these collectors are ventilated to
gas-cleaning devices.
Fiber-cleaning circuits are intended to perform additional fiber
opening, to classify and separate opened fibers from rock and unopened
material, and to carry out further fiber-length grading. Grading,
screening, aspirating, and opening are involved in this circuit; in
addition, some material is rejected as waste. The aspirated asbestos fibers
are deposited into cyclone collectors and subsequently delivered to the
grading circuit as long, medium, short, and extra-short fibers. Cyclone
exhausts are directed to a gas-cleaning device.
Asbestos fibers are separated into numerous standard grades and
cleansed further in the grading circuit. Standard grading machines affect
additional opening of fibers and facilitate shorter fiber removal. Air
aspiration from vibrating screens separates additional fine dust, fine rock
fragments, and unopened fibers. Cyclone collectors are exhausted through
fabric filters to control asbestos-containing dusts. Asbestos fibers are
machine packaged either by compressing the material into a dense bundle or
by blowing the material into bags.
The Coalinga deposit of asbestos ore in California presents an
exception to the above practices in that no primary crushing is carried out
prior to ore drying. Furthermore, a wet process is employed for milling.
An ore-water mixture is carried through a proprietary grinding and
separating process to mill the asbestos almost entirely into fibrils. A
subsequent dewatering operation produces cylindrical pellets of asbestos
fibers, which measure approximately 3/8 inch in diameter and as much as 3/4
inch in length and are formed and subsequently dried without a binder. Some
of the asbestos is marketed in pellet form to end users. If a completely
opened form of asbestos is needed for a manufacturing process, the dry
pellets can be ground either at the mill or by the end user.
3-6
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3.2.3 Emission Sources
Most phases of asbestos milling are potential emission sources, which
may occur from the following:
Dumping mine ore onto wet-ore stockpiles or into receiving
hoppers;
Stockpile surfaces that have become dry and are subject to wind
erosion;
Belt conveying of asbestos ore, fibers, and asbestos-containing
tailings;
Conveyor system transfer points;
Feed and discharge ports of crushers;
Ore dryers;
Dry ore storage;
Grading screens;
Bagging of asbestos; and
Tailings piles.
Few emission data are available for asbestos milling operations. Table
3-3 presents results of emission tests performed on baghouses during the
early 1970s at the Vermont mill and at a Canadian mill. Samples were taken
upstream and downstream from the baghouse and collection efficiency
calculated. Both phase contrast and electron microscopy were used to count
fibers. Table 3-4 presents emission test results for sampling at the
tailings pile of an asbestos mill (currently not open) near Coalinga,
California. Samples were taken between rain showers and the only tailings
dumped were in a dry, dusty state.9 Results of ambient air samples taken in
the vicinity of an asbestos mill in Hyde Park, Vermont, are presented in
Table 3-5. Engineering estimates—and not precise quantities—of annual
emissions from asbestos milling in the United States are given in Table 3-6.
3.2.4 Control Techniques
Wet-ore stockpiles at the mill may be sprayed with water to control
emissions. This apparently represents BAT and is done at Union Carbide's
mill where enough ore is stockpiled to supply the mill during the 6 months
the mine is closed. The addition of water to the ore poses no operational
problems since the ore is milled wet (the ore does not require drying before
being processed) and water is plentiful. Furthermore, the Coalinga,
3-7
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TABLE 3-3. BAGHOUSE EMISSIONS AND COLLECTION EFFICIENCIES
FOR ASBESTOS MILLING!!
Mill
location
Asbestos,
Quebec
Eden Mills,
Vermont
Samp! ing
location
Upstream
Downstream
Upstream
Downstream
Optical microscope
500X
Total
fibers Efficiency
(f/m3) (%)
2.19 x 109
8.33 x 105 99.96
1.42 x 109
4.52 x 104 > 99.99
Electron
16,
Total
fibers
f/m3)
1.24 x 1012
1.44 x 109
1.36 x 10l3
1.29 x 108
microscope
364X
Efficiency
99.88
> 99.99
TABLE 3-4. AMBIENT AIR CONCENTRATIONS OF FIBERS IN THE VICINITY OF
ASBESTOS MILL TAILINGS PILE, COALINGA, CALIFORNIA9
Sampling data3
Approximate sampling
location with respect to
active face of tailings
pile, (m [ft])a
Fiber concentration
by optical microscopy
(f/m3)
conveyor transfer
3 (10) at last
conveyor transfer
224 (736) downwind
224 (736) downwind
9.51 x 105
9.31 x 105
7.31 x 105
Fiber concentration
by electron microscopy
(f/m3)
330 (1,082) upwind
330 (1,082) upwind
3 (10) at last
0.75 x 105
0.86 x 105
7.39 x 105
1.54 x
-
1.58 x
ID8
108
5.93 x 108
a Samples were taken at an elevation of 2 meters (6.6 feet).
3-8
-------
TABLE 3-5. SUMMARY OF AMBIENT ASBESTOS MONITORING DATA IN VICINITIES
OF ASBESTOS MILL, HYDE PARK, VERMONT*?
Emission source
Range of average asbestos
concentrations (yg/m^)
Tailings pile, wet-rock storage,
mill, dryer, conveyors
Primary crushing, conveyor,
wet-ore storage
Dryer, dry rock storage,
crushing, mill
0.03-33.56
5.2-18.81
9.76-24
TABLE 3-6. ESTIMATED TOTAL ANNUAL EMISSIONS FROM ASBESTOS
MILLING IN THE UNITED STATES6»7>8
Source
Mining and milling
Mi 1 1 i ng
Uncontrolled
80% controlled
99% controlled
Milling (80% controlled)
Year
1968
1969
1969
1969
1974
Annual emissions
(metric tons)3
5,110
5,780
1,100
60
1,040
Reference
6
7
7
7
8
a These are engineering estimates only, not precise quantities.
3-9
-------
California, ore is 60 percent asbestos, and emissions from such stockpiles
can be assumed to have a relatively high content of asbestos. Ore from the
other sites contains only 4 to 6 percent asbestos; emissions would probably
contain a similarly low concentration. Because the other mines operate year
round, very little wet ore is stockpiled, typically enough for only 1 or 2
days.
Exterior conveyor belts are typically enclosed or their contents are
wet. Points where conveyors drop waste onto tailings piles are either
exhausted or sprayed with additional water. Conveyor transfer points and
bucket elevators are enclosed and locally exhausted to baghouses.
Crushing, fiberizing, screening, and grading operations are typically
contained under negative pressure; dust-laden air from these processes is
typically exhausted through a single primary baghouse. Cyclone exhausts are
cleaned in baghouses, and dryer exhausts are vented through baghouses, which
frequently use Nomex® fabric filters due to high temperatures of exhaust
gases. High-velocity, low-volume local exhaust ventilation (LEV) is used at
bagging stations to control occupational exposure; dust is exhausted through
a baghouse. Central and portable vacuum equipment is used to clean floors
and around equipment. Control technology used in asbestos milling has not
changed in recent years and still appears to represent BAT.
3.2.5 Waste Disposal
Millions of tons of waste, or tailings, are produced each year by
domestic asbestos milling and are deposited by conveyor belts onto large
tailings piles. They usually are dumped wet onto the piles to prevent
emissions. Attempts to vegetate the surface of tailings piles have met with
limited success due to the high alkalinity of the tailings, which inhibits
plant growth, and the expense of hauling sufficient soil cover in which to
establish vegetation. Chemicals have been added to wet tailings prior to
dumping that help bind the particles and help the tailings resist wind
erosion. Upon drying, some tailings form a protective crust-like cover that
resists erosion and protects underlying material. In some instances,
tailings piles from the milling of long-fiber asbestos ores are
self-stabilizing because of the low percentage of fine dust, the tendency of
meteorological conditions to form a layer of larger particles that protect
3-10
-------
the pile's interior, and the consolidation of the pile by freezing during
much of the year.iO
3.2.6 Costs
Information on control and process costs was not collected during
Phase I.
3.3 ASBESTOS PAPER PRODUCTS
3.3.1 Industry Statistics
Asbestos paper products are used in a wide variety of applications but
have in common their production on papermaking machines. Paper products can
be grouped according to categories in Table 3-7, which also presents, for
each category, asbestos consumption and asbestos paper production. Flooring
felt alone accounts for nearly 50 percent of total asbestos consumed in
paper products. Asbestos consumed by flooring felt, roofing felt, and
beater-add gasketing paper accounts for nearly 90 percent of total asbestos
consumed in asbestos paper products. Production of flooring felt, roofing
felt, beater-add gasketing paper, and specialty paper increased from 1975
to 1979, as shown in Table 3-8. During the same period, total production
was up roughly 10 percent and production of millboard and roll board was
apparently declining.3
Producers of asbestos paper, production location, specific products by
individual plant, and employee information are shown in Table 3-9.
3.3.2 Process Description
Chrysotile is the predominant form of asbestos used in making asbestos
paper, but various binders and fillers may be added to produce desired
properties. Table 3-10 shows typical compositions of various asbestos paper
categories.
The process for making asbestos paper is similar to that for making
wood fiber paper and board. The description below is derived from a study
of the U.S. asbestos paper market.13
Asbestos goes into a pulper or beater and is screened and cleaned to
achieve required properties. The slurry is regulated to a consistency of
1/2 to 1 percent solids and fillers, binders, and other modifiers are added.
A sheet is formed on either a Fourdrinier or cylinder machine and dewatered
3-11
-------
TABLE 3-7. ASBESTOS CONSUMPTION AND PRODUCTION OF ASBESTOS PAPER3
Paper
category
Flooring felt
Roofing felt
Beater-add
gasketing paper
Pipeline wrap
Specialty papers
Millboard and
roll board
Commercial paper
Electrical paper
Total
Asbestos fiber consumed
(short tons)
120,000
90,000
25,000
15,000
6,600
4,500
4,200
1,000
266,300
Production
(short tons)
141,200
138,500
35,700
23,100
7,800
6,000a
4,400
1,050
357,750
a This estimate was especially difficult, given the rapidly declining market
for this product. This figure was reached from consulting previous
studies, contacts with industry representatives, and general knowledge of
the industry.
3-12
-------
TABLE 3-8. UNITED STATES ASBESTOS PAPER PRODUCTS INDUSTRY PRODUCTION,
1975 AND 19793>13
Paper category
Flooring felt
Roofing felt
Beater-add gasketing paper
Pipeline wrap
Specialty papers
Millboard and roll board
Commercial paper
Electrical paper
Total
(
1975
125,000
120,000
30,000
26,000
5,000+a
17,500
b
—
323,500+
Production
short tons)
1979
141,200
138,500
35,700
23,100
7,800
6,000
4,400
1,050
357,750
a Production estimate may be slightly understated since not all specialty
products were included.
b Included in figure for millboard and roll board above.
3-13
-------
TABLE 3-9. PRODUCERS OF ASBESTOS PAPER PRODUCTS3
Total
Producer employees
Alsop Engineering
Mlldale, Connecticut
Armstrong Cork
Fulton, New York
Boise Cascade
(Latex Fiber
Division)
Beaver Falls, New York
Cellulo
Fresno, California
Sandusky, Ohio
Congoleura
Cedar Hurst, Maryland
Ertel Engineering
Kingston, New York
Fllpaco
Chicago, Illinois
GAP
Erie, Pennsylvania
Whitehall, Pennsylvania
H S K Filters
Richmond, California
Holl Ingsworth 4 Vose
E. Walpole,
Massachusetts
Johns-Manville
Manvllle, New Jersey
Waukegan, Illinois
Lydall
(Colonial Fibre)
Covington, Tennessee
Rochester, New Hampshire
N/A
328
102
10
30
303
N/A
N/A
•
154
650
21-22
174
2,000
1,018
132
92
Production Flooring Roofing Gasketlng Pipeline Specialty Millboard/ Commercial Electrical
workers felt felt paper wrap papers rollboard papers paper
N/A X
287 X X
50 X
6-7 X
N/A X
268 X
N/A X
N/A X
N/A X X X XXX
412 X
15 X
90 XX
1,550 X XX X
824 X X X X X
112 X X
64 X
(Continued)
-------
co
i
.TABLE 3-9. PRODUCERS OF ASBESTOS PAPER PRODUCTS3 (Continued)
Producer
Nlcolet
NorMstown,
Pennsylvania
Ambler, Pennsylvania
Qu1n-T
Til ton. New Hampshire
Rogers
Rogers, Connecticut
Jim Walter
(Celotex)
Linden, New Jersey
locklund, Ohio
Total
employees
100-150
143
67
173
45
890
Production Flooring
workers felt
50-75 X
105
47
134
38
725
Roofing Gasketlng
felt paper
X X
•
X
X X
X X
Pipeline Specialty Millboard/ Commercial
wrap papers roll board papers
XX X
X
X
XXX
XXX
Electrical
paper
X
-------
TABLE 3-10. COMPOSITION OF ASBESTOS PAPER PRODUCTS3.13
Product and composition Percent of composition
Asbestos flooring felt
Asbestos 85
Latex 15
Asbestos roofing felt
Asbestos 85-87
Cellulose fibers 8-12
Starch binders 3-5
Beater-add gasketing paper
Asbestos 60-80
Polymer 20-40
Pipe!ine wrap
Asbestos 85
Cellulose and starch binder 15
Specialty paper
Asbestos 85
Cellulose, binder, and filler 15
Commercial asbestos paper and millboard
Asbestos 95-98
Starch filler 2-5
Electrical paper
Asbestos 80-100
Organic fiber 0-20
3-16
-------
to approximately 20 percent by passing over suction boxes. The Fourdrinier
machine uses a travelling screen for sheet formation and is suited for both
high- and low-speed operations, making it preferable for production of
lighter grades or for a variety of grades on a single machine. The cylinder
type uses a rotating vacuum roll for sheet formation and is operated at
lower speeds, making it suitable for producing heavier board grades. Solids
content is increased to 35 to 40 percent by mechanical and vacuum dewatering
on press rolls. Finally, the sheet is dried on dryers such as steam-heated
cans or air dryers to give a solids content of 90 percent or more.
Various finishing operations may be performed at the paper-
manufacturing site or the paper may be transported and finished at other
company-owned sites to reduce transportation costs. The paper product may
be sold unfinished on the open market. Depending on the product, finishing
steps include saturation with asphalt, tar, and resins; vinyl coating;
cutting; and laminating.
3.3.3 Emission Sources
Potential emission sources include storing and warehousing the bags of
asbestos, opening the bags and dumping the fibers into the pul per or beater,
mixing ingredients (although not likely due to the wet conditions), and
slitting the finished stock. Emissions from sheet formation and subsequent
dewatering are unlikely because of the wet state of the product and the
presence of binders that hold the fibers in the product matrix. Finishing
operations, such as saturating with asphalt and tar, are not likely to
produce asbestos emissions. Little asbestos waste is created by asbestos
paper production. However, when wet waste is not removed from floors or
equipment, it may dry out and, if disturbed, release fibers.
Engineering estimates of asbestos emissions from paper manufacture are
not precise. Table 3-11 presents emission estimates based on 1969 asbestos
consumption for paper manufacture from uncontrolled and controlled sources.
Table 3-12 presents emission estimates from paper production based on 1976
asbestos consumption. Estimates in Table 3-12 do not include emissions from
production of roofing felts, insulating paper, or beater-add gasketing paper
due to differences in product classification by the report's authors.
3-17
-------
TABLE 3-11. ESTIMATES OF TOTAL ANNUAL ASBESTOS EMISSIONS FROM
ASBESTOS PAPER MANUFACTURING IN THE UNITED STATES, 19697
Emissions to air
Quantity3
(short tons)
Emissions, if uncontrolled
Emissions, 75% controlled
Emissions, 99% controlled
60
15
0.6
a Based on 1969 asbestos consumption data,
TABLE 3-12. ESTIMATES OF TOTAL ANNUAL ENVIRONMENTAL RELEASES OF
ASBESTOS FROM PAPER MANUFACTURE IN THE UNITED STATES, 1976a14
Emissions
Quantity
(short tons)
Comment
To air:
From baghouse emissions
(99.99% efficient)
To waste dump or landfill:
Rejected product and scrap
Baghouse fines
Process wastewater solids
To water:
From process wastewater
0.014-1.0
Not available
140
283
5.4-11.6
Free-fibers
Small because it can
be recycled
Free-fibers
Fibers matted
together by
binders, but free-
fibers are a
possibility
Free-fibers with some
binders
a Does not include asbestos roofing, insulation, or gasket paper.
are based on 1976 consumption data.
Estimates
3-18
-------
3.3.4 Control Techniques
Emissions from bag opening, dumping, .and mixing are controlled with use
of high-volume, low-velocity LEV. Asbestos may be packaged in pulpable
bags, which can be added to the beater, in some cases alleviating the need
to open bags. In other instances, pulpable bags still must be opened; but
the bags can be put in the slurry, eliminating the problem of storing and
disposing of fiber-contaminated bags. Baghouses and wet collectors are used
to clean exhaust air from the bag opening and mixing area. With the use of
pulpable bags and elimination of bag opening and dumping, fiber release may
be sufficiently low to preclude the need for LEV and subsequent air-cleaning
devices. LEV may be used at the paper slitting step. Trimmings may be
returned pneumatically to the procsss through a mechanical collector; fine
material exhausted from the mechanical collector is exhausted through a
baghouse to the atmosphere. Baghouse and wet collector wastes can be
returned to the process.
Following paper production, various finishing or additional processing
steps may produce the desired product. Examples include polyvinyl coating
for vinyl sheet flooring and asphalt saturation for roofing felt. Very
little fiber is released during these processes and the .only controls
involved are to prevent effluent emissions associated with asphalt, tar, and
solvents.
3.3.5 Waste Disposal
It has been noted that scrap and collection device wastes are often
returned to the process with the result that little solid waste is produced
for disposal; sludge collected from wastewater treatment commonly is
landfilled.
3.3.6 Costs
Cost information for control equipment was not collected during
Phase I.
3.4 ASBESTOS FRICTION MATERIALS
3.4.1 Industry Statistics
Asbestos friction materials include drum brakes, disc pads for disc
brakes, brake blocks, clutch facings, and industrial linings for
manufacturing equipment. The largest segment of asbestos friction material
3-19
-------
shipments by value is drum brake linings (molded and woven drum brake
linings), accounting for nearly 70 percent of the 1977 value of shipments
for all asbestos friction materials.15 In 1972, disc brake pads accounted
for 6.8 percent of shipment value for all friction material shipments.
Although 1977 shipment values for disc brake pads are not available,
shipment values for the disc brake pad segments probably have increased
since 1972 since disc brake systems have replaced drum brake lining systems
on many domestic automobiles.3 The only information available on production
quantities is a combined shipment quantity for disc brake pads and woven and
molded clutch facings of 94 million pieces.15
Table 3-13 lists domestic producers of asbestos friction materials,
plants and their locations, employment information, asbestos and nonasbestos
product line, markets supplied by each manufacturer, and 1979 estimated
sales. Information is incomplete, depending on information withheld by the
company.
3.4.2 Process Description
The general formulation of asbestos friction materials is:
Asbestos: 50 to 80 percent,
Binder: 16 to 45 percent, and
Friction modifiers: 5 percent.16
Brake linings and clutch facings may be manufactured by either a molded
or woven process. The molded process is further characterized by the
"dry-mix" and "wet-mix" processes. The following descriptions are from an
EPA study.17
Manufacturing steps typically used in "dry-mix" molded brake lining
manufacture begin with weighing and mixing in a two-stage mixer the bonding
agents, metallic constituents, asbestos fibers, and additives. The mix is
then hand-tamped into a metal mold, which is placed in a preforming
press that partially cures the molded asbestos sheet. The asbestos sheet is
taken from the preforming press and put in a steam-preheating mold to soften
the resin in the molded sheet. The molded sheet is formed to the proper arc
by a steam-heated arc former, which resets the resin. The arc-formed sheets
are then cut to proper size. The lining is baked in compression molds to
retain the arc shape and convert the resin to a thermoset or permanent
3-20
-------
TABLE 3-13. DOMESTIC PRODUCERS OF ASBESTOS FRICTION MATERIALS3
CO
Company
General Motors
Corporation
Chrysler
Corporation
Bendix
Raybestos-
Manhattan
Abex Corporation
(1C Industries)
Carlisle
Corporation
Auto Friction
Corporation
Plant
Delco-Moraine Division
(Dayton, Ohio)
Inland Division
(Dayton, Ohio)
Trenton Chemical
Green Island, New York
Cleveland, Tennessee
St. Joseph, Michigan
Stratford, Connecticut
Manheim, Pennsylvania
Crawfordsvllle, Indiana
American Brake Blok
Division
(Winchester, Virginia)
Salisbury,
North Carolina
Ridgeway, Pennsylvania
Lawrence, Massachusetts
Empl oyment
Total Production
2,300a
N/A N/A
N/A N/A
497 404
930 684
l,569d 1,219
846°" 657
484d 376
700-1,000 525-750
150 140
425 300
400 300
Product line
Asbestos
Disc brake pads
Clutch facings
and drum brake
linings
Clutch facings
and disc and
dr.um brake
linings
Brake linings
Brake linings
Disc brakes
Brake linings and
disc brake pads
for light and
heavy vehicles;
other friction
material s
Disc pads, drum
brakes, truck
blocks, brakes for
off-the-road
brake blocks
Drum brake linings
for light and
heavy trucks, disc
brakes
Disc and drum
brake linings for
passenger cars and
1 ight trucks
Nonasbestos Market
Disc brake pads and CMC
other auto parts
Delco-Moraine
(GMC)
Chrysler
Friction materials OEM and
after-market
Semlmetallic and
cermet disc brake,
master cylinders
Friction materials OEM and
and brake parts aftermarket
None6 OEM and
aftermarket
None6
Drum brake linings N/A
None6 Aftermarket
1979 estimated
sales
$16.225,000b
(asbestos
friction
materials only)
N/A
J94.555.OOOC
$165,000,000b
(asbestos
friction
materials only)
$66.593.000
$28.. 161, 000
$26,505,000
(Footnotes on last page of table.)
(Continued)
-------
TABLE 3-13. DOMESTIC PRODUCERS OF ASBESTOS FRICTION MATERIALS3 (Continued)
co
i
ro
ro
Company
H. K. Porter
Nuturn
Royal Industrial
Brake Products
(Lear-Siegler)
National Friction
Products
Corporation
Gatke Corporation
Standee Industries
Brassbestos
Manufacturing
Corporation
Thiokol Chemical
Corporation
Plant
Huntington, Indiana
Paulding, Ohio
New Castle, Indiana
Smithville, Tennessee
Danville, Kentucky
Logans Port, Indiana
Warsaw, Indiana
Houston, Texas
Paterson, New Jersey
Trenton, New Jersey
Employment
Total Production
400 200
115
80-100
120
241d 175-200
180 145
180d 150
131 106
120-130 98
147d 114
Product line
Asbestos Nonasbestos
Disc and drum Semlmetal 1 ic disc
brake linings and brakes; nonasbestos
clutch facings clutch facings
for passenger
cars; brake
blocks; heavy duty
brake linings and
industrial parts
Disc pads and
drum brakes for
passenger cars; None6
clutch facings
and truck blocks
Disc and drum None6
brake linings
for passenger cars
and light trucks
Brake linings and None
clutch facings for
off-the-road
vehicles
Friction materials Friction materials
Nonautomotlve None6
brake linings and
clutch facings;
oil-well brake
blocks
Brake linings for None6
passenger cars
and light trucks
Disc brake pads None6
and drum brake
linings for
passenger cars
Market
OEM and
aftermarket
301 OEM
701 aftermarket
Aftermarket
Off-the-road
vehicle manu-
facturers
(tractors, lawn
mowers, etc.)
Aftermarket
Oil companies,
industrial
equipment
manufacturers
Aftermarket
OEM and
aftermarket
1979 estimated
sales
$26.505,000
$21,535,000
$15,969,000
$11,927,000
$11,927,000
$8,680,000
$8,283,000
$9,740,000
(Footnotes on last page of table.)
(Continued)
-------
TABLE 3-13. DOMESTIC PRODUCERS OF ASBESTOS FRICTION MATERIALS3 (Continued)
co
t
ro
co
Employment
Company Plant
Wheeling Brake Bridgeport, Ohio
Block
Lasco Brake Oakland, California
Products
Total
61
58d
Production
51
40.-50
Product
Asbestos
Brake linings for
off-the-road
vehicles
Disc and drum
brake linings
line
Nonasbestos
None6
Nonasbestos
friction materials;
Market
Distribution,
mining, and
construction
companies; all
for replacement
After-market
1979 estimated
sales
$4,042,000
$3,843,000
Molded Industrial
Friction
Corporation
Scan-Pac
Manufacturing
Company
Reddaway
Manufacturing
Company
Prattville, Alabama
Menomonee Falls,
Wisconsin
Newark, New Jersey
54d 42 Brake linings for
tractors
40-45 33-38 Brake linings for
off-the-road
nonautomotive use
31 22 Brake linings for
Industrial, non-
automotive uses
manufacture other
nonasbestos products
None (plant in
Kentucky manufac-
turers nonasbestos
linings)
None
$3,578,000
Primary manu-
facturers of
lawn mowers,
snow mobiles, etc.
Primary manu-
facturers of
elevators and
washing machines
$2.816,000
$3,000,000°
Red ford
Auto Specialties
Manufacturing
Corporation
National Brake
Block
Boston. Massachusetts
St. Joseph, Michigan
Mobile, Alabama
15 14 Brake linings for-
passenger cars and
light trucks
10d 8 Brake linings for
tractors and
combines
6d 3-6 Brake linings for
passenger cars
None Guardian
Corporation
(assemblers)
No substitute frlc- OEM In farm
tion materials; machinery
other auto parts
produced (plant has
total of 185 employees)
None After-market
$994,000
$663,000
$398,000
Borg-Warner Corporation^
N/A: Company would not supply Information.
a Only a fraction of these workers are involved in friction material manufacture.
b This estimate, of 1979 sales of asbestos friction materials, was supplied by the company.
c This estimate is understated because Bendix would not supply employment figures for the New York plant.
d Total employees were estimated from the number of production employees (supplied by plant personnel) by applying an average ratio of production workers
to total employment. The ratio was calculated from plants from which both production and total employment figures were available.
e Plans to produce nonasbestos friction materials.
f No Information provided.
-------
condition, finished, inspected, and packaged. Finishing steps include
sanding and grinding of both sides to correct thickness, edge grinding, and
drilling holes for rivets. Following drilling, the lining is vacuum
cleaned, inspected, branded, and packaged.
"Wet-mix" process is a misnomer, because the molded lining ingredients
are relatively dry. The designation "wet-mix" arises from solvent use in
production.
After the ingredients are weighed, they are combined in a sigma blade
mixer and are then sent to grinding screens where the mixture's particle
size is corrected. The mixture is conveyed to a hopper where it is forced
into the nip of two form rollers that compress the mixture into a continuous
strip of friction materials. The strip is cut into proper lengths and
arc-formed on a round press bar, each operation by separate units. The
linings are then placed in racks and either air dried or oven dried to
remove the solvent. An alternative is to place the arc-formed linings in
metal molds for oven baking. From the ovens, the linings are finished,
inspected, and packaged.
Molded clutch facings are produced in a manner similar to the wet-mixed
process. The rubber friction compound, solvent, and asbestos fibers are
placed in a mixer churn, and the mixture is conveyed to a sheeter mill that
forms a sheet or slab of the materials. The sheet is then diced by a rotary
cutter into small pieces, which are placed in an extrusion machine that
forms sheets of the diced material. The sheets are cut into proper size and
punch-pressed into doughnut-shaped sheets; scraps are returned to the
extrusion machine. The punched sheets are placed on racks and sent to a
drying oven and then to a baking oven for final curing and solvent
evaporation. The oven-dried sheets are sent to the finishing operations.
Woven clutch facings and brake linings are manufactured of high-
strength asbestos fabric frequently reinforced with wire. The fabric is
predried in an oven or by an autoclave to prepare it for impregnation with
resin. The fabric can be impregnated with resin by several techniques:
Immersion in a bath of resin,
Introducing the binder into an autoclave under pressure,
3-24
-------
Introducing dry impregnating material into carded fiber before
producing yarn, and
Imparting binder into the fabric from the surface of a roll.
After the solvents are evaporated from the fabric, the fabric is made into
brake linings or clutch facings. Brake linings are made by calendering or
hot pressing the fabric in molds. The linings are then cut, rough ground,
placed in molds, and placed in a baking oven for final curing. Following
curing, the lining is finished, inspected, and packaged.
In the manufacture of woven clutch facings, the treated fabric is cut
into tape-width strips by a slitting machine. The strips are wound around a
mandrel to form a roll of the fabric. The roll is pressed in a steam-heated
press and then baked in an oven to cure the resin in, the clutch facing.
Following the curing, the clutch facing is finished, inspected, and
packaged.
The friction products industry is a mature one with only marginal changes
occurring in the production processes over the years; older plants are labor
intensive as opposed to capital intensive.18
3.4.3 Emission Sources
Potential sources of asbestos emissions in friction materials
manufacture include the unloading and warehousing of palletized bags,
weighing, bag opening, charging of mixers, blending of ingredients,
discharging of mixers, forming or rolling, curing, and finishing operations.
Finishing operations generate large quantities of asbestos-containing
dust.!0
Emissions from these sources are collected using LEV and exhausted to
fabric filters or wet collectors. Disposal of waste dust from collection
devices is another potential emission source. Wastewaters from wet
collectors are held in settling ponds; settled material occasionally is
dredged from the pond and is another potential emission source upon drying.
Emission concentration data for friction material manufacturers were not
available. However, various estimates have been made of total annual
emissions and are presented in Tables 3-14, 3-15, and 3-16. These estimates
are not precise and project only a general magnitude of release. Estimates
in Table 3-14 are based on a series of estimates of collection efficiency.
Estimates in Table 3-15 are, in most instances, based on emission estimates
3-25
-------
TABLE 3-14. ESTIMATES OF TOTAL ANNUAL ASBESTOS EMISSIONS FROM
FRICTION MATERIAL PROCESSING IN THE UNITED STATES7
Quantity
Emissions to aira (metric tons/yr)
Emissions, if uncontrolled 5,711
Emissions, 95% controlled 286
Emissions, 99% controlled 57
a Based on 1969 asbestos consumption.
TABLE 3-15. ESTIMATES OF TOTAL ANNUAL ASBESTOS EMISSIONS FROM
FRICTION PRODUCT MANUFACTURING IN THE UNITED STATES8.19
Quantity
Emissions to air (metric tons)3
From process 18
From disposal 36
a Based on 1974 asbestos consumption.
3-26
-------
TABLE 3-16. ESTIMATES OF TOTAL ANNUAL ENVIRONMENTAL RELEASE OF
ASBESTOS FROM FRICTION MATERIAL MANUFACTURE IN THE UNITED STATES14
Emissions3
Quantity
(short tons)
Comment
To air:
Baghouse emissions
Air scrubber emissions
To waste dump or landfill:
Baghouse fine and product scraps
Wastewater solids from air
scrubbers
To water:
Wastewaters from air scrubbers
0.61-6.0 Free-fibersb
0.14 Free-fibers'3
8,130
6.7
0.3
Mostly free-fibers15
Wet free-fibers^
Free-fibers13
a Based on 1976 asbestos consumption.
b These "free-fibers" may be coated with resin; however, "free" indicates a
potentially respirable fiber.
3-27
-------
from individual plants, production rates, number of fibers per unit of
weight, and extent of control present in the asbestos industry;8 the limit
of accuracy is an order of magnitude.8,19 Emissions to air given in Table
3-16 were estimated similarly; the smaller number for baghouse emissions was
calculated using a materials balance approach.14
3.4.4 Control Techniques
There has been no apparent change in BAT in the friction products
industry. LEV systems are employed extensively in the manufacture of
friction materials. Captured air typically is exhausted through baghouses,
although wet collectors are used in a few plants.1? Central vacuum-cleaning
systems are also used for in-house cleanup around the various operations.
These units use fabric filtration for cleaning exhaust air. To help control
emissions from the process of removing waste from baghouses for disposal,
some manufacturers of friction materials convey (pneumatically or by screw
conveyor) baghouse waste to a device that, through the addition of water,
converts the waste to small pellets. Such pellets can be handled more
easily without the dust problem of loose baghouse waste.^0
3.4.5 Waste Disposal
Friction material waste consists of rejects, material collected in
baghouses, vacuum cleaner waste, dredged solids from wastewater settling
ponds, empty asbestos bags, baghouse bags, and disposable personal
protective equipment. Wastes are typically disposed of in landfills.
Plants either dispose of waste themselves on their own property or contract
with a private waste-handling company for waste transport and disposal.
Waste disposal sites may be either publicly (municipal or county) or
privately owned and operated. As discussed above, baghouse waste may be
pelletized to facilitate handling and dust control. Recycling of friction
material waste back into the manufacturing process is not commonly
practiced.
3.4.6 Costs
Information on control equipment and process costs was not collected
during Phase I.
3-28
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3.5 ASBESTOS-CEMENT PRODUCTS
3.5.1 Industry Statistics
Asbestos/cement (A/C) products manufactured in the United States
usually fall under one of two categories: sheet or pipe. However, a small
market exists for A/C molded and extruded products. Six U.S. manufacturers
produce A/C products, of which Johns-Manville, Cement Asbestos Products
Company (a subsidiary of Asarco), and CertainTeed Corporation produce A/C
pipe; and Johns-Manville, International Building Products (formerly National
Gypsum), Nicolet, and Supradur produce A/C sheet.
The six manufacturers employ approximately 3,100 workers, which is
about 20 to 25 percent of total employment in the asbestos manufacturing
industry. Employment characteristics for each of the A/C pipe and sheet
manufacturers and their plant locations are summarized in Tables 3-17 and
3-18, respectively.21,22 individual plant production quantities were not
available.
In 1977, shipment value of A/C pipe, conduit, and ducts was $215
million, approximately 25 percent of total value of the asbestos industry
market. The 1977 shipment value for A/C sheet was $52 million,
approximately 5.4 percent of the value for all asbestos products.21
Since 1969, asbestos consumption by the A/C industry has fluctuated
between 148,000 and 288,000 metric tons with 1980 consumption (152,000
metric tons) the lowest reported except for 1976 consumption. Overall
asbestos demand within the pipe industry stayed relatively stable until
1980, as opposed to a steady decline in demand in the sheeting industry.
Table 3-19 presents U.S. asbestos consumption in the A/C industry and total
U.S. consumption for the period from 1969 to 1980.1»21
The A/C pipe market share of water and sewer pipe has declined slightly
due to availability of substitute materials and citizen concern over
possible release of asbestos fibers into water systems.23 Although the
demand for A/C sheet has declined due to the introduction of substitutes,
further decline is not likely without performance improvements among
substitutes or a large increase in cost of A/C sheet.23
In 1977, the Bureau of Mines projected U.S. demand for asbestos in the
year 2000 was 274,000 short tons for the pipe industry and 116,000 short
3-29
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TABLE 3-17. PRODUCERS OF A/C PIPE21.22
Producer and location
Total
empl oyees
Product line
Asarco, Inc.
Cement Asbestos Products
Company
Ragland, Alabama
CertainTeed Corporation
Santa Clara, California
Riverside, California
Ambler, Pennsylvania
Hillsboro, Texas
Johns-Manville Corporation
Denison, Texas
Long Beach, California
Stockton, California
140
140
115
165
180
204
362
247
A/C pipe
A/C pipe
A/C pipe
A/C pipe
A/C pipe
A/C pipe and polyvinyl
chloride pipe
A/C pipe
A/C pipe and polyvinyl
chloride pipe
3-30
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TABLE 3-18. MANUFACTURERS OF A/C SHEET PRODUCTS2!
Producer and location
Total
employees
Product line
Johns-Manville
Nashua, New Hampshire 86
Waukegan, Illinois 1,018
International Building
Products (formerly
National Gypsum)
New Orleans, Louisiana 200
Ni colet
Ambler, Pennsylvania 143
Supradur
Wingap, Pennsylvania 125-130
A/C sheet products only
A/C sheet and asbestos
papers
A/C flat and corrugated
sheet; siding
A/C flat sheet; asbestos
millboard and roll board;
compressed asbestos
gasketing
A/C roofing and siding
3-31
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TABLE 3-19. U.S. CONSUMPTION OF ASBESTOS IN A/C
INDUSTRY COMPARED TO TOTAL U.S. CONSUMPTION, 1969-198Q1*2
(Thousand metric tons)
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
Asbestos
pipe
135
126
131
140
151
202
139
127
145
217
213
144
Cement
sheet
50
46
48
52
58
86
40
21
40
36
11
8
Total
cement
products
185
172
179
192
209
288
179
148
185
253
224
152
Total U.S. consumption
711
666
689
734
795
768
552
659
610
619
560
359
3-32
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tons for the sheet industry.24 The 1980 projections show a change in
expected asbestos demand for the year 2000: the pipe industry is expected
to consume 210,000 metric tons and asbestos will no longer be used in the
sheet industry.^
3.5.2 Process Description
In the United States, A/C products are made from varying amounts of
asbestos, cement, and silica. On a weight basis, A/C pipe normally contains
from 15 to 25 percent asbestos, 42 to 53 percent Portland cement, and 34 to
40 percent finely ground silica.21 The A/C products may have an asbestos
content range of 10 to 70 percent, but such extremes are used for specialty
items only.25 Chrysotile is the principal type of asbestos used in A/C
pipe. In 1980, 83.13 percent of asbestos used in A/C pipe was chrysotile,
16.74 percent was crocidolite, and 0.13 percent was amosite
(cummingtonite-grunerite asbestos).21 up to 6 percent of finely ground
solids from damaged pipe also are used by some plants as filler material.25
The average asbestos content of A/C pipe, by weight, has been calculated at
about 18 percent. An average asbestos content of 25 percent has been
reported,26 while another report stated that asbestos content is normally
below 20 percent.27 Grades of asbestos-fiber commonly used for A/C pipe are
4 and 5.21
Nearly all asbestos presently used in A/C sheet is chrysotile; a small
amount of amosite and anthophyllite asbestos is used also. A/C sheets
contain 12 to 35 percent asbestos, 45 to 54 percent cement, and 30 to 40
percent silica.27 Grades 4, 5, and 6 commonly are used in A/C sheet.21
Manufacturing processes for A/C pipe and sheet may vary slightly from
plant to plant, but the overall processes are the same. In general, the
method used to make A/C pipe and A/C sheet is similar to methods used to
make asbestos paper and asbestos millboard. Also, A/C processes can be wet,
dry, molded, or extruded.
The following description of the basic process for pipe manufacture is
reproduced- here from an EPA document.25
"After thorough blending of the raw materials, the mixture is
transferred to a wet mixer or beater. Underflow solids and water from
the save-all are added to form a slurry containing about 97 percent
3-33
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water. After thorough mixing, the slurry is pumped to the cylinder
vats for deposition onto one or more horizontal screen cylinders. The
circumferential surface of each cylinder is a fine wire mesh screen
that allows water to be removed from the underside of the slurry layer
picked up by the cylinder. The resulting layer of asbestos-cement
material is usually from 0.02 to 0.10 inch in thickness. The layer
from each cylinder is transferred to an endless felt conveyor to build
up a single mat for further processing. A vacuum box removes
additional water from the mat prior to its transfer to mandrel or
accumulator roll. This winds the mat into sheet or pipe stock of the
desired thickness. Pressure rollers bond the mat to the stock already
deposited on the mandrel or roll and remove excess water. Pipe
sections are removed from the mandrel, air cured, steam cured in an
autoclave, and then machined on each end."
Although the general description may apply to all A/C processes,
differences often exist in methods of fiber opening, raw material mixing,
and product forming. For example, raw materials usually are blended dry
after fiber opening in a willow or a similar device. However, fiber opening
and blending of raw materials can be achieved using wet methods.
A/C sheet is manufactured using either a dry process, a wet process, or
a wet mechanical process. In the dry process, raw materials are dry mixed,
and the mixture is spread evenly over a moving belt, sprayed with water, and
compressed by rolls to required thickness. The moving sheet is cut to
desired sizes and shapes and is autoclaved. The dry process is generally
used for shingle and siding products. Flat or corrugated sheets are
produced in the wet process by introducing the A/C slurry into a mold and
hydraulic press. The slurry is squeezed to remove water from the mold. The
sheet is ejected from the mold and cured as in other A/C products. The wet
mechanical process is similar to the process for making A/C pipe, except the
A/C material on the accumulator roll is slit across the roll to produce a
sheet.
Molding processes are used to make small, irregularly shaped A/C
products. This process and the extrusion process are limited to speciality
products.
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3.5.3 Emission Sources
Asbestos emission sources and their number are determined by process
design. Both wet-mix and dry-mix processes have in common eight emission
sources of asbestos fiber: unloading and storage of asbestos fibers, bag
opening and dumping, fiber opening, weighing, transferring, blending of raw
materials, dust collection, solid waste, and wastewater disposal. Unloading
asbestos involves use of forklifts to remove pallets of bags containing
asbestos from rail cars or trucks. Asbestos pallets are usually unitized;
i.e, wrapped in plastic to help prevent damage to bags during transport.
Mixing is an additional emission source in processes that use dry mixing.
This emission source is absent in processes that wet mix raw materials. In
addition, wet-mix processes open fibers and blend raw materials in a slurry,
thus eliminating two emission sources common to dry mixing.
Disposal of asbestos fibers removed by LEV and filtering devices and
not recirculated into the production process may be an emission source
depending upon precautions taken in containing fibers during transportation
and at the disposal site. Disposal of A/C solids dredged from process
wastewater settling ponds is also a potential asbestos emission source.
Finishing operations also produce emissions. However, it has been
reported that 90 percent of the fibers with aerodynamic diameters less than
7 micrometers produced by cutting, grinding, buffing, and other finishing
steps differ from pure asbestos fibers.28
Attempts have been made to characterize asbestos emissions from various
industries, but few data on fiber emissions have been reported.29 The
majority of studies that characterize asbestos fibers and airborne
concentrations are concerned with evaluating occupational hazards. However,
there are two references in which asbestos fiber emissions from several
sources including A/C processors have been estimated. In a 1971 study, it
was estimated that 825 tons of fiber per year are emitted nationwide from
uncontrolled A/C plants and 8.3 tons per year from controlled A/C plants
(assuming 99 percent collection efficiency)-'7 These estimates were based on
use of 1969 asbestos consumption data to calculate an emission factor for
uncontrolled sources of 4 pounds of fiber per ton of asbestos consumed. In
3-35
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a 1975 study, an emission factor of 1 pound per ton from controlled emission
sources in the A/C industry was estimated.30
In both studies cited above,?»30 emission rates are engineering
estimates and are not accurate.29 However, the two studies demonstrate that
emission rates may be reduced significantly by application of appropriate
and adequate controls.29 The numbers reported in both studies suggested
relative emission rates of various sources.29 Emissions from the A/C
industry and asbestos paper and floor tile are low, relative to emissions
from textiles, friction products, mining and milling, and consumptive users
of asbestos.29
In 1974, EPA determined fiber counts and removal efficiencies for control
equipment used in the industry.11 The Agency also determined size
distribution and fractional removal efficiences of collected asbestos
fibers11 (see Tables 3-20 and 3-21). The EPA study showed that the number
of fibers less than 1.5 micrometers emitted is greater than the number of
fibers larger than 1.5 micrometers emitted. The study also determined that
collection efficiency for smaller fibers was slightly lower than that for
larger fibers. It was concluded that the greater number of small fibers
emitted was due to a large concentration of small fibers caught by the LEV
system rather than a low baghouse collection efficiency.11 However, due to
the low removal efficiency of one piece of demonstrated control equipment,
the authors of the report had to qualify this conclusion by claiming a
possible error in sampling the A/C pipe plant emissions.
A National Institutes of Health (NIH) study19 reported emission
estimates from processing asbestos for A/C pipe and sheet products based
upon 1974 production data and EPA's data11 on baghouse emissions. These
estimates reproduced in Table 3-22 were calculated from algorithms derived
in an unpublished report.^ An emission factor of 0.1 kilogram of fiber
emissions per metric ton of processed asbestos was calculated for A/C pipe
and for A/C sheet.8 This emission factor was compared with another of 0.5
kilogram per metric ton based upon 1968 data and reported by Anderson in
1973. The emission reduction was attributed to substantial improvements in
control technology since 1968.8
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TABLE 3-20. BAGHOUSE EMISSIONS AND FIBER REMOVAL
EFFICIENCIES FROM A/C PIPE PLANTS, 1974H
Optical microscope Electron microscope
Total fiber Total fiber
emissions emissions
>1.5 micrometers <1.5 micrometers
Plant sampling (number of (number of
location fibers) % efficiency fibers) % efficiency
Denison, TX
Upstream 1.02 x 10& 3.20 x 10?
Downstream 2.88 x 104 97.18 1.38 x 107 57.90
Waukegan, IL
Upstream >1010 >1014
Downstream 6.37 x 103 >99.99 1.08 x 107 >99.99
3-37
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TABLE 3-21. SIZE DISTRIBUTION AND FRACTIONAL REMOVAL EFFICIENCIES
FROM TWO A/C PIPE PLANTS1!
Size distribution
(wn)
>30
20-30
10-20
1.5-10
0.54-1.5
0.36-0.54
0.18-0.36
0.06-0.18
99.99
>99.99
>99.99
>99.99
>99.99
>99.99
>99.99
100
100
TABLE 3-22. ESTIMATES OF TOTAL ANNUAL EMISSIONS FROM PROCESSING
ASBESTOS FOR A/C PIPE AND SHEET PRODUCTS IN THE UNITED STATES8>19
Emissions to air (metric tons)3
Product From processs From disposal
A/C pipe
A/C sheet
20
9
101
43
aBased on 1974 asbestos consumption.
3-38
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In 1978, EPA published estimates of asbestos emissions to disposal
sites, to water, and to air from A/C pipe and sheet manufacturing sources
based upon engineering assumptions. As in earlier studies, the EPA study
noted that data required to calculate actual emissions were not available.
EPA's published estimates provide only a general magnitude of asbestos
release. These estimates are reproduced in Table 3-23 and Table 3-24.
3.5.4 Control Techniques
Wetting of raw fiber may be the simplest control technique. However,
wetting methods must be compatible with process design and must not alter
product specifications. Asbestos fiber emissions from mixing, fiber
opening, and blending can be controlled by wet process methods. However,
such methods are not commonly employed in A/C pipe manufacture. Also,
emissions from some finishing operations can be controlled by wet dust
suppression systems.
Engineering measures are generally chosen to control asbestos emissions
in the A/C manufacturing industries. Extensive use of LEV to control
occupational exposures and use of fabric filtration to control atmospheric
emissions are common practice in A/C product manufacturing and represent
BAT.
An estimated 95 percent of controls in asbestos manufacturing and
fabricating operations are by exhaust ventilation. The air-cleaning device
most used in conjunction with LEV, central vacuum systems, and air-cooling
and heating systems is the baghouse. A survey of the asbestos industry in
1973 and 1974 showed that 80 percent of the plants used baghouses, 90
percent of control devices in place were baghouses, 4 percent of the
plants used a combination cyclone and baghouse, and 3 percent of the control
devices were a cyclone-baghouse combination.H In a 1976 study of
the efficiency of asbestos baghouse filters, it was concluded that for
all fabrics and values of the baghouse operating parameters tested, the
mass efficiencies of asbestos collection exceeded 99.99 percent.31
Baghouses in conjunction with local exhaust systems, operation
enclosures, enclosed screw conveyors and belt conveyors, and pneumatic
conveyors commonly are used to control fiber emissions from bag-opening
3-39
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TABLE 3-23. ESTIMATED TOTAL ANNUAL ENVIRONMENTAL RELEASE OF
ASBESTOS FROM A/C PIPE MANUFACTURE IN THE UNITED STATES14
Emissions
Quantity
(short tons)3
Comments
To waste, dump, or landfill:
Rejected pipe and scrap
Baghouse fines
Process wastewater solids
To water:
From process wastewater
To air:
From baghouse emissions
10,680
737
480
11-12.5
0.1-2.2
Fibers bound in cement matrix
Free-fibers
Fibers bound in cement matrix
Fibers coated with cement
Free-fibers
aBased on 1976 asbestos consumption.
TABLE 3-24. ESTIMATED TOTAL ANNUAL ENVIRONMENTAL RELEASE OF ASBESTOS
FROM A/C SHEET MANUFACTURE IN THE UNITED STATES14
Emissions
Quantity
(short tons)3
Comments
To waste, dump, or landfill:
Rejected sheet and scrap
Baghouse fines
Process wastewater solids
To water:
From process wastewater
To air:
From baghouse emissions
1,525 Fibers bound in cement matrix
105 Free-fibers
74 Fibers bound in cement matrix
1.9 Fibers coated with cement
0.01-1.5 Free-fibers
aBased on 1976 consumption.
3-40
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operations; from fiber opening, weighing, and blending operations; and from
conveying fiber prior to adding water to the A/C mix.
Emissions are controlled by maintaining storage bins and workspace
under negative pressure and by exhausting air through a baghouse. However,
emissions will not be kept to the minimum if such air-cleaning devices are
not maintained at optimal performance. Makeup air provided to the work
spaces must be cleaned to prevent employee exposure to airborne toxic
substances.
Central vacuuming systems exhausted through baghouses and portable
systems with filtering devices are used extensively to clean spills from
broken bags; dust accumulations around grinding, lathing, and other
machining operations; and dust accumulations on employees' clothes.
Procedures that eliminate the need for sweeping considerably reduce employee
exposure to asbestos fiber and potential for atmospheric emissions.
The 1973-1974 survey of the asbestos industry showed that scrubbers
were used by nearly 7 percent of the plants (but only 2 percent of the
control devices were scrubbers) and that cyclones alone were used in 4
percent of the plants (but only 2 percent of the control devices were
cyclones used alone) .H Cyclones were being replaced rapidly by
baghouses.1!
Current control measures also include returning fiber collected by LEV
and baghouses to the process. This is becoming an integrated process in the
A/C industry. In addition, some processes have been designed or are being
designed to accept fiber filtered from underflow, thereby reducing asbestos
content of wastewater.
In Chapter 5 of this report, additional and more specific information
will be provided regarding control equipment, such as filtering devices,
scrubbers, and electrostatic precipitators. In addition to engineering
control techniques, Chapter 5 provides information on asbestos substitutes,
including those presently available for cement pipe and sheeting products.
3.5.5 Waste Disposal
A/C product waste consists of broken, unusable pieces; material
captured by LEV and central vacuum systems and subsequently captured by
baghouses; portable vacuum cleaner waste; process wastewater solids that
3-41
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have been dredged from a settling pond; and asbestos fibers remaining in
wastewater. Waste also includes empty bags that contained asbestos fibers
and throwaway personal protectiva clothing.
Waste disposal procedures include loading waste onto a vehicle for
transport to a landfill that may or may not be owned by the manufacturing
company. Waste may be transported by the manufacturer or hauling may be
contracted to another company.
Current waste disposal procedures minimize emissions by handling
baghouse dust in plastic bags. Putting empty asbestos bags into other
plastic bags directly after opening and dumping helps to control asbestos
emissions. One A/C plant puts its empty asbestos bags into another large
plastic bag and then puts the whole package into the autoclave prior to
disposal. This acts to shrink wrap the empty asbestos bags and "lock in"
the asbestos. It also reduces the volume of solid waste.
3.6 VINYL-ASBESTOS FLOOR TILE
3.6.1 Industry Statistics
Vinyl asbestos (V/A) floor tiles are manufactured from filled polyvinyl
chloride polymers or copolymers and produced in squares usually 9 inches x 9
inches or 12 inches x 12 inches with thicknesses varying from 1/32 to 3/32
inch. They are widely used because of ease of installation and maintenance,
durability, and rot resistance. Tiles are fastened down with asphalt-based
adhesives or a self-sticking adhesive, which is put on at the manufacturing
facility and covered with release paper.32
V/A floor tiles are manufactured by 7 companies at 14 sites.
Producers, production location, and employment information are listed in
Table 3-25. Employment figures indicate that Armstrong Cork, Kentile
Floors, and GAP are the largest V/A floor tile producers. American Biltrite
is closing one of its facilities.
In 1977, approximately 122 million square yards of V/A floor tile were
produced.33 This production figure includes asphalt floor tile, which was
not reported separately for 1977; however, in 1972 asphalt floor tile
production amounted to 9.8 million square yards.33 The value of V/A and
asphalt floor tile shipments was about $232 million in 1977, up from about
3-42
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TABLE 3-25. PRODUCERS OF V/A FLOOR TILE3
Producer and
location
Production Total
workers employees
Product
line
American Biltrite
(Amtico Tile)
Trenton, NJ
Plant #1
Plant #2
Armstrong Cork
Company3
South Gate, CA
Kankakee, IL
Jackson, MS
Lancaster, PA
Flintkote Corporation
Los Angeles, CA
Chicago, IL
GAP Corporation
Long Beach, CA
Vails Gate, NY
Kentile Floors
Brooklyn, NY
Chicago, IL
Uvalde Rock Asphalt
Houston, TX
Winburn Tile
Manufacturing
Company^
190-200
2,700
88
60
117
200
352
405
N/A
175
90
250
3,600
123
80
201
470
514
491
N/A
200
Administrative offices;
plant in process of
phased shutdown
V/A floor tiles only
V/A floor tile and
other products
V/A floor tiles only
V/A floor tiles only
V/A floor tiles
V/A floor tiles; small
quantity of product
substitutes
Ceramic-mosaic tile and
V/A tile
a Armstrong Cork estimated 1,000 to 1,050 production employees involved in
production of V/A floor tiles.
b Two-thirds of sales volume generated by ceramic-mosaic tile.
3-43
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$208 million in 1972. About $9 million of the total 1972 shipment value,
$208 million, was attributable to asphalt floor tile. Bureau of Mines
information on asbestos consumption is not disaggregated sufficiently to
determine the amount of asbestos consumed in V/A floor tile.
V/A floor tile competes with vinyl-sheet roll goods, solid vinyl floor
tile, ceramic tile, carpeting, and wood.3 information on shipment value in
constant dollars indicates a fairly stable market for V/A floor tile,
although periods of negative and positive growth have occurred.3
3.6.2 Process Description
Information presented here on manufacturing V/A floor tile is from
a manufacturer1s product bulletin.33
Grade 7 chrysotile is used in the manufacture of V/A floor tile.
Formul ations are:
Asbestos:' 5 to 20%,
Binder: 15 to 20%,
Limestone: 53 to 73%,
Plasticizer: 5%, and
Stabilizer: 2%.
Asbestos is received in polyethylene film bags, which can be introduced
unopened into a Banbury or Baker Perkins-type mixer. The other ingredients
are added at this step and mixing proceeds at about 150 °C (300 °F) until a
coherent mass is obtained. The hot material is transferred to a two-roll
mill where the two heated, horizontal, rotating steel cylinders mix the
material further and blanket it out to desired thickness, usually 1 to 2
inches. Chips of contrasting colors can be added at the end of the milling
operation to create a marblized or veined pattern as the slab is processed
further. The slab is passed through a series of calender rolls to bring it
to the desired finished product thickness.
After leaving the calenders, the hot material is partially cooled by
water spray and a wax solution is applied. Further cooling by air is
necessary before dye cutting to minimize shrinkage after cutting. Embossing
is done before cutting when the material is soft enough to take the pattern.
Scrap and rejected tile are reworked and returned to the mixer for
recovery.
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3.6.3 Emission Sources
, Fiber receiving and storage, opening bags, dumping the fibers into the
mixer, mixing, and chopping waste for recycling represent potential emission
sources in V/A floor tile production. The potential for fiber release is
reduced substantially once the ingredients have been worked into a hot,
homogenized plastic mass.
Asbestos emission sampling and analysis have not been performed for V/A
floor tile plants. Engineering estimates of annual, nationwide emissions
are shown in Table 3-26. These quantities cannot be considered precise and
are presented here for completeness. A 1978 report^ estimated annual
emissions of 0.0207 metric ton (0.0227 short ton) based on 1976 Bureau of
Mines asbestos consumption figures for the flooring product category.
However, this category also includes asbestos felt under! ayment, so the
0.0207-metric ton emission estimates are over what the figure should be.
3.6.4 Control Techniques
Floor tile manufacturers use LEV and routine floor cleaning to control
asbestos. Because the mixing and forming steps do not cause significant
asbestos fiber loss, the fiber introduction step (for opened bags)
represents the prime concern for controlling emissions. Dust capture hoods
are applied at bag opening, and dust is commonly exhausted to fabric
filters. The material-handling equipment, including mixers, is kept under
negative pressure with exhaust air directed to a fabric filter. Scrap
material is conveyed to an isolated or enclosed area where automated
choppers process scrap into chips; this operation usually is exhausted
locally to a baghouse.34
3.6.5 Waste Disposal
Trimmings and rejected tile squares are chopped up and reused.
Therefore, only minor manufacturing scraps are disposed to landfills.14
3.6.6 Costs
No control or operations costs were collected during Phase I.
3.7 ASBESTOS-REINFORCED PLASTICS
3.7.1 Industry Statistics
Asbestos-reinforced plastics are polymeric materials to which asbestos
fibers are added to modify the composite's physical and chemical
3-45
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TABLE 3-26. ESTIMATES OF TOTAL ANNUAL EMISSIONS FROM V/A
FLOOR TILE MANUFACTURE IN THE UNITED STATES, 19697
Emission quantity
Emissions (metric tons)
Uncontrolled 366
75J controlled 92
99% controlled 4
3-46
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characteristics. These composite materials are multicomponent blends in
which the asbestos fiber is the load-carrying member and the polymeric
matrix fills the gaps between the fiber and distributes the applied stress
to the fibers. The plastic material provides a shape and a smooth surface
to protect the fibers and also may provide thermal or electrical resistance.
Asbestos fibers are used to reinforce phenolic, polyester, and epoxy resins
and in a wide range of thermoplastic polymers.35
Primary applications of asbestos-reinforced plastics are V/A and
asphalt floor tiles, friction materials, and gasketing,3 discussed
separately in sections specific to these product categories. Phenolic
molding compounds are the major asbestos users in reinforced plastic
applications other than the above primary appl ications.3 In this section,
discussion is limited to phenolic molding compounds.
Major markets for phenolic molding compounds are automotive, printing,
household appliances, and electronics. Other markets include wiring
devices, communications, and closures.34 Producers of asbestos phenolic
molding compounds and employment information are listed in Table 3-27.
Data on quantity and value of product shipments for asbestos-reinforced
phenolic compounds are not compiled by the Bureau of the Census. Data on
asbestos consumed in plastics (other than in flooring, gasketing, and
friction materials) are collected by the Bureau of Mines. Consumption of
asbestos in plastics for the years 1978 through 1980 is presented in Table
3-28. Asbestos consumption in plastics declined 40 percent between 1978 and
1979 and 55 percent between 1979 and 1980. The market for asbestos phenolic
molding compounds is characterized by decreased production, exit from the
industry, and increased production and use of substitutes.3
3.7.2 Process Description
Chrysotile, primarily the Group 7 fibers, is used in the manufacture of
asbestos-reinforced plastics. Although manufacture of asbestos-reinforced
plastics varies, the following description, summarized from a 1976 report,35
is common to most producers of asbestos-reinforced plastics.
In the fiber-opening stage, bags of asbestos are normally opened
manually, and the contents are dumped into a storage hopper and subsequently
conveyed to the dry blending stage. Alternatively, asbestos may be dumped
3-47
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TABLE 3-27. MANUFACTURERS OF ASBESTOS-REINFORCED
PHENOLIC MOLDING COMPOUNDS3
Manufacturer and
location
Production
workers
Total
employees
Product
line
PI asl ok
Buffalo, NY
Lock port, NY
N/A
50
Plastics Engineering
Sheboygan, WI
Reichhold Chemicals,
Incorporated
Carteret, NJ
Resinoid
Skokie, IL
LaPort, IN
Newark, OH
N/A
N/A
N/A
175
350
Asbestos phenolic
molding compounds
(Less than 25 percent
of sales) and
nonasbestos molding
compounds
Asbestos phenolic
molding compounds,
plasticizers, and
polyethylenes
Asbestos phenolic
molding compounds
(80 to 85 percent of
sales), nonasbestos
molding compounds,
and custom molding
items
Rogers Corporation
Manchester, CT
90-95
130-140 Asbestos phenolic
molding compounds,
nonasbestos molding
compounds, and
phenolic board
TABLE 3-28. ASBESTOS CONSUMED IN PRODUCTION OF
ASBESTOS-REINFORCED PLASTICS (METRIC TONS)23.36
1980
1979
1978
1,300
2,900
4,900
3-48
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directly into the blending stage without intermediate storage or handling.
During blending, dry asbestos, catalysts, and additions are mixed. From
this step, the mixture is formed into a resin either by heat and extrusion
or by internal shearing frictions in a Banbury mixer. The product of these
"preforming" steps is a pellet, powder, or some similar "preform," which is
either packaged and sold as an intermediate product or conveyed directly to
a type of forming process.
Forming may include a variety of processes: rolling, stamping,
pressing, or molding, depending on the product desired. Following this
process, the product is cured, thus allowing thermosetting reactions to take
place. Finally, the rough product is sent to a finishing operation, which
may involve sanding, grinding, polishing, drilling, and sawing. The degree
of finishing is dictated by the end-product use.
.Product scrap is not recovered for reuse because of the cost of
recovering the fibers once the resins have set up.14 scrap is landfilled;
baghouse waste may be recovered as filler.^
3.7.3 Emission Sources
Potential emission sources include the opening and emptying of bags of
asbestos; the emptied bags, which are not suitable to incorporate into the
mixture; the dry blending of ingredients; and resin formation. During
forming and curing, the potential for emissions, although still present, is
somewhat reduced. Other potential emission sources include finishing of the
cured products, waste disposal, housekeeping, and baghouse exhausts.
The only emission estimates available are based on engineering
estimates and cannot be considered precise. Table 3-29 contains estimates
of annual asbestos emissions from the manufacture of asbestos-reinforced
plastics.
3.7.4 Control Tecnniquests
Controls for bag opening involve use of hoods connected to exhaust
ventilation systems and baghouses. Some large manufacturers use limited
enclosure of their areas to better control exhaust air flow. 'Control
equipment in the dry blending area, resin-forming area, forming area, and
curing area includes exhaust hoods, local process exhaust equipment, and
partial enclosures to control air flow and minimize asbestos dust exposure
3-49
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TABLE 3-29. ESTIMATES OF TOTAL ANNUAL ASBESTOS EMISSIONS FROM THE
MANUFACTURE OF ASBESTOS-REINFORCED PLASTICS IN THE UNITED STATES14
Emissions
Quantity
(short tons)3
Comment
To air:
Baghouse emissions
To water:
<0.1 to -0.9
None
Free-fibers
To landfill:
Product scraps
390
Fibers coated with
polymer matrix
a Based on 1976 asbestos consumption data.
3-50
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in surrounding areas. Dust is normally exhausted to baghouses. In
finishing, hand and portable tools are normally supplied with LEVs connected
to the central ventilation/collection system. Larger stationary machines
are supplied with local exhausts near the finishing surface and, in some
cases, are supplemented with hoods over the finishing machine. Area or
machine partial enclosures are used to some extent where larger quantities
of dust are released. Housekeeping and maintenance practices include
central vacuum-clean ing systems, mobile floor sweeping/vacuum ing equipment,
and manual floor/equipment cleaning.
3.7.5 Waste Disposal
Product scrap typically is disposed of in landfills while baghouse
waste is recovered and reused in the process. Vacuum and other housekeeping
waste is bagged and disposed of in a landfill.
3.7.6 Costs
Cost information was not collected during Phase I.
3.8 ASBESTOS PAINTS, COATINGS, AND SEALANTS
Asphalt-asbestos coatings represent the major product in this industry
segment. Industrial, construction, and automotive industries use these
coatings to protect metals and tanks, to insulate pipes and tanks, and to
control sound. They have a variety of uses as undercoatings for
automobiles, flashing cements, tile cements and roof coatings but are
primarily used for the latter.37 interviews with paint manufacturers
indicate that asbestos-containing paints are no longer manufactured.38
3.8.1 Industry Statistics
Statistics on asbestos coatings, sealants, and paints that include
nunber of establishments, employment, total dollar volume, and production
are difficult to report because information available in the Census of
Manufacturers is not disaggregated sufficiently to extract specific data.
The five manufacturers of asbestos coatings and sealants are Jim Walter
Company (Celotex), Flintkote Company, GAP Corporation, Johns-Manvil le
Company, and Koppers Company, which together number 15 establishments in
this country (see Table 3-30). The Census of Manufacturers reports
statistics on 23 companies with shipments over $100,000 for SIC 29522 51,
3-51
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TABLE 3-30. MANUFACTURERS OF ASBESTOS COATINGS AND SEALANTS37
Manufactuer Plant locations
Jim Walter (Celotex) Perth Amboy, New Jersey
Chicago, Illinois
Port Clinton, Ohio
Edgewater, New Jersey
Philadelphia, Pennsylvania
Locklund, Ohio
Houston, Texas
Los Angeles, California
Birmingham, Alabama
Flintkote Company Chicago Heights, Illinois
E. Rutherford, New Jersey
GAF Corporation S. Bound Brook, New Jersey
Johns-Manville Company Manville, New Jersey
Koppers Company Youngstown, Ohio
Wickliffe, Ohio
TABLE 3-31. ASBESTOS PAINT. COATING. AND SEALANT
CONSUMPTION OF ASBESTOS1.36,42,43,44,45,46
(Short tons)
Year Quantity of asbestos consumed3
1980 10,900
1979 19,500
1978 19,100
1977 20,500
1976 19,900/36,250b
1975 31,500
1974 37,900
a Excludes asbestos consumption in roof coating production.
b The Bureau of Mines reported two widely different numbers for 1976,
3-52
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Fibrated Asphaltic Coatings, which is largely attributable to asbestos-
containing coatings.39 Because these data are not sufficiently
disaggregated, employment data for the 15 establishments using asbestos
cannot be reported. However, the best available estimate from a 1978 report
is 725 production workers in 90 of these pi ants.40
Consumption of asbestos for asbestos coatings and sealants, other than
roof coatings, radically decreased in recent years (see Table 3-31). Three
percent of asbestos consumed in this country was used to produce these
coatings.
The 20,500 short tons of asbestos consumed in 1977 produced 51 million
gallons of coatings and sealants, assuming an asbestos content of 10
percent.37 Assuming the 1977 ratio of gallons of coatings and sealants
produced to asbestos consumed remained constant, 1980 production totals 27
million gallons.
In 1978 asbestos fiber consumption for use in roof coatins was 1,150
short tons (1,050 metric tons),37 roughly 2 percent of the 63,800 short tons
(58,000 metric tons) of asbestos consumed in all roofing products.41 if the
1980 roof coating share of asbestos demand remained 2 percent of the
asbestos consumed in all asbestos roofi.ng products (29,200 short tons or
26,500 metric tons), approximately 580 short tons (530 metric tons) of
asbestos was consumed in roof coatings in 1980.
Net sales of the five producers of asbestos coatings and sealants are
given in Table 3-32, but values attributable to coatings and sealants have
not been disaggregated from total sales for all products other than coatings
sold. However, of the 23 companies evaluated, the shipment value for
fibrated asphaltic roof coatings was $60.2 mil lion.39 RTI attributed this
increase from 1972 to the lack of suitable substitutes.37
3.8.2 Process Description
Asbestos coatings and sealants usually use 10 to 12 percent asbestos.
One of the two types of coatings is made from asphalt cut back with kerosene
or mineral spirits, and the other is made with an asphalt emulsion and
water.48 Because of the variety of products and the number of producers,
these formulations are unlimited. Major components are;48
3-53
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TABLE 3-32. 1978 NET SALES FOR PRODUCERS OF
ASBESTOS COATINGS AND SEALANTS47
(Thousands of dollars)
Producer Net sales
Flintkote Company 730,175
GAF Corporation 1,063,291
Johns-Manville Company 1,648,599
Koppers Company 1,581,876
Jim Walter (Celotex) 1,672,344
3-54
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Cutback products
Cutback asphalt: 30 to 80%,
Asbestos: 10 to 15%,
Limestone and slate flour: 15 to 30%, and
Dispersant: 1%; and
Emulsion products
Emulsion asphalt: 55 to 80%,
Asbestos: 10 to 15%,
Limestone: 5 to 15%, and
Dispersant: 1%.
The following is a detailed description of the process used in preparing
coatings and seal ants.35
Asbestos pallets are moved to a staging area and weighed. The bags are
slit manually and dumped either into a hopper or directly into a fluffing
machine. This machine breaks down the compressed fibers to an open, free
condition to enable dispersion and encapsulation during asphalt mixing.
Cutting the bags and dumping the free asbestos result in fiber release.
Fiber can also become airborne or can fall to the floor, causing
house-cleaning problems and contributing to overall background level of
asbestos exposure.
Empty bags containing residual asbestos create a disposal problem in
the operation. Because several bags may be emptied at once, a waste
receiver is often made available for direct disposal. Where the bags are
laid on the floor or otherwise remain loose until fiber introduction is
completed, free asbestos creates a houskeeping problem in the work area.
Several thousand emptied asbestos bags are disposed of by a single coating
manufacturer in a year's time.
Typically, fluffed asbestos fiber is transferred to hoppers or directly
to a batch-mixing tank. Fiber transfer may be pneumatic, mechanical
(conveyors), or manual. Pneumatic transfer systems are enclosed and use
fabric filters for exhaust air; conveyors generally are enclosed. Manual
transfer may be employed for small operations or for specialized, low-volume
requirements.
3-55
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Fluffed fiber and other dry materials are brought into contact with
asphalt (and solvents, as required) in a batch tank and mixed until an even
dispersion is achieved. The batch-mixing tanks normally are enclosed-to
prevent fiber dispersion. After a short mixing time, the asbestos fiber is
bound in the asphalt. Upon completion of mixing, the asbestos is considered
completely encapsulated in the asphalt with little chance for fiber dust
exposure. When the batch is finished, the material is pumped to the
packaging (containerizing) operation.
The predominant packaging for coatings is 5 gallon pails with sealed
lids. Special orders are sometimes filled using drum containers. Bulk
shipments as in tank cars are infrequent.
3.8.3 Emission Sources
Asbestos emissions may occur during unloading and storage of
asbestos-containing bags; bag opening and dumping fibers; bag disposal;
fiber opening; manual or mechanical conveying of fluffed fibers to either
hoppers or a batch-mixing tank; and final transfer of fibers into the
slurry. Pneumatic conveyors or covered mechanical conveyors eliminate
emission sources due to transfer of asbestos fibers.
Based on observation and theoretical calculations, it is estimated that
asbestos released to the environment during manufacture of coating and paint
compounds normally will be only that entrained with air emitted from bag
filters.14 it was found that no significant scrap or water effluents are
produced and that asbestos released from bag filter emission can be
approximated at a maximum average of less than 1 ton per year for the entire
coating and paint compound production operations.14 Dust from bag filters
is the only release in which fibers are in free-fiber form. In other
effluents from washing, floor spills, and wastage of the bitumastic product,
asbestos fibers are encapsulated in the binder.
3.8.4 Control Techniques
One study revealed that hooded exhausts connected to baghouses and
exhausted enclosed conveyors are employed in fiber introduction areas of new
and large plants.35 some smaller plants did not have baghouses in 1976.^5
More recently, emissions from the bag-emptying step have been controlled by
ventilation with dust collection in baghouses;!^ this still appears to be
3-56
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BAT. Varying degrees of houskeeping are reported among different pi ants.•*$
Accordingly, inspection of some plants showed dust accumulations that may
contain fibers on all horizontal surfaces, while others regularly use vacuum
cleaning to control accumulations.35
3.8.5 Waste Disposal
Waste produced by this operation includes empty bags that had contained
pure asbestos, waste that may have occurred because of bag breaking or
spilling, and collected dust from exhausted operations. It was reported
that collected dust is recycled to the feed and no scrap material is
produced. Therefore, the emptied bags constitute the only asbestos-
containing waste materials. According to another report, several thousand
emptied asbestos bags are disposed of each year by a single coating
manufacturer.35 Emissions from empty asbestos bags are controlled by
immediately placing empty bags into containers.35
3.8.6 Costs
The 1976 cost of implementing best occupational exposure control
techniques, which also include use of baghouses, would be approximately
$1,610,000 without the cost of the industrial hygiene and medical
program.35
3.9 ASBESTOS GASKETS AND PACKINGS
3.9.1 Industry Statistics
Gaskets and packing are used to prevent fluid leakage in applications
such as valves and pump tank sealing devices. Asbestos is the most widely
used material for gaskets and packing because of its resilience, strength,
chemical inertness, and heat resistance.35
Primary manufacturers of compressed asbestos gaskets and packing,
location, and product line are presented in Table 3-33. Manufacturers of
beater-add gasketing paper use a paper-making process and are excluded from
this table. Beater-add gasketing is discussed in Subsection 3.3, Asbestos
Paper Products.
The Bureau of the Census includes asbestos gaskets and packing in SIC
3293, Gaskets, Packing, and Sealing Devices. Bureau of Census Information
3-57
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TABLE 3-33. PRIMARY MANUFACTURERS OF ASBESTOS
GASKETS AND PACKING49
Manufacturer and location
Product 1ine
Anchor Packing3
Manheim, Pennsylvania
Braiding and Packing Works
of America
Brooklyn, New York
A. W. Chesterton3
Woburn, Massachusetts
Winchester, Massachusetts
Cincinnati Gasket, Packing, and
Manufacturing Company
'Cincinnati, Ohio
Crane Packing
Morton Grove, Illinois
F. D. Farnum3
Necedah, Wisconsin
Felt Products Manufacturing
Company3
Skokie, Illinois
Garlock, Incorporated (Colt
Industries)
Charlotte, North Carolina
Asbestos packing, fiberglass
packing, rubber packing, and
gaskets
Asbestos packing, flax, and substitute
packing (including metallic, teflon,
graphite, rubber, and vegetable fiber)
Asbestos gaskets; teflon, fiberglass,
and ceramic gaskets; asbestos packing;
teflon, fiberglass, ceramic, and
extruded plastic; and graphite
packing
Asbestos gaskets, rubber and metallic
gaskets, heat shields, and
distributors for Corning glass and
Garlock packing
Asbestos packing, graphite and teflon
yarns, mechanical seals, and die-
cutters of gasketing
Asbestos gaskets, synthetic rubber
gaskets, and beater-add gasketing
Asbestos gaskets, tefl.on and steel
gaskets, asbestos sheet packing,
fibrous sheet packing, cork packing,
and chemicals
Asbestos gaskets and plastic, rubber,
and metallic gaskets
3Phasing out asbetos manufacture.
(Continued)
3-58
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TABLE 3-33. PRIMARY MANUFACTURERS OF ASBESTOS
GASKETS AND PACKING^ (Continued)
Manufacturer and location
Product 1ine
Greene, Tweed, and Company3
North Wales, Pennsylvania
Jamak, Incorporated3
Weatherford, Texas
Johns-Manville
Manville, New Jersey
Waukegan, Illinois
Lament Metal Gasket
Company, Incorporated
Houston, Texas
New Orleans, Louisiana
McCord Corporation
Wyandotte, Michigan
Nicolet
Ambler, Pennsylvania
Parker Seal
(Parker-Hannefin Corporation)
North Brunswick, New Jersey
Raybestos-Manhattan
Richardson Company
(Hercules Division)
Alden, New York
Asbestos gaskets; vegetable fiber
gaskets; and asbestos, teflon, and
nylon packing
Asbestos gaskets and rubber gaskets
Asbestos gaskets, rubber and
vegetable fiber gaskets, and asbestos
and nonasbestos packing
Asbestos gaskets and metallic gaskets
Asbestos gaskets and metallic gaskets
Asbestos gaskets, rubber gaskets,
millboard and roll board, and A/C
sheets
Asbestos gaskets and metallic and
semimetallic stainless steel gaskets
Asbestos and nonasbestos gaskets and
packing, friction materials, rivets
and related products, and other
products
Asbestos packing and teflon,
graphite, and carbon packing
aPhasing out asbestos manufacture.
(Continued)
3-59
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TABLE 3-33. PRIMARY MANUFACTURERS OF ASBESTOS
GASKETS AND PACKING^ (Continued)
Manufacturer and location
Product 1ine
Sepco
Birmingham, Alabama
Atlanta, Georgia
STANDCO Rubber and Sterling
Gasket Company
Houston, Texas
Tannetics, Incorporated
Mel rath Gasket Company
Philadelphia, Pennsylvania
Fitzgerald Gasket
Torrington, Connecticut
Utex Industries
Wiemar, Texas
Asbestos and nonasbestos gaskets and
packing
Asbestos gaskets, rubber and teflon
gaskets, and asbestos packing
Asbestos gaskets and metallic,
rubber, teflon, and stainless steel
gaskets
Asbestos gaskets and steel, cork,
cork and rubber, rubber, and metallic
gaskets
Rubber compounds, asbestos gaskets,
rubber and fiber gaskets, and
asbestos packing
a Phasing out asbestos manufacture.
3-60
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is not disaggregated sufficiently to determine employment in asbestos gasket
and packing manufacturers. However, a 1976 study35 reported 6,100
employees, while a 1978 study40 reported 1,100 workers exposed to asbestos
in the packing and gaskets industry.
Value of shipments for compressed asbestos gaskets was $58.4
million in 1977 and $24.5 million 1972.33 Asbestos gasketing cloth had a
shipment value of $7.5 million in 1977 and $2.4 million in 1972.33
Information on asbestos packings was not disaggregated sufficiently to
determine shipment values.
Asbestos consumption for packing and gaskets declined from 1978 to
1980, according to Bureau of Mines data. Table 3-34 presents asbestos
consumption figures for the period from 1978 to 1980. Grades 3, 4, 5, and 7
are used predominantly in manufacturing gaskets and packing.*
For the year 2000, the Bureau of Mines shows a low forecast for
asbestos gaskets and packing of zero metric tons, a high forecast of 30,000
•metric tons, and a probable forecast of 25,000 metric tons.2 Apparently,
consumer tastes are shifting away from asbestos-containing gasket material
and toward substitute gasketing products.49 Demand for asbestos gaskets and
packing probably will decline as demand for substitutes increases.4^
3.9.2 Process Description35
Generally, production of asbestos gaskets begins with manual opening
and dumping of bags containing asbestos into a mixing tank or a conveyor
leading to the mixer.. In some cases, compressed raw asbestos is dumped into
a fluffer for fiber opening before the mixing step. Fillers and bonding
materials also are added to the mixer and blended. Mixing may be in a dry
or wet state, according to product requirements, and multiple production
lines may be employed. The formulation from the mixer is calender-rolled
into sheeting, which may be packaged and sold to secondary manufacturers
(such as gasket cutters) for further processing. Sheeting also could be
sold to distributors serving the maintenance market.
Asbestos-based packing can be manufactured by a number of processes,
the most common being to impregnate dry yarn with lubricants that coat the
fibers. These yarns are braided into a continuous length of packing and
then are calendered to specific sizes and cross-sectional shapes. The sized
3-61
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TABLE 3-34. ASBESTOS CONSUMED IN THE PRODUCTION OF
GASKETS AND PACKING1.36
(Metric tons)
1978 31,100
1979 19,200
1980 12,300
TABLE 3-35. ESTIMATES OF TOTAL ANNUAL ASBESTOS EMISSIONS FROM THE
MANUFACTURE OF ASBESTOS GASKETS AND PACKING IN THE UNITED STATES
Emissions Quantity
to air Year (metric tons) Reference
From process 1974 13 19
From disposal 1974 13 19
From baghouses 1976 <0.09 14
3-62
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braid may be coiled, boxed, and sold to the maintenance trade, or it may be
cut and die-formed to the manufacturer's specifications. A variation of
braided packing can be produced by first extruding a mixture of asbestos
fiber, binder, and lubricants, and then braiding lubricated asbestos yarns
over extrusion.
3.9.3 Emission Sources
The primary potential emission sources are from the bag opening and
dumping of asbestos and from the mixing step. Receiving and warehousing of
raw fibers, disposal of emptied bags and product scrap, and braiding and
twisting of treated asbestos yarn also can be considered potential emissions
sources.
The only available estimates of asbestos emissions are engineering
calculations and cannot be considered precise. Table 3-35 shows such
estimates of annual release of asbestos from the manufacture of gaskets and
packing.
3.9.4 Control Techniques
Fiber release is controlled by use of hoods and LEV;34,35 dust is
typically collected by baghouses.^ Where mixing is accomplished with a
wetted compound, fiber evolution is low.34
3.9.5 Uaste Disposal
Since product scrap cannot be reused, it is disposed of in landfills.
Based on 1974 asbestos consumption data, it has been estimated that 653
metric tons (718 short tons) of asbestos is disposed of to land from the
manufacture of gaskets and packing.19
3.9.6 Costs
Information on control and operation costs was not compiled in Phase I.
3.10 ASBESTOS TEXTILES
3.10.1 Industry Statistics
Asbestos fibers may be worked into a textile form to provide an
incombustible material that retains its physical properties at high
temperatures. Asbestos textiles are manufactured in several different forms
and have various uses, including:
3-63
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Lap: used as insulation for electrical conductors;
Roving: used as insulation for heater cords, twisted to form yarn;
Yarn: woven into textiles;
Cord: used for seals, packings, and insulation;
Woth: used for curtains, blankets, and safety clothing;
Tubing: used for sleeving for electrical conductors;
Wick: used as packing and seal ings;
Tape: used for electrical insul ation.50
Four asbestos textile manufacturers are located in the United States. Their
location, employment, and product lines are presented in Table 3-36.
Total shipment value of asbestos textiles was $50.3 million in 1977 and
$37.2 million in 1972.33 Asbestos consumption by textiles for 1978 through
1980 is given in Table 3-37. Consumption by textiles for this period has been
about 1 percent or less of total asbestos consumption. From 1969 to 1974,
annual asbestos consumption for textiles ranged from 13,000 metric tons
(14,300 ,short tons) to 18,000 metric tons (19,800 short tons).2 This
apparent decline in demand for asbestos textiles is due in part to available
substitutes.51 Bureau of Mines forecasts for the year 2000 a U.S. asbestos
demand in textiles of from 0 to 10,000 metric tons (11,000 short tons),
with a probable forecast of zero tons consumed.2
3.10.2 Process Description
Asbestos textiles are manufactured from chrysotile asbestos, primarily of
the long, Group 3 fibers. The product is typically comprised of 75 to 100
percent asbestos, and organic fibers comprise 0 to 25 percent of the
product.^0 Textiles also^nay be reinforced with wire or synthetic yarns,
depending upon end use.
A majority of asbestos textile production is by conventional process,
while 5 to 10 percent of U.S. asbestos textile production is by wet
extrusion.*4 The conventional process can be subdivided into dry-woven and
damp processes, the difference being the application of moisture to the yarn
by contact with a wet roller or a mist spray. Unless noted otherwise, the
following descriptions of conventional and wet processes were adapted from
Daly.35
3-64
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TABLE 3-36. MANUFACTURERS OF ASBESTOS TEXTILES^
Manufacturer and
location
Production Total
workers employees
Product
line
Amatex Corporation'3
Meredith, NH
Norristown, PA
Johns-Manville
Manville, NJ
Raybestos-Manhattan
Marshville, NC
North Charleston, SC
Southern Textiles Company
Charlotte, NC
110
N/A
1,550
160
425
265
125
100
2,000
190
725
320
Abestos textiles and
substitute textiles
Asbestos textiles and
fiberglass textiles
Asbestos textiles,
mechanical packing,
and felt saturation
Asbestos textiles only,
asbestos textiles, and
pyroglass textiles
Asbestos textiles
fiberglass textiles
Information was taken from Reference 51 and contacts with.pi ant and
corporate personnel.
"Amatex Corporation is phasing out asbestos textile production.
TABLE 3-37. ASBESTOS CONSUMED IN TEXTILE PRODUCTION IN THE
UNITED STATES, 1978 to 1980 (Metric tons)1.2
1980
1979
1978
1,900
5,800
2,900
3-65
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In the conventional process, raw asbestos and other ingredients are
weighed and dumped into several blending machines, which operate continuously
to mix the formulation components gently. Mixing takes place as the asbestos
slowly moves toward the rear of the machine, is drawn up an incline, and
tumbles to the bottom. Part of the mix is carried over the incline and falls
into a hopper. The rear of the blending machine is enclosed and hooded to
minimize fiber evolution. As the hoppers are filled with the blended fibers,
the fibers are transferred to the carding machines or may be conveyed
pneumatically to the carding machines.
The carding operation combs the fiber mix into a parallel (oriented)
fiber mat, which is pressed mechanically and layered into a lap. At the
finishing card, the lap is separated into thin, continuous strips of fiber
known as roving. At this point, cotton, rayon, or other materials may be
added to the roving to impart strength and other characteristics. The lap,
matting, or roving may be packaged and sold to secondary industries.
Otherwise, the roving proceeds to the spinning operations.
The roving is spun and twisted a specified number of turns per inch to
give it strength. In the damp process, the roving is moistened via wet
rollers before spinning. This dampening process is employed to reduce fibrous
dust during subsequent processing. In some cases, for better product quality.
the roving is not wetted.
Spun roving, known as single yarn, can be twisted with other single yarn
or other material to produce plied yarns. Plied yarns can be coated to
produce thread or treated yarns, or woven to produce tapes, cloth, or woven
tubing. It also can be braided to produce cord, rope or braided.tubing. Spun
yarn can be processed without twisting to produce woven, braided, and
otherwise treated products.
At the weaving operations, the yarn is first put on a beam or creel,
which handles a large number of strands to feed a loom. A damp or dry loom
can be used to create cloths of different characteristics.
The wet process differs from the conventional processes in that raw
asbestos is dumped directly into a slurrying tank with water and chemicals.
The resulting slurry is extruded directly into strands. These strands proceed
to the spinning and subsequent operations similar to conventional processing.
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The wet process thus avoids the blending, and carding operations, which
generate substantial amounts of asbestos dust in the conventional process.
Wet-processed textiles possess different characteristics than do
conventionally woven products; therefore, secondary manufacturers must adapt
production techniques to compensate for altered processability and
final-product characteristics.
3.10.3 Emission Sources
Fiber release may occur during asbestos receiving and storage as a result
of damaged bags. In the conventional textile process, greatest potential for
fiber release generally is associated with bag opening and dumping (commonly
done manually), blending, transporting blended fibers, and carding. The
high-speed working of yarn in spinning, twisting, and weaving also will
release asbestos fibers. Inspection and shipping areas also may be considered
potential emission sources; however, potential is normally low at this stage
of the process.
In the wet process, potential for fiber release is greatly decreased
because blending and carding operations have been eliminated. However, bag
opening and dumping may release asbestos fibers. Spinning, twisting, weaving,
and braiding in the wet process release fewer fibers than the same operations
in the conventional process do.35
Emission data have been collected for one conventional asbestos textile
plant.11 Air was sampled as it went into the baghouse and as it was
exhausted, and samples were analyzed by optical and electron microscopy.
Results are given in Table 3-38. Engineering estimates of annual emissions to
air from U.S. asbestos textile manufacturing range from less than 0.18 metric
ton (0.20 short ton)14 to 3 metric tons (33 short tons).19 One study using
1974 asbestos consumption figures estimates that 9 metric tons (9.9 short
tons) of asbestos is emitted annually into the atmosphere as a result of
asbestos textile waste disposal.19
3.10.4 Control Techniques
Methods used for controlling fiber emissions in receiving and storage
include repairing or enclosing in plastic all damaged bags and prompt
vacuuming of spills. In fiber introduction, a semi enclosed manual
bag-opening station kept under negative pressure often is used. Blending
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CO
I
00
TABLE 3-38. TOTAL FIBER COUNTS AND FIBER REMOVAL EFFICIENCIES
FOR AN ASBESTOS TEXTILE MANUFACTURER11
Optical microscope,
500X
Plant
location
Marshville,
North Carolina
Sample
location
Upstream
Downstream
Downstream
Total
fibers
8.07 x 108
1.42 x 104
•.•»••••
Efficiency
(%)
>99.99
— — — _
Electron microscope,
16.364X
Total
fibers
2.45 x 1011
3.28 x 109
- 5.04 x 109
Efficiency
(*)
98.69
97.94
-------
machines normally are partially enclosed and under negative pressure. Blended
fiber may be loosely bagged by a bagging machine, placed in carts, and
manually pushed to the carding machines, where the bags are opened and dumped.
Another method pneumatically conveys the blended fibers from the blending
machine to a reserve hopper, which is under negative pressure, supplying the
carding machine. Carding machines are enclosed and under negative pressure.
Spinning and twisting require constant worker attention and cannot be
contained easily. Reducing spindle speeds and work practices is the major
means of controlling fiber release. Emissions from winding operations are
effectively controlled, in one instance, by enclosing and exhausting the
operation and leaving the front open for worker access.52 Clear, heavy
plastic strips suspended vertically in the opening allow operator access and
visibility while a high air velocity, low air volume system is maintained.52
Yarn wetting also is used to control emissions, and a resin may be applied to
"lock in" asbestos fibers in the woven fabric. Packaging in stretch-wrapped
plastic, shrink-wrapped plastic, and plastic bags has helped eliminate fiber
release in the shipping area.52 Dust from all capture devices and enclosures
is exhausted to baghouses, which are open-pressure and closed-suction types.
Housekeeping commonly consists of using portable and central vacuum systems.
Control methods currently in use in the textile industry appear to represent
BAT.
3.10.5 Waste Disposal
Baghouse waste may be reused, collected, and sold to other asbestos
industry segments, or bagged and placed in landfills. Emptied bags and
vacuum-cleaning waste are bagged for disposal. Waste disposal either is
contracted out or landfilled on plant-owned property.
3.10.6 Costs
Cost information was not collected during Phase I.
3.11 CHLORINE MANUFACTURING
3.11.1 Industry Statistics
Of the chlorine produced in this country, 70 percent is produced by
diaphragm cells, and an approximate total of 0.7 to 1.2 pounds of asbestos is
consumed per ton of chlorine produced.14,53 jn 1976, chlorine production was
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10 million tons;54 therefore, asbestos consumption during electrolysis was
2,500 to 4,200 tons.
Of 68 chlorine plants in the United States, 38 produce chlorine by the
diaphragm cell process. The manufacturer and location of each plant are
listed in Table 3-39.
3.11.2 Process Description
A special grade of asbestos is used as a diaphragm in the percolating
diaphragm method of chlorine production via brine electrolysis. In the
electrolytic process, cathode surfaces generally are lined with a layer of
asbestos, either in the form of paper or as vacuum-deposited fibers. The
asbestos diaphragm maintains the caustic strength and minimizes the
diffusional migration of hydroxyl ions. All diaphragms gradually clog with
residual impurities not removed from the brine and with graphite particles
that break from the anode. The diaphragms therefore are renewed at regular
intervals, on the order of 100 days or slightly longer. Depending on the
number of cells per plant, only a few cells are renewed each week; 1 plant
with 86 operating cells renewed an average of 3 cells per week.56 Asbestos
paper sheets were used extensively in diaphragm cells through the 1930s and
1940s but have been replaced, by almost all commercial diaphragm cells, with
an asbestos slurry.57
The slurry, made by mixing approximately 130 pounds of asbestos fibers
with water, is vacuum deposited through a perforated plate onto the cathode
pole. HAPP (Hooker asbestos plus polymer) diaphragms are basically the same
but contain a fl uoropolymer resin to help diaphragm bonding while reducing
voltage load. Use of paper sheets as diaphragms has diminished because the
voltage load is significantly higher for paper, as opposed to the
vacuum-deposited diaphragm. A long-fiber, high-quality paper is still being
produced and is available to customers who operate aged electrolytic
equipment, as well as the newer processes. It has been suggested that the
asbestos paper can be blended with water to form a slurry and vacuum deposited
onto the cathode, thereby eliminating potential hazard associated with
handling bags of asbestos fibers.^7
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TABLE 3-39. CHLORINE PRODUCERS WITH DIAPHRAGM CELLS55
Producer
Location
BASF Wyandotte Corporation
Brunswick Chemical Company
Champion International
Diamond Shamrock Corporation
Dow Chemical USA
E. I. duPont de Nemours and Company,
Incorporated
Fort Howard Paper Company
FMC Corporation
General Electric Company
Georgia Pacific Corporation
Hercules, Incorporated
Hooker Chemicals and Plastics Corporation
ICI Americas, Incorporated
Kaiser Aluminum and Chemical Corporation
Linden Chemicals and Plastics Corporation
01 in Corporation
Penwalt Corporation
PPG Industries, Incorporated
Shell Chemical Company
Stauffer Chemical Company of Nevada
Vulcan Materials Company
Weyerhaeuser Company
Geismer. Louisiana
Wyandotte, Michigan
Brunswick, Georgia
Canton, North Carolina
Houston, Texas
Deer Park, Texas
La Porte, Texas
:reeport City. Texas
Mttsburg, California
'laquemine, Louisiana
Midland, Michigan
Corpus Christi, Texas
Green Bay, Wisconsin
South Charleston, West Virginia
Mt. Vernon, Indiana
Plaquemine, Louisiana
Hopewell, Virginia
Niagara Falls, New York
Tacoma, Washington
Taft, Louisiana
Montague, Michigan
Baton Rouge, Louisiana
Gramercy, Louisiana
Syracuse, New York
Mclntosh, Al abama
Portland. Oregon
Tacoma, Washington
Wyandotte, Michigan
Barberton, Ohio
New Martinsville, West Virginia
Lake Charles, Louisiana
Deer Park, Texas
Henderdon, Nevada
Denver City, Texas
Wichita, Kansas
Geismer, Louisiana
Longview, Washington
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3.11.3 Emission Sources
Potential for asbestos emissions is greatest for receiving and storage,
bag opening, dumping into the mixer, cell removal, and waste disposal.
Emission data for these operations are not available.
3.11.4 Control Techniques
Emission control equipment for receiving, storage, bag opening, and
dumping is the same as in other asbestos manufacturing processes. Therefore,
work practice control for receiving and storage with procedures, such as wet
sweeping or vacuuming for spills, is the most common. For bag opening, the
control method is use of LEV and immediate containment of empty bags. One
particular plant uses a clean room kept under negative pressure in which bags
are opened.56 jne exhaust is vented through a high-efficiency particulate air
(HEPA) filter that is replaced annually. Fiber emissions from the filter were
found to be less than 0.01 fiber per field" or less than 669.5 fibers per
membrane filter. Optical microscopy was used and since volume was not
specified, a concentration could not be calculated.
Other work practices included immediate disposal of empty bags into a
metal drum and wet removal of the asbestos diaphragm. Old HEPA filters also
are placed in drums prior to disposal.
Another control measure currently available to chlorine producers is to
change from an asbestos diaphragm to a new ion-selective membrane filter.
These new membranes permit production of a higher concentrate of caustic with
lower energy consumption and are likely to be used increasingly in the
future.58
3.11.5 Waste Disposal
Disposal of empty asbestos-containing bags, fines collected by dust
collectors, and worn-out diaphragms is in accordance with EPA and Occupational
Safety and Health Administration (OSHA) regulations. One of the chlorine
producers seals metal drums containing emptied bags and filters and contracts
for solid waste disposal.56 Wash water containing spent asbestos from the
diaphragms is mixed with the wastewater of a nearby company, which treats and
disposes of the waste.
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3.12 ASBESTOS INSULATION
Asbestos may be an ingredient in materials used for thermal insulation,
acoustical insulation, and fireproofing. Asbestos-containing products used as
insulation include asbestos millboard and rollboard, asbestos commercial
papers, asbestos cements, asbestos blankets, asbestos coatings and sealants,
and sprayed asbestos insulation. Asbestos products that perform the function
of thermal insulation include asbestos millboard and rollboard, asbestos
commercial papers, asbestos cements, and asbestos blankets.59 Asbestos
millboard, rollboard, and commercial papers, which are paper products, are
discussed in Subsection 3.3 and will not be discussed further here.
Insulating cements were used where insulation that could be troweled was
required. Similar to asbestos-containing joint cements and patching
compounds, these products have been replaced on the market with asbestos-free
products, such as calcium silicate or diatomite.59 Asbestos blankets are
manufactured by the asbestos textiles industry, which is discussed in
Subsection 3.10, and are not considered further here. Asphalt and tar-based
coatings and sealants to which asbestos is added may be considered to have
insulating properties. For example, asbestos-containing automobile
undercoatings have acoustical insulating properties and insulate against
corrosion. Asbestos coatings and sealants also may be applied to structural
steel for fire-proofing.37 Asbestos coatings and sealants are discussed in
Subsection 3.8.
3.13 SHOTGUN SHELLS
3.13.1 Industry Statistics
Asbestos may be used to manufacture base wads for shotgun shells.
Currently, only one plant, Remington Arms Company in Bridgeport, Connecticut,
manufactures asbestos-containing shotgun shell wads and only about 5 percent
of its shells contain asbestos. This small amount was to be eliminated during
1981.60 Remington Arms Company in Lonoke, Arkansas, also fabricates shotgun
shells using the asbestos-containing wad made in Connecticut. In 1974,
Remington used approximately 454 metric tons (500 short tons) of asbestos to
manufacture shotgun shells.6* Given the availability of substitutes for
asbestos wads, disappearance of this market is imminent.60
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3.13.2 Process Description
Asbestos is mixed with wood flour and wax and pressed into base wads.2
The mixture's formulation, by weight, is:61
Asbestos: 36 percent,
Wood flour: 54 percent, and
Wax: 10 percent.
3.13.3 Emission Sources
Emission sources likely in the manufacture of asbestos-containing shotgun
shells include receiving and warehousing of asbestos, opening and dumping of
asbestos, mixing, wad pressing, and subsequent handling and processing.
Baghouse operations, including exhausts, are sources of fiber release
into the environment.62 Based on high baghouse efficiency, emissions from
baghouse exhausts are very small.62
3.13.4 Control Techniques
Dust from emission points is exhausted to particulate control devices.
In 1974, these included mechanical collectors and spray scrubbers.61 In a
1978 report, the authors, in estimating emissions, indicate that Remington has
employed a baghouse to control emissions.62 The switch to substitutes
ultimately will eliminate asbestos emissions from its facility.
3.13.5 Waste Disposal
Asbestos-containing waste from shotgun shell manufacturing is minor.
Baghouse collections are recyclable and product scrap wastes are minor.3
3.13.6 Costs
Cost information was not collected during Phase I.
3.14 ASPHALT CONCRETE
3.14.1 Industry Statistics
Asbestos is added to asphalt to give it greater strength and longer life
and is used as a thin topping layer on some airport roadways, bridges, and
street curbing.61 As of 1974, an estimated 5,000 asphalt concrete plants were
located in the United States, about 50 of which used asbestos each year, and
4,100 metric tons (4,500 short tons) of asbestos were used.61 By 1978,
asbestos use in asphalt concrete was less than 91 metric tons (100 short tons)
per year as a result of environmental restrictions and concerns over health
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effects and Government regulations,64 most likely EPA and OSHA regulations.
Current asbestos use in asphalt concrete is negligible and its continued use
is unlikely.63 The National Asphalt Pavement Association was not aware of any
asphalt concrete plant that uses asbestos.6^
3.14.2 Process Description
In the manufacturing process, bags of asbestos are opened manually and
dumped into a conveyor system or are introduced opened into the mixer. The
asbestos is mixed first with dried aggregate, after which hot liquid asphalt
is added to the asbestos-containing aggregate and thoroughly mixed.6!
3.14.3 Emission Sources
Emissions can occur during manual bag opening, emptying of asbestos into
the conveyor hopper, and dry mixing. Empty bags, if not incorporated into the
mixture or properly contained, can be points of fiber release. Considering
only negligible amounts of asbestos currently are used, emissions are probably
small. Once bound into the asphalt concrete product, asbestos emissions are
not considered significant.61
3.14.4 Control Techniques
The common method of introducing fiber into the process consists of
dumping the unopened plastic bags of asbestos directly into the mixer.61 This
procedure alleviates emission problems associated with manual opening and
dumping and conveying loose fibers. No information was found on current use
of collection devices by asbestos-asphalt plants. In 1974, it was thought
that most of these plants would install small fabric filtering devices and a
few would install venturi scrubbers to control asbestos emissions.61
3.14.5 Waste Disposal
Considering the small quantities of asbestos probably used in asphalt
concrete, the amount of asbestos containing waste probably is also small. In
product scraps asbestos fibers are encapsulated by the asphalt mixture and
cannot become airborne.64
3.14.6 Costs
During Phase I, no cost information was collected for asphalt concrete
production.
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3.15 FABRICATING
3.15.1 Industry Statistics
Fabricators, or secondary processors, refer to firms that purchase
products from primary manufacturers and either fabricate these materials
(e.g., cutting and drilling of cement sheets) or process them together with
other materials for incorporation into an end product (e.g., use of reinforced
plastics in electrical generators). Field fabrication is discussed in Chapter
4 as part of construction. It is not always possible to isolate a secondary
industry in a strict sense because primary producers often purchase from each
other. For example, manufacturers of friction materials may purchase from
asbestos textile manufacturers. Furthermore, primary producers often perform
operations to their own products that could be considered secondary processing
or fabricating. For example, a producer of asbestos flooring felt may also
apply the polyvinyl chloride coating and print or emboss a pattern in the
coating.
The secondary industries can be defined by the primary segment of the
asbestos manufacturing industry that services them, as follows:-^
A/C products;
Asbestos friction materials;
V/A floor tile;
Asbestos-reinforced plastics;
Asbestos paper products;
Asbestos paints, coatings, and sealants;
Asbestos gaskets, seals, and packing materials; and
Asbestos textiles.
Each of these secondary industry segments will be described here briefly.
Unless noted otherwise, information on secondary industries is from a 1978
OSHA study.66
3.15.1.1 A/C Products. The secondary market for A/C pipe is limited.
Most of the product is manufactured and finished for direct end use in the
construction industry. A/C sheets have both construction and industrial
application. Cement shingles are used in residential construction areas,
while corrugated sheets are usually precut and fabricated at the primary
plants for various construction activities. The cooling tower industry is a
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major end user of flat A/C sheets usually fabricated at the primary industries
on a special-order basis. Industrial applications for A/C sheets include
table tops for schools and laboratories, hoods and vents for corrosive
chemicals, small appliance components, electrical switchboard components, and
other uses where the strength and heat-chemical-resistant nature of asbestos
cement is required. Most of these applications are serviced by small cement
board fabricators located throughout the country who do job shop work for
specific orders. Approximately 50 such firms are located throughout the
country, typically employing 20 to 25 persons per plant. Additional users of
A/C sheets, such as furniture manufacturers and large electrical firms,
fabricate sheets for their own use.
Based on sales data from primary industries, it is estimated that
approximately 25 percent of the A/C sheets go through the secondary
fabricators.
3.15.1.2 Asbestos Friction Materials. Secondary fabricators of friction
material products are primarily in the automotive aftermarket with additional
markets in some industrial applications.
The automotive aftermarket consists of three sectors:
Firms that rebuild or reface friction components for brakes,
clutches, and transmissions;
Firms that repackage friction materials; and
General service and brake repair.
Approximately 1,150 firms are associated with refacing and rebuilding friction
materials. For the most part, these are small, one-plant operations; however,
some larger corporations also have such plants (i.e., Bendix). The major
distinction between these operations and similar operations in the primary
segments manufacturing friction materials is that because these plants do not
handle raw asbestos fiber, their asbestos control problems are somewhat
different.
Compared to the other sectors, the repacking sector is small with an
estimated 100 small operations throughout the United States.
The general service and brake repair sector of the automotive after-
market is very large and involves a number of subsectors. Estimated
establishments involved are as follows:
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Repair shops 110,000
Dealerships 32,900
Tire/battery/accessories 29,200
Department store repair shops 5,800
Service stations 190,000
Total 367,900
3.15.1.3 V/A Tile. V/A floor tile is manufactured by the primary
industries and is cut and shipped directly to either the construction industry
or the end user. There is no secondary fabricator for this product.
3.15.1.4 Asbestos-Reinforced Plastics. Primary industry segments
manufacture molding compounds, mainly phenolic molding compounds, and sell
this granulated material to a myriad of secondary molding fabricators. Major
segments of this secondary industry include appliances such as household
appliances, utensils, and tools; various automobile applications in the
ignition, transmission, and wiring system; the wiring device industry;
electrical switch gear manufacturers; makers of closures such as bottle and
jar caps; and the communications and electronics industry. It is extremely
difficult to determine the entire scope of the secondary market for asbestos-
reinforced plastics. Industry estimates some 3,000 secondary fabricators of
reinforced plastics and perhaps 5,000 separate product end users. However,
the percentage of these plastic fabricators that use asbestos-reinforced
plastics or other materials cannot be determined. Some of the primary
industries fabricate their own plastic products, but, for the most part,
asbestos-reinforced plastics go through secondary processes.
Based on the sales percentage of the primary industry to secondary
fabricators, it is estimated that approximately 70 percent of asbestos-
reinforced plastics go through secondary fabricators. An estimated 5,700
people are employed in the secondary processing of asbestos-reinforced
plastics.67
3.15.1.5 Asbestos Paper Products. Asbestos paper is used in areas such
as roofing, gaskets (commonly called beater-add gaskets), thermal and
electrical insulation material, and underlaying for sheet flooring. Many
primary manufacturers of asbestos paper also fabricate and finish the product
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for sale to the end user. Specifically, manufacturers of asbestos roofing
felt have their own saturating plants, which in turn sell the roofing product
directly to the construction industry. Individual establishments acting as
secondary fabricators of asbestos roofing products are minimal. A significant
portion of asbestos paper goes directly into the secondary fabricators for
gasketing material. Other paper is sold to manufacturers of cooling towers
where the paper is saturated, cut, and .fabricated as a sandwich filler for
some applications.
Based on sales data from primary manufacturers, an estimated 60 percent
of asbestos paper goes through some form of secondary fabrication before
reaching the construction industry or other end users. An estimated 6,300
people are employed in secondary fabrication of asbestos paper products.67
3.15.1.6 Asbestos Paints, Coatings, and Sealants. These products
manufactured by the primary industries have no secondary fabricator market.
Their end-use applications involve the construction industry, home remodeling
markets, and automotive undercoatings.
3.15.1.7 Asbestos Gaskets, Seals, and Packing Materials. During these
secondary fabricating steps, packing of gasket materials may be impregnated
with polymers, latex, or other chemicals to impart certain properties to the
material. These secondary fabricators cut, slit, or punch the material to
specific shapes for end users. Where strength and pressure sensitivity is not
critical, gasket cutters use asbestos paper from the paper segment of the
primary asbestos industry. Finally, asbestos yarns made by primary asbestos
textile mills are sold to secondary fabricators to be used as packing material
for pumps and other applications that require this high-strength material. In
some instances, primary textile operations will manufacture their own packing
material and sell it directly to end-user industries.
Based on sales data from primary industries, approximately 95 percent of
packing and gasket material are estimated to go through secondary fabricating
firms. An estimated 6,300 people are employed in this segment.67
3.15.1.8 Asbestos Textiles. The wide range of asbestos textiles has a
correspondingly wide range of secondary markets. Asbestos cloth is used in
welding curtains and screens, safety garments, protective clothing, and
reinforced plastic laminates. Asbestos yarn is used as filler in the wire
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and cable industry, as the main ingredient in braided packings, and is woven
in the process of making certain types of felts.
With some large textile companies, fabricating certain products may occur
within the primary textile industries. However, for the most part, asbestos
textiles go through secondary fabricating steps prior to end use. For this
reason and based on sales data, it is estimated that approximately 90 percent
of the asbestos textiles manufactured by the primary segment go through
secondary processing. An estimated 3,200 people are employed by secondary
processors of textiles.6?
3.15.2 Process Description
In general, operations involved in secondary fabrication are similar to
finishing operations of the primary manufacturing segments. They may use such
operations as grinding, sawing, sanding, punching, pressing, or slitting,
depending on the fabricated product desired.
3.15.3 Emission Sources
Secondary fabricators receive their asbestos products from the primary
industry in a bound form and do not have the problem of handling raw asbestos
fibers.40 Some asbestos-containing dust may be released during the receiving
of these products due to residual dust on the product or through breakage or
abrasion during transport.40 Because occupational exposures from these
sources are probably not serious, emissions to the atmosphere are probably
insignificant. The important emission sources include actual fabrication
operations, such as grinding, drilling, sanding, sawing, routing, cutting,
slitting, and others that destroy the integrity of the product.40
3.15.4 Control Techniques
Basically, secondary industry segments use the same type of control
equipment and work practices as the primary industry segments to reduce
employee exposure to asbestos dust. Control equipment and work practices used
include central vacuum systems for floor and equipment cleaning; down-draft
tables, local exhausts on hand tools, and area hoods on large machines
connected to a central ventilation system with air filtering through a
baghouse,40 which represents BAT for dust collection; wet grinding and sawing
where product integrity is not affected adversely; cleaning of raw materials
and products to minimize dust exposure in handling and packaging; proper
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handling of scrap materials; and routine equipment and floor cleaning.™ In
addition,, some primary manufacturers try to minimize fiber emissions in
secondary industries by coating or waxing their products.
3.15.5 Waste Disposal
Waste from secondary processors will resemble that from finishing
operations among primary manufacturers. Secondary processors, however, do not
have the capabilities to recyle product scrap or vacuum system and baghouse
waste. It is likely that they use landfills for waste disposal.
3.15.6 Costs
No attempts were made to obtain current cost information on fabricating
operations and control systems.
3.16 REFERENCES
1. Bureau of Mines, U.S. Department of the Interior. Asbestos in 1980,
Annual Advance Summary. In: Mineral Industry Surveys. Washington, D.C.
May 15, 1981. 7 p.
2. Clifton, R. A. Asbestos Mineral Facts and Problems, 1980 Edition.
Bureau of Mines, U.S. Department of the Interior. Washington, D.C.
Bulletin 671. 1980. 17 p.
3. Kendall, D. L., et al. Economic Impact Analysis of Controls on Certain
Use and Exposure Categories of Asbestos (draft). Research Triangle
Institute. (Prepared for Office of Toxic Substances, U.S. Environmental
Protection Agency. Research Triangle Park, North Carolina.) November
1980.
4. 1980 Review: The Asbestos Mining Industry—United States. Asbestos.
62(7):11-12. January 1981.
5. International Industry Review—1979. Part II: The Asbestos Mining
Industry—United States. Asbestos. 6l_(6):l7-lB. December 1979.
6. W. E. Davis and Associates. National Inventory of Sources and Emissions,
Cadmium, Nickel, and Asbestos, 1968. (Prepared for National Air
Pollution Control Administration. Washington, D.C.) February 1970.
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7. Harwood, C. T. Asbestos Air Pollution Control. Illinois Institute of
Technology Research Institute. IIEQ Document No. 71-8. (Prepared for
the Illinois Institute for Environmental Quality. Chicago, Illinois.)
November 1971.
8. Fowler, D. P. Derivation of Emissions Estimates shown in Figure
(Unpublished). SRI Internationil. Menlo Park, California. 28 p.
9. Harwood, C. F., and T. P. Blaszak. Characterization and Control of
Asbestos Emissions from Open Sources. Illinois Institue of Technology
Research Institute. (Prepared for National Environmental Research
Center, U.S. Environmental Protection Agency. Research Triangle Park,
North Carolina.) EPA-650/2-74-090. September 1974. 203 p.
10. Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency. Control Techniques for Asbestos Air Pollutants.
Research Triangle Park, North Carolina. Publication AP-117. February
1973. p. 3-4.
11. Harwood, C. F., P. Siebert, and T. P- Blaszak. Assessment of Particle
Control Technology for Enclosed Asbestos Sources. Illinois Institute of
Technology Research Institute. EPA-650/2-74-088 (Prepared for Office of
Research and Development, U.S. Environmental Protection Agency. Research
Triangle Park, North Carolina.) October 1974. 126 p.
12. Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency. Background Information on National Emission Standards
for Hazardous Air Pollutants, Proposed Amendments to Standards for
Asbestos and Mercury. Research Triangle Park, North Carolina.
EPA-450/2-74-009. October 1974. p. 59-72.
13. Little, A. D. Characterization of the U.S. Asbestos Papers Markets.
(Prepared for Sores, Inc.) May 1976. p. 42.
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14. Meylan, William M., et al. Chemical Market Input/Output Analysis of
Selected Chemical Substances to Assess Sources of Environmental
Contamination: Task III. Asbestos. Syracuse Research Corporation.
(Prepared for the Office of Toxic Substances, U.S. Environmental
Protection Agency. Washington, D.C.). August 1978. 323 p.
15. Bureau of the Census, U.S. Department of Commerce. 1977 Census of
Manufactures. Preliminary Report. Asbestos Products. Standard
-Industrial Classification 3292. Washington, D.C. May 1979. p. 8.
16. Johns-Manville. Friction Materials. Chrysotile Asbestos Fiber Technical
Bulletin. Denver, Colorado. AF-112A. Undated. 1 p.
17. Gregg, R. T. Development Document for Effluent Limitation Guidelines and
New Source Performance Standards for the Textile, Friction Materials, and
Sealing Devices Segment of the Asbestos Manufacturing Point Source
Category. Effluent Guidelines Division, U.S. Environmental Protection
Agency. Washington, D.C. EPA-440/-174/035-a. December 1974. 91 p.
18. Margolin, S. V., and B. U. N. Igwe. Economic Analysis of Effluent
Guidelines: The Textiles, Friction, and Sealing Materials Segment of the
Asbestos Manufacturing Industry. Arthur D. Little, Inc.
EPA-230/2-74/030. (Prepared for Office of Planning and Evaluation, U.S.
Environmental Protection Agency. Washington, D.C.) July 1975. 61 p.
19. SRI International. Asbestos: An Information Resource. R. J. Levine
(ed.) (NIH) 79-168. (Prepared for the National Cancer Institute,
National Institute of Health. Bethesda, Maryland.) May 1978.
20. Laney, M. Trip Report—Initial Plant Visit, Bendix Corporation, May 14,
1981. Research Triangle Institute. Research Triangle Park, North
Carolina. May 21, 1981 5 p.
21. Reference 3, p. 135-152.
22. RTI contacts with personnel for the Johns-Manville Corporation. 1981.
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23. Reference 3, p. 287-305.
24. Clifton, R. A. Asbestos. Mineral Commodity Profiles. Bureau of Mines,
U.S. Department of the Interior. Washington, D.C. September 1977.
17 p.
25. Carton, R. J. Development Document for Effluent Limitations Guidelines
and New Source Performance Standards for the Building, Construction, and
Paper Segment of the Asbestos Manufacturing Point Source Category.
Washington, D.C. Office of Air and Water Programs, U.S. Environmental
Protection Agency. EPA-440/l-74-017-a. February 1974. 143 p.
26. Harwood, C. F., and P- K. Ase. Field Testing of Emission Controls for
Asbestos Manufacturing Wast Piles. EPA 600/2-77-098. IIT Research
Institute. (Prepared for Office of Research and Development, U.S.
Environmental Protection Agency. Cincinnati, Ohio.) May 1977. 135 p.
27. Reference 14, p. 107-143.
28. Boltin, J., J. Helsen, and A. Deruytteri. Nature, Structure, and
Properties of Asbestos Cement Dust. British Journal of Industrial
Medicine. -_27_: 33-41. 1980.
29. Rajhans, Gason S., and Gordon M. Bragg. Engineering Aspects of Asbestos
Dust Control. Ann Arbor Science, 1978. p. 32-35.
30. Ontario Ministry of the Environment. Asbestos as a Hazardous Contaiminat
II. January 1975.
31. Siebert, P. C., T. C. Ripley, and C. F. Harwood. Assessment of Particle
Control Technology for Enclosed Asbestos Sources—Phase II. Illinois
Institute of Technology Research Institute. (Prepared for Office of
Research and Development, U.S. Environmental Protection Agency. Research
Triangle Park, North Carolina.) EPA-600/2-76-065. March 1976. 134 p.
32. Johns-Manville Corporation. Vinyl Asbestos Floor Tile. Chrysotile
Asbestos Fiber Technical Bulletin. AF-114A. Denver, Colardo. Undated.
1 p.
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33. Bureau of the Census, U.S. Department of Commerce. Abrasive, Asbestos,
and Miscellaneous Nonmetallic Mineral Products. Industry Services. 1977
Census of Manufacturers. MC77-1-32E. July 1980. p. 32E-24.
34. Wright, M. D., et al. Asbestos Dust. Technological Feasibility and
Economic Impact Analysis of the Proposed Federal Occupational Standard.
Part I. Research Triangle Institute. (Prepared for the Occupational
Safety and Health Administration, U.S. Department of Labor. Washington,
D.C.) September 1978.
35. Daly, A. R. Technological Feasibility and Economic Impact of OSHA
Proposed Revision to the Asbestos Standard. Roy F. Weston Environmental
Consultants-Designers. (Prepared for Asbestos Information
Association/North America. Washington, D.C.) March 29, 1976. 189 p.
36. Clifton, R. A. Asbestos. 1978-1979 Bureau of Mines Minerals Yearbook.
Washington, D.C. Bureau of Mines, U.S. Department of the Interior.
1980. 14 p.
37. Reference 3, p. 171-180.
38. Reference 3, p. 316.
39. Bureau of the Census, U.S. Department of Commerce. Industry Series,
Petroleum and Coal Product. 1977 Census of Manufacturers. Publication
No. MC77-1-29A. July 1980.
40. Research Triangle Institute. Asbestos Dust. Technological Feasibility
Assessment and Economic Impact Anlaysis of the Proposed Federal
Occupational Standard. Part III. (Prepared for the Occupational Safety
and Health Administration, U.S. Department of Labor. Washington, D.C.).
September 1978.
41. Clifton, R. A. Asbestos. Mineral Commodity Profiles. Bureau of Mines,
U.S. Department of the Interior. Washington, D.C. July 1979. 19 p.
42. Clifton, R. A. Asbestos. 1974 Bureau of Mines Minerals Yearbook.
Bureau of Mines, U.S. Department of the Interior. Washington, D.C.
11 p.
3-85
-------
43. Clifton, R. A. Asbestos. 1975 Bureau of Mines Minerals Yearbook.
Bureau of Mines, U.S. Department of the Interior. Washington, D.C.
12 p.
44.. Clifton, R. A. Asbestos. 1976 Bureau of Mines Minerals Yearbook.
Bureau of Mines, U.S. Department of the Interior. Washington, D.C.
11 p.
45. Clifton, R. A. Commodity Data Summaries, 1977- Bureau of Mines, U.S.
Department of the Interior. Washington, D.C. January 1977. p. 12.
46. Clifton, R. A. Mineral Commodity Summaries, 1978. Bureau of Mines, U.S.
Department of the Interior. Washington, D.C. January 1978. p. 12.
47. Moody1s Investors Service, Inc. Moody1s Industrial Manual, New York.
1979.
48. Johns-Manville Corporation. Asphalt Coatings. Chrysotile Asbestos Fiber
Technical Bulletin. Denver, Colorado. Undated. 1 p.
49. Reference 3, p. 180-192.
50. Johns-Manville Corporation. Asbestos Textiles. Chrysotile Asbestos
Fiber Technical Bulletin. AF-111A. Denver, Colorado. Undated. 1 p.
51. Reference 3, p. 192-202.
52. Lewinsohn, H. C., C. A. Kennedy, J. E. Day, and P. H. Cooper. Dust
Control in a Conventional Asbestos Textile Factor. Annals of the New
York Academy of Sciences. I. J. Selikoff and E. C. Hammond (eds.).
330:225-241. 1979.
53. Reference 3, p. 97.
54. Bureau of the Census, U.S. Department of Commerce. Inorganic Chemicals.
In: Current Industrial Reports. Washington, D.C. Publication No.
M28A(77)-4. April 1977.
55. Chlorine Institute, Inc. North American Chior-Alkali Industry Plants and
Production Data Book. Pamphlet 10. January 1980. 17 p.
3-86
-------
56. Conrad, L. Trip Report—Intital Plant Visit, LCP Chemicals-New York,
Inc. Research Triangle Institute. Research Triangle Park, North
Carolina. March 5, 1981.
57. Meyland, W. M., et al. U.S. Asbestos Paper Industry and Substitutes for
Asbestos Paper and Asbestos Brake Linings. Syracuse Research
Corporation. (Prepared for the Office of Toxic Substances, U.S.
Environmental Protection Agency, Washington, D.C.) September 1979.
58. Cell Developers Work to Cut Electric Bills. Chemical Week. June 10,
1981. p. 51.
59. Reference 3. p. 329-33.
60. Reference 3, p. 345.
61. Reference 12, 140 p.
62. Reference 14, p. 276-178.
63. Reference 13, p. 346-351.
64. Reference 14, p. 275-276.
65. Telecon. Laney, M., Research Triangle Institute, with Garker, B.,
National Asphalt Pavement Association. August 13, 1981. Use of asbestos
/
in asphalt concrete.
66. Reference 35, p. 11-21 to 11-25.
67. Lee, B. S., et al. Asbestos Dust. Technological Feasibility Assessment
and Economic Impact Analysis of the Proposed Federal Occupational
Standard. Part II: Economic Appendix, Asbestos Dust in Construction.
Research Triangle Institute. (Prepared for the U.S. Department of Labor,
Occupational Safety and Health Administation, Washington, D.C.)
September 1978.
3-87
-------
4. INDUSTRY DESCRIPTION: DEMOLITION, RENOVATION, AND CONSTRUCTION
4.1 INDUSTRY DESCRIPTION: CONSTRUCTION
Approximately 75 to 80 percent of all asbestos manufactures are used by
the construction industry. The industry's complexity and flexibility make it
difficult to follow consumption of asbestos products although the literature
describes installation and application processes. The industry consumes
asbestos/cement (A/C) products, flooring products, roofing materials, paper
products, insulation, and coatings and sealant materials. Asbestos products
have'specific uses and markets but may be shared by several construction
industry factions, such as single-family dwelling contractors, multiunit
residential dwelling contractors, or nonresidential building contractors.
Because asbestos products are widely used in a variety of construction jobs, a
construction industry profile will provide the necessary basic information to
review accurately the scope of the asbestos emission standard. Of particular
interest are portions of the industry involved in demolition and renovation
operations as covered by the standard. Therefore, this section addresses
construction separately from renovation and demolition.
4.1.1. Industry Statistics
In 1977, 1.2 million establishments were operating as general building
contractors and operative builders (SIC 15), heavy construction contractors
(SIC 16), special trade contractors (SIC 17), and subdividers and developers
(SIC 6552).! Of the 1.2 million establishments, 70 percent were special trade
contractors, 24 percent were general builders, 5 percent were involved in
heavy construction, and 1 percent was subdividers and developers.
Business receipts for construction projects totaled $244.8 million, a
49-percent increase over receipts collected and reported in 1972.1 The 1977
employment figures showed a total of over 4 million construction workers in
the United States, similar to the number reported in 1972.
4-1
-------
Assuming little change in 1977 statistics, the largest industry segment
is made up of nonpayroll establishments. However, the 720,000 establishments
in this category only accounted for 8 percent of business receipts. These
businesses are controlled by 735,000 self-employed proprietors and working
partners who contract their own services. Seventy-seven percent of these
establishments are primarily special trade contractors.
Establishments with payroll employees numbered 450,000 in 1977, employing
approximately 4.3 million persons and retaining 279,000 proprietors and
working partners. This smaller industry segment accounted for 92 percent of
total business receipts. Only 18 percent of payroll establishments employed
more than 10 workers but accounted for 76 percent of all business receipts
received in the industry. Table 4-1 summarizes 1977 and 1972 statistics for
construction establishments with and without payroll.
Business receipts were over $10 billion for payroll establishments
located in New York, Illinois, Texas, and California. The largest dollar
income for construction was in California with $25 billion in receipts, and
the lowest was in Vermont with $380 million in receipts. On the average, 86
percent of business receipts were paid for construction work by home State
establishments.
General building contractors and operative builders are involved in
residential and nonresident!"al construction that includes dwellings, stores,
farm buildings, and office buildings. General contractors perform services
either under contract with the project owner or under the operative builder
who undertakes projects to be sold. Heavy construction general contractors
are involved in highway and street construction; bridge, tunnel, and elevated
highway construction; water, sewer, and utility projects; dams and water
projects; air fields; heavy industrial facilities; and other heavy
construction that involves either earth moving or erecting constructions and
appurtenances other than buildings.
Special trade contractors are involved in specialized activities such as
plumbing, heating, and air conditioning; painting, paper hanging, and
decorating; electrical work; masonry and other stonework; plastering, drywall,
and insulation; terrazzo, tile, marble, and mosaic work; carpentry; roofing
and sheet metal work; concrete work; water well drilling; structural steel
4-2
-------
TABLE 4-1. SUMMARY STATISTICS FOR ESTABLISHMENTS WITH AND WITHOUT PAYROLL: 1977 AND 19721
All establishments
Industry
Construction industries and
subdividers and developers
' Construction industries
co
General building contractors
and operative builders
Heavy construction general
contractors
Special trade contractors
Plumbing, heating, and air
conditioning
Electrical work
Subdividers and developers.
not elsewhere classified
Number
1,200,407
1,183.221
286,320
55,210
841.691
106,603
75,958
17,186
Proprie-
tors and
working
partners
1.013,961
996,942
219,077
37,449
740,416
79,806
58,230
17,019
All
employees
4,272,659
4,233,658
1,180,747
917,083
2,135,828
458,687
356,591
39,001
All
business
receipts
x 1,000
244,815,905
239.426.850
98,116.714
51,674.514
89,635,622
22,650,620
15,213,602
5,389.058
Establ isliuents without payroll
Number
720.393
708,285
130,349
23.915
554,021
50,168
39.194
12.108
Proprie-
tors and
working
partners
734,652
719,381
130,596
24,366
564 419
51,108
39,656
15.271
All
business
receipts
x 1,000
20,150,970
17,804.427
8,330.156
946,739
8,527,532
1,219,435
731,760
2.346,543
Number
480,014
474,936
155,971
31.295
287,670
56,435
36,764
5,078
Establishments with payroll
Proprie-
tors and
working
partners
279,309
277.561
88,481
13,083
175.997
28,698
18,574
1,748
All
employees
4,2/2,659
4,233,658
1,180.747
917,083
2,135,828
458,687
356,591
39,001
Al 1
bus inuss
receipts
x 1,000
224.664,938
221.622.423
89,786.558
50,727. 7/5
81.108,090
21.431.185
14,481,842
3,042,515
(Continued)
-------
TABLE 4-1. SUMMARY STATISTICS FOR ESTABLISHMENTS WITH AND WITHOUT PAYROLL: 1977 AND 1972 (Continued)
All establishments
Industry
1972
Construction industries and
subdividers and developers
_p» Construction industries
General building contractors
and operative builders
Heavy construction general
contractors
Special trade contractors
Plumbing, heating, and air
conditioning
Electrical work
Subdividers and developers.
Number
920,806
906,134
208.383
42.717
653.325
88.371
57.816
14,672
Proprie-
tors and
working
partners
748,253
743,855
149,579
27,823
564,737
65.528
42.952
4.398
All
employees
4,145.779
4,083,465
1,149.520
827.346
2.106.599
456,100
323,748
62,314
All
business
receipts
x 1,000
164.457,691
161,091,002
67.374.118
31,921,251
61,774,631
16,394,924
10,126.111
3.366.689
Establishments without payroll
Number
482.865
476,107
75,329
14,726
384,343
25,070
25.361
6.758
Proprie-
tors and
working
partners
473,819
471,354
M.663
14,383
383,592
34.782
25.224
2.465
All
business
receipts
> 1.000
8,607,039
8,369,423
3,024,195
460,355
4,863.871
779,456
518,076
238,616
Number
437.941
430.027
133.054
27.991
268.982
53,301
32.455
7,914
Establishments with payroll
Proprie-
tors and
work 1 ng
partners
274.43''
272.501
77.916
13,440
181,145
30.746
17,728
1.933
Al 1
enipl oyees
4, 14 '.1.7/9
4.083,465
1.149.520
827,346
2.106,599
456,100
323,748
62,314
Al 1
bus mess
receipts
t 1,000
155,849,652
152,721,579
64,459,923
31,460,896
56,910,760
15,615,468
9,608,035
3,128,073
not elsewhere classified
-------
erection; glass and glazing work; excavating and foundation work; and wrecking
and demolition. Special trade contractors may work for general contractors
under subcontract or directly for the project owner. Subdividers and
developers are primarily engaged in subdividing real property into lots and in
developing it for resale for their own account or for others.
General statistics for payroll establishments by various construction
industries are provided in Table 4-2. Regardless of types of construction
work and business, certain fundamental characteristics are shared among
various industry classes. Some of these characteristics can be summarized to
define the industry further:
Construction work is performed at temporary locations that vary in
size, physical boundaries, and working surfaces;
Construction work is usually performed in open air, subject to
weather variability;
Construction work varies as the project progresses from initiation
to completion, demanding a variety of materials, equipment, and
skills;
Type and duration of emissions are variable due to the significant
influence wind and atmospheric conditions can have on dust
dispersal;
Portable tools and equipment are preferred on temporary locations
and for field work, making local exhaust ventilation (LEV) and dust
collection a major engineering problem; and
Employment is transient in construction, permitting tradesmen and
laborers to work for several different contractors at several
different sites per year.
4.1.2. Renovation
Under Section 61.21 of the asbestos emission standard, renovation has
been defined as "the removing or stripping of friable asbestos materials used
on any pipe, duct, boiler, tank, reactor, turbine, furnace, or structural
member." Wrecking or removal of load-supporting structural members is
excluded. Therefore, removal of insulation materials containing asbestos and
removal of sprayed-on asbestos-containing materials for remodeling, repair, or
renovation (operations as described by the construction industry) could come
under the standard's purview. However, as the standard stipulates, only
removal or stripping of friable asbestos materials amounting to that covering
more than 80 meters of pipe or that covering more than 15 square meters of a
duct, boiler, tank, reactor, turbine, furnace, or structural member is
regulated. The Administrator excluded from the scope and application of the
standard all residential buildings except private multiunit dwellings with
more than four units.
4-5
-------
TABLE 4-2. GENERAL STATISTICS FOR ESTABLISHMENTS WITH PAYROLL BY INDUSTRY: 1977
CTl
SIC
Code
15,16
17
15
1521
1522
1531
154
1541
1542
16
1611
162
1622
1623
1629
Employees Payroll
Total
Number of Construction All Construction construction
Industry establishments All workers employees workers receipts
Construction Industries and
subdlviders and developers
Construction Industries:
General building contractors
and operative builders:
General contractors,
residential buildings:
Single- family houses
Other residential buildings
Operative builders
General contractors,
nonresidential buildings:
Industrial buildings and
warehouses
Nonresidential buildings, not
elsewhere classified
Heavy construction general contractors:
Highway and street construction
Heavy construction, except highway:
Bridge, tunnel, and elevated
highway construction
Water, sewer, and utility lines
Heavy construction, not elsewhere
classified
480,014 4,272.659 3,565,469 54,960,063 43,112,399 214,844,319
100,993 437,681 382,806 3,736,421 3,066,031 21.292,675
4,775 55,589 45,707 646,375 484,890 4,442,110
23,477 173,819 109,702 2,026,118 1,053,389 19,812,272
8,259 202,070 170,787 2.852,817 2,247,193 12,855,514
18,467 311,588 254,360 4,274,933 3,189,805 27.137,768
11,748 ' 267,917 232,810 3,595,809 2.927.185 15.021,207
979 38,093 33,187 535,877 438,750 2.247,284
10,227 198,354 173,093 2,837,270 2,347,495 9.361,092
8,342 412,719 318,375 7,298,267 5,274,120 21.624,035
(Continued)
-------
TABLE 4-2. GENERAL STATISTICS FOR ESTABLISHMENTS WITH PAYROLL BY INDUSTRY: 1977 (Continued)
Employees
SIC
Code
17
1711
1721
1731
174
1741
1742
1743
175
1751
1752
1761
1771
1781
179
1791
1793
1794
1795
1796
1799
Number of Construction
Industry establishments All workers
Special trade contractors:
Plumbing, heating, and air
conditioning
Painting, paper handling, and
decorating
Electrical work
Masonry, plastering, and tile
setting:
Masonry, stone setting, and other
stonework
Plastering, drywall, and insulation
work
Terrazzo, tile, marble, and mosaic
work
Carpentering and flooring:
Carpentering
Floor laying and other floorwork
Roofing and sheet metal work
Concrete work
Water well drilling
Miscellaneous special trade
contractors:
Structural steel erection
Glass and glazing work
Excavating and foundation work
Wrecking and demolition work
Installing building equipment,
not elsewhere classified
Special trade contractors, not
elsewhere classified
56,435
27.369
36,764
24,815
16.745
3,891
24,388
8,969
20,577
16,974
4,305
2,592
3.283
16,521
978
2,442
20.626
458,687
133,106
356,591
152,167
180,326
22,324
124,646
40,990
171,931
118,116
22.352
47,166
26,125
104.092
8.295
40,474
128.440
368,993
121.288
296,946
142,797
158,479
19,084
114,673
33,724
146,307
107,085
18,720
40,911
19.335
91,552
6,998
32,630
107,632
Payroll
All
employees
6,413,961
1,361,463
5,482,519
1.493,214
2.261,906
255,475
1,202,203
453,107
1.967,824
1,209,879
237,036
673,768
316,974
1,207,669
89,020
752,439
1,383,720
Construction
workers
5.024,679
1,191,130
4,496,695
1,350,307
1,900,704
207,643
1,060,685
352,246
1.555,286
1,042.622
188,307
556.462
228,741
1,020,923
70.233
601,593
1,085,630
Total
construction
receipts
21.072,098
3.171,129
14,221,277
3,775,368
6,057,467
766,114
3,597,222
1,616,932
6,200,390
4,097,293
1,090,418
1,803,310
1,006,566
4,215,722
240,630
1899,047
4,407,208
6552
Subdividers and developers, not
elsewhere classified
5.078
39,001
17.518
414,002
414,002
1,053,473
-------
Portions of the construction industry that would engage in "renovating
operation" are general contractors of residential but not single-family
buildings; general contractors of nonresidential buildings that include
industrial buildings and warehouses; and general contractors who engage in new
construction, addition, alteration, remodeling, and repair of commercial,
institutional, religious, amusement, and recreational buildings. In addition,
the following special trade contractors would most likely engage in
renovation:
Plumbing, heating (except electric), and air conditioning;
Electrical work;
Plastering, drywall, acoustical, and insulation work;
Roofing and sheet metal work;
Wrecking and demolition;
Installation or erection of building'equipment, not elsewhere
classified (includes contractors who dismantle industrial
equipment); and
Special trades, not elsewhere classified (includes insulation of
pipes and boilers and dismantling of forms of poured concrete).
Table 4-2 provides general statistics on establishments, employment, and
business receipts for those construction types. Information taken from the
Census of Construction Industries also includes business receipts for
maintenance and repair- Assuming all renovation would be classified as such,
this information may provide a dollar volume guide relative to all
construction receipts per construction type. Table 4-3 provides maintenance
and repair receipt data for all building contractors other than single-family
dwellings reported in the 1977 Census of Construction Industries.
Table 4-4 provides maintenance and repair receipt data for industrial
structures, facilities, and installations reported under "nonbuilding
construction." Nonbuilding construction is the Census classification that
includes power plants; sewage treatment and water treatment plants; and blast
furnaces, petroleum refineries, and chemical complexes. Although the standard
does not specifically cite plants and complexes, they may be construed as
industrial facilities and installations for this review. Assuming maintenance
and repair of nonbuilding construction would be solely by special trade
contractors, receipts reported for general contractors and operative builders
are not included in the table. Also, receipts attributed to repair and
4-8
-------
TABLE 4-3. MAINTENANCE AND REPAIR RECEIPT DATA FOR BUILDINGS OTHER
THAN SINGLE-FAMILY DWELLINGS
Industry series
Maintenance and
repair receipts
($l,OOOs)
Percent of
all receipts
General contractors
Residential buildings other
than single-family3
Industrial buildings and
warehouses3
Nonresidentialj other than
industrial buildings and
warehouses3
Operative builders
All buildings other than
single-family
Special trades
Plumbing, heating, and air
conditioning
219,692
1,255,011
1,237,968
90,358
2,810,744
5.0
10.0
4.6
0.5
13.3
Electrical work
Plastering, drywall ,
acoustical , and
insulation
Roofing and sheet metal work
2,112,087
534,807
1,413,893
14.9
8.8
22.8
aDoes not include receipts from outside the particular SIC.
4-9
-------
TABLE 4-4. MAINTENANCE AND REPAIR RECEIPT DATA FOR NONBUILDING CONSTRUCTION
Industry series
acoustical, and
insulation
Roofing and sheet metal work
Maintenance and
repair receipts
($l,OOOs)
41,601
Percent of
all receipts
Plumbing, heating, and air
conditioning
Electrical work
PI astering, drywall ,
375,207
439,976
115,341
1.8
3.1
2.0
0.7
4-10
-------
maintenance of streets, highways, or other heavy construction have been
subtracted from totals reported in the Census.
Standard Industrial Classification (SIC) codes of "Installation or
Erection Building Equipment," not elsewhere classified, include dismantling of
machinery and other industrial equipment contractors and installation
contractors that may be involved in renovating operations as defined by the
standard. The 1977 Census reports 2,442 payroll establishments, an employment
of 40.5 thousand workers, and business receipts of $1.95 billion. Total
construction receipts were $1.9 billion. New construction, which may also
include renovation under this SIC code, and maintenance and repair receipts
were over $900 million.
The special trade contractors, not elsewhere classified, includes
contractors engaged in waterproofing, damproofing, and fireproofing that may
require renovating as defined by the standard. However, because several
special trade types are included in this particular classification and because
the Census does not provide specific information, it is impossible to
determine the percentage of the $4.4 billion in receipts that can be
attributed to renovating operations.
4.1.3 Demolition
In 1979 under a "New Directions Grant" from the Occupational Safety and
Health Administration (OSHA), a demolition industry profile was prepared.2
The profile showed that 2,300 companies in the United States are involved in
demolition as opposed to the 836 reported in 1972 and the 978 reported in the
1977 Census of Construction Industries. The researchers used a variety of
sources but found over 1,600 firms advertising demolition services in
telephone directories of 157 cities. Extrapolation revealed approximately
2,300 firms capable of demolition work.
Primary data showed that most of the demolition firms—approximately 68
percent—provide a full range of industrial, commercial, and residential
structure demolition. The remainder are involved in specialized jobs, such as
chemical plants, port facilities, or utilities equipment. The report
characterized demolition work by the short-term jobs and substantial
subcontracting.2
The survey showed that the average firm employs 12 permanent and 10
temporary workers and that the average duration of demolition projects is 3.87
4-11
-------
32
J£
30
28
26
24
22
20
18
i 16
LU
a
K 14
u.
12
10
8
6
4
2
0
•
__
s
5? SS
«M PM
CM f«J
un un
tn
* §
CM
S? S5
-------
ft
22
20
18
16
14
CJ
a
e
"• 10
8
6
4
2
0
x"
^__
—
&
in
en
«
in
3?
CO
*? ;
U9
55 S ^
-------
20
18
16
14
a
UJ
cc
12
10
8
s?
LC9
vp t vp ! vj> ^^""^^"""T™1^™"™™"^ ?
eN I tf"* I 3*- I I I*
° I ° I ° I I ,
10 15 20 25 30 35 40 45
NUMBER OF AVERAGE TEMPORARY EMPLOYEES
Figure 4-3. Average temporary employee distribution.
50
< I-
70
4-14
-------
380
360
340
320
£ 300
1 280
Ul
t-
\ 260
i
e
£ 240
u.
o
* 220
CO
£2 200
Ul
O
180
Ul
5 160
IT
o
Ul
tr
LU
C9
-------
days for a residence, 9.56 for a commercial structure, and 14.7 for an
industrial facility- However, it did not report specifically the duration of
demolitions involving asbestos removal. Figures 4-1, 4-2, 4-3, and 4-4 were
taken from the report that shows distribution of demolition work, distribution
of permanent and temporary employees as a function of the frequency of
contracting work, and comparison of the two types of employees.
According to previous EPA estimates, fewer than 3,000 demolitions per
year are covered by the standard.3 For verification, EPA regional National
Emissions Standards for Hazardous Air Pollutants (NESHAPs) officers indicated
that an estimated 2,618 demolition projects covered by the standard are
completed in a year.4 Further investigation revealed that contracts were
awarded for demolition of 2,596 buildings in 1978.4 These figures, however,
were not qualified because the number of demolition contracts involved
asbestos. In addition, it was found that EPA's Region V received notices of
79 demolition and renovation projects in 1978 and that 731.4 demolition
contracts were awarded Region V contractors. This could mean that of the 731
contracts, only 79 were covered by the standard; that all 731 involved
asbestos but only 79 were done within Region V; or that the remaining
contracts were neither initiated nor reported.
Table 4-5 summarizes the data TRC reported on 1978 demolition projects.
4.2 PROCESS DESCRIPTIONS
4.2.1. Introduction
The construction industry consumes approximately 75 to 80 percent of all
asbestos products. Except for A/C sheet, flooring felts, and textiles shared
by secondary industries, these products, designated in Table 4-6, are sold
directly to construction contractors either by the manufacturers or through
distributors. Products are used in the following construction types:
Private single-unit residences,
Private multiunit residences and nonhousekeeping units,
Residential additions and alterations,
Private nonresidential buildings,
Educational and religious facilities,
Hospitals and institutions,
Farm nonresidential buildings,
Telephone and telegraph facilities,
4-16
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TABLE 4-5. SUMMARY OF DEMOLITION DATA^
Number of
contractors
Region I
Connecticut
Maine
Massachusetts
New Hampshire
Rhode Island
Vermont
Region II
New Jersey
New York
Region III
Del aware
District of Columbia
Mary! and
Pennsylvania
Virginia
West Virginia
Region IV
Alabama
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
Region V
Illinois
Indiana
Michigan
Minnesota
Ohio
Wisconsin
148
36
13
70
10
17
2
316
107
209
249
8
11
38
130
41
21
251
16
95
28
26
4
45
17
20
524
185
75
83
24
87
70
Number of
contracts
674
144
16
457
8
39
10
150
78
72
577
47
72
10
445
3
0
119
15
16
56
12
3
13
3
1
731
12
58
209
9
125
318
Percent of Percent of
total total
contracts contractors
26.0 6.5
5.8 13.8
22.2 10.8
4.6 10.9
28.2 22.8
(Continued)
4-17
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TABLE 4-5. SUMMARY OF DEMOLITION DATA (Continued)4
Region VI
Arkansas
Louisiana
New Mexico
Oklahoma
Texas
Region VII
Iowa
Kansas
Missouri
Nebraska
Region VIII
Colorado
Montana
North Dakota
South Dakota
Utah
Wyoming
Region IX
Arizona
California
Hawaii
Nevada
Region X
Alaska
Idaho
Oregon
Washington
Number of
contractors
181
13
27
10
35
96
130
54
22
36
18
106
50
7
10
4
25
10
304
27
245
12
20
92
2
11
31
48
Number of
contracts
121
27
36
0
28
30
141
29
0
44
68
16
0
4
2
6
1
3
22
2
19
0
1
45
12
7
6
20
Percent of Percent of
total total
contracts contractors
4.7 7.9
5.4 5.7
0.6 4.6
0.9 13.2
1.7 4.0
4-18
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TABLE 4-6. ASBESTOS PRODUCTS CONSUMED BY THE CONSTRUCTION INDUSTRY5
Products
Secondary
market
Final
product
consumption
A/C pipe
A/C sheet
A/C siding/shingles
Vinyl/asbestos (V/A) floor
tile
Flooring felts
Roofing felts
Pipe insulation
Electrical insulation
Mi 11 board
Coatings/seal ants
25% to
fabricators
60% flooring
manufacturers
Textiles (thermal/electrical
insulation)
90% wire and
cable industries;
braided rocking
and felt manu-
facturers; elec-
trical and
thermal
insulation users
Heavy construction
Building construction
manufacturing and
furniture
Building construction
Building and special
trade construction
Building and special
trade construction
Building and special
trade construction
Building and special
trade construction
Building and special
trade construction
Building and special
trade construction;
steel and glass
industries
Building; heavy and
special trade
construction; auto-
motive and home
repair
10% directly to
building; heavy
special trade
construction
and
4-19
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Water facil Hies,
Sewer works,
Electric and other public utilities,
Public housing, and
Miscellaneous public construction including military facilities.
Usage of asbestos products involves the activities shown in Table 4-7.
In addition to erection and installation activities, maintenance and
repair activities may require removal of asbestos products. Demolition
activities may also involve removal or destruction of asbestos-containing
materials.
Construction contractors recently have been called upon to encapsulate
sprayed-on asbestos materials in lieu of removing friable asbestos materials
from public buildings. Although this activity neither uses nor removes
asbestos materials, it involves potential asbestos emissions. The number and
types of contractors called on to perform this activity are not known,
partially because measures to correct asbes.tos fiber fallout in public
buildings are just being addressed by Federal and State Governments.
The process or operational descriptions for each of the above activities
are presented in one of the following sections: . construction, renovation,
and demol Hi on.
4.2.2 Construction
4.2.2.1 A/C Pipe Installation. Although pipes are manufactured in
standard sizes and in half and quarter lengths with proper couplings, pipes
occasionally must be cut to length and machined to fit couplings. Pipes that
are machined all over by the manufacturer do not require additional machining.
Either special tools designed for cutting and machining pipe or a standard
power saw equipped with an abrasive or diamond wheel is used.
An economic analysis of the occupational standard revealed that 1976
production was 90 million linear feet of pipe, that the installation
production rate was 223 feet per day for a typical crew of three or four
people, and that one 15-minute cutting machining operation is required for
approximately 1,300 feet of pipe. It was estimated that 9,230 cuts per year
would be made in the field on A/C pipe.^
4.2.2.2 A/C Sheet Installation. Field cutting of A/C sheets may be
required at corners and around wall apertures. Holes must be drilled on A/C
4-20
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TABLE 4-7- DISTRIBUTION OF ACTIVITIES AMONG DIFFERENT CONSTRUCTION TYPES&
Type
Activities
1.
2.
Private single-unit residences
Private multiunit residences
and nonhousekeeping units
3.
Residential additions and
alterations
4.
Private nonresidential
buildings; industrial and
commercial offices; and
miscellaneous construction
5.
Educational and religious
facilities
Drywal1 removal
A/C sheet installation
A/C architectural panel
installation
Installation of built-up roofing
and replacement roofing
Roof removal
Drywal1 removal
Thermal, acoustical, and
decorative material
and removal
maintenance
A/C sheet installation
A/C architectural panel
installation
Installation of built-up roofing
and replacement roofing
Roof removal
Drywal1 removal
Thermal, acoustical. "and
decorative material
and removal
maintenance
A/C sheet installation
A/C architectural panel
installation
Installation of built-up roofing
and replacement roofing
Roof removal
Drywal1 removal
Thermal, acoustical, and
decorative material maintenance
and removal
A/C sheet installation
A/C architectural panel
installation
Installation of built-up roofing
and replacement roofing
Roof removal
Drywal 1 removal
Thermal, acoustical, and
decorative material maintenance
and removal
(Continued)
4-21
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TABLE 4-7- DISTRIBUTION OF ACTIVITIES AMONG DIFFERENT
CONSTRUCTION TYPES (Continued)6
Type
Activities
6. Hospitals and institutions
7. Farm, nonresidential
8. Telephone and telegraph
facilities
9. Water facilities
10. Sewer works
11. Electric and other public
utilities
12. Public housing
A/C sheet installation
A/C architectural panel
installation
Installation of built-up roofing
and replacement roofing
Roof removal
Drywall removal
Thermal, acoustical, and
decorative material maintenance
and removal
Drywall removal
Thermal, acoustical, and
decorative material maintenance
and removal
Thermal, acoustical, and
decorative material
and removal
maintenance
A/C pipe installation
Thermal, and acoustical insulation
maintenance and removal
A/C pipe installation
Thermal and acoustical insulation
maintenance and removal
Electric insulation installation
maintenance and removal
A/C sheet installation
A/C architectural panel
installation
Drywall removal
Installation of built-up roofing
and replacement roofing
Roof removal
(Continued)
4-22
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TABLE 4-7- DISTRIBUTION OF ACTIVITIES AMONG DIFFERENT
CONSTRUCTION TYPES (Continued)6
Type
Activities
13. Miscellaneous public
construction including
military facilities
14. Demolition
A/C sheet installation
A/C architectural panel
installation
Drywall removal
Installation of built-up roofing
and replacement roofing
Roof removal
Removal of thermal, acoustical,
and decorative material
4-23
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sheets for attachment purposes. Circular saws equipped with either an
abrasive wheel or a diamond- or carbide-tipped blade are used for cutting, and
standard portable drills are used for the holes. The same economic analysis
showed that of the 96 million square feet of A/C sheet produced in 1976, 75
percent is consumed by the construction industries. It was estimated that
field fabrication is required on 5 to 30 percent of the installed sheet and
that each sheet averages 32 square feet. Therefore, of approximately 2
million sheets consumed by construction, only 100,000 to 600,000 sheets
require field cutting per year.
The average amount of A/C sheet used per project was reported as 24,750
square feet. The 1976 production figure for A/C sheet was used to determine
that 2,909 projects using A/C sheet were undertaken that year. If, for each
site, field fabrication is required on 5 to 30 percent of the sheets,
approximately 38 to 230 sheets need field finishing.
4.2.2.3 A/C Architectural Panel Installation. Most A/C panels are
ordered to specifications from the manufacturer, minimizing the need for field
fabrication. However, since the panels are attached to frames with screws,
drilling is necessary. Standard electric drills are used for this purpose.
Occasionally, cutting is required, which is performed by using a portable
circular saw equipped with an abrasive or diamond cutting wheel.
The 1976 figures showed that 3 million square feet of A/C panel was
produced and that the daily installation rate is approximately 495 square feet
for an average crew of four people.^ Economic analysis of the occupational
standard showed that approximately 8,365 square feet of panel is needed per
project and that 350 projects used A/C panels in 1976. Analysis also showed
that for every 12,000 square feet, approximately 32 cuts taking 15 minutes
each were required and that approximately 6,500 holes had to be drilled.
Therefore, for each site 22 cuts and 4,500 holes are necessary (assuming a
constant market demand).
4.2.2.4 Installation of Asbestos Roofing Felts. The economic analysis
of the occupational standard indicated that asbestos felts coated with asphalt
are cut with a knife or shears at the installation site. Then, the felts are
placed over the roof deck in layers and roofing tar is mopped on between the
layers.8 in another economic analysis, it was reported that three plies are
4-24
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layered for built-up roofing.9 Two types of roofing installations have been
described.10 One type of built-up roofing is applied by layering uncoated
asbestos roofing felts, and the second involves layering previously coated
felts and using cold adhesives to cement the plies together. In addition to
built-up roofing, asbestos felts are often used as an underlayment for other
roofing materials such as asphalt shingles.
Approximately 200 square miles of commercial built-up roofing is
installed annually and the daily installation rate of a crew size of seven is
about 2,400 square feet.8 The number of cuts and the timing required for each
depend upon the size of the roof and the desired size of each ply.
The quantity of annually installed roofing reported in 1976 by the
National Roofing Contractors Association may have changed radically, as
indicated by current production numbers.5 The 1979 production of roofing
felts was 138,500 short tons.9 Since roofing felts usually are manufactured
in weights of 9 1/2 to 15 pounds per 100 square feet,10 based on an average,
the felt installed in built-up roofs could not have exceeded 66 square miles.
Since roofing felts are not used solely for built-up roofing, the amount may
still be less.
4.2.2.5 Roof Removal.. Approximately 100 square miles of commercial and
industrial roofing is repaired or renovated annually requiring removal of
roofing felts containing asbestos.. With a crew of 5 people, the average daily
removal rate is 16 squares or 1,600 square feet of old roofing.8 Ninety-nine
percent of removal is manual, in which roofing is pulled from the deck. When
insulation is attached, the roofing is usually cut into 2- by 2-foot
squares, which are thrown manually to the ground.11
4.2.2.6 Drywall Removal. Asbestos associated with drywall removal is
contained in spackling, taping, and joint compounds. Although use of
asbestos-containing patching and joint compounds was banned in 1977, prior
construction used such compounds.
Therefore, it is likely that of 1.65 billion square feet of drywall
removed each year, some—the footage installed prior to 1977—may produce
free-form asbestos fiber emissions when removed.7 Drywall usually is pulled
from the frame manually; however, tools such as axes or hammers may be
required initially to break into the wall in some circumstances.12 The wall
4^25
-------
joints are cut and, if the drywall had been nail-applied to wood studs, the
nails are punched through in order to salvage the material. If the drywall
had been screw-applied onto metal, the screws are removed and the joint tape
is cut.
4.2.2.7 Sanding Asbestos Floor Tile. A common practice among floor tile
installers was sanding old floor tile with conventional belt sanders before
resurfacing. However, in their instruction manuals, manufacturers warn
against sanding old tile, a practice most contractors have discontinued. The
number of installations where sanding is continued is not known.
4.2.2.8 Installation of Asbestos Cloth and Rope Lagging Electrical
jnsulation. Applying asbestos textile insulation materials such as cloth and
rope lagging usually is used for electrical insulation and requires pulling
the cloth or rope from rolls or coils and cutting to desired lengths. The
cloth and rope are usually cut with mechanical cutters, knives, clickers,
dies, or scissors. Cloth can be torn from the roll, but this is not
recommended. Materials are fitted, hammered and nailed, glued, and sewn
during application.
4.2.2.9 Installation of Thermal Insulation. Thermal insulation usually
consists of paper and millboard, but cloth or woven tape may be used.
Installing paper and millboard sheets for thermal insulation requires field
fabrication to fit the materials onto equipment and structures. Paper and
millboard sheets must be cut to shape and length. For piping, flues, and
circular stacks, paper, millboard, cloth, or tape is wrapped around the
objects in layers and can be fixed to the surface with wire, bands, or
sheathing. Fabric covering can also be applied with or without coating or
paints. For furnaces, boilers, turbines, reactors, kettles, or other heated
vessels, the asbestos millboard is attached to the surfaces by studs, bolts,
bands, expanded mesh, or sheet metal.?
4.2.2.10 Removal of Nonfriable Insulation Materials. Like drywall,
asbestos blanket (cloth), rope, and asbestos paper and millboard insulation on
turbines, boilers, pipes and ducts is manually torn off surfaces or from
cavities. Approximately every 3 to 5 years large amounts of insulation are
removed as a result of inspections and repairs required on turbines in
electric power-generating plants.7
4-26
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4.2.3 Renovation
4.2.3.1 Removal of Friable Insulation and Fireproofing Materials.
Removal of A/C insulation spray-applied prior to 1973; removal of friable,
molded thermal and acoustical insulation containing asbestos and of powdered
A/C insulation manually wet-applied prior to 1975; and removal of any other
sprayed-on materials containing more than 1 percent asbestos applied before
1977 are regulated by the EPA emission standard for asbestos. Therefore, in
addition to dislodging material from ceilings, walls, pipes, ducts, or other
surfaces with scrapers, picks, drills, saws, or other hand-held or powered
tools, removal will include containment of the area, sufficiently wetting the
asbestos material prior to stripping, or capturing emissions at the source by
LEV.
Sprayed-on asbestos materials were commonly used by the construction
industry from 1946 to 1973.13 In 1950 more than half of all multistory
buildings constructed in the United States used some form of sprayed-on
fireproofing, and in 1968 40,000 tons of fireproofing was sprayed on in U.S.
buildings.^ in 1970 40,000 tons of fireproof ing was used again for the same
purpose.15 A 1971 product bulletin stated that by 1971, more than 50,000,000
square feet of structural steel had been fireproofed with a particular brand
of thermal insulation.^ These sprayed-on materials containing asbestos were
used for fireproofing, thermal and acoustical insulation, decoration, and
condensation control. Fireproofing accounted for the largest amounts on
structural steel components of multistory buildings. Thermal insulation was
applied on turbines and in reaction vessels in chemical plants and refineries,
boiler breechings, and stacks. Sprayed-on materials containing asbestos were
applied for decorative ceilings and for noise absorption in large public
buildings and restaurants. Walls and ceilings of indoor swimming pools,
laundries, textile plants, and other industrial buildings where condensation
might have caused corrosive damage were sprayed with asbestos-containing
materials.15 EPA has estimated that approximately 8,600 public schools
contain friable asbestos materials.
4.2.3.2 Encapsulating With Sealants. Encapsulating with sealants has
replaced removal of sprayed asbestos materials from buildings. Nearly any
sealant or encapsulation method will reduce asbestos fallout contamination.
Sealing of sprayed asbestos surfaces involves applying material that will
4-27
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envelop or coat the fiber matrix and eliminate fallout and protect against
contact damage. Sealants are applied over the surface of the material using
airless spray equipment at low-pressure settings.
4.2.4 Demolition
To demolish buildings specified under EPA's emission standard,
contractors must proceed as directed by the standard. The process includes
removing friable asbestos materials prior to wrecking, wetting materials prior
to removal, removing members coated with friable asbestos, and subsequent
wetting when friable materials are stripped from these units. Fixtures such
as lights, partitions, and other mounted objects must be removed before
removal of friable materials containing asbestos: insulation, fireproofing,
acoustical insulation, and decorative coatings containing asbestos. Actual
removal of material requires spraying area with water or amended water,
scraping, drilling or cutting, placing the material into drums or doubly
lined plastic bags, and disposal. Demolition proceeds with cleanup of debris
by placing it, too, in drums or doubly lined bags for disposal. Once these
procedures are completed wrecking can commence.
According to the Background Information Document (BID) for the 1973
asbestos emission standard, 4,000 apartment buildings and 22,000 commercial or
industrial buildings are demolished annually.16 However, based upon reports
to the Agency, EPA estimated that, in 1 year, less than 3,000 demolitions are
covered by the standard. In a study of demolitions it was found that in 1978,
2,596 demolition projects subject to the standard were initiated, which agreed
with the EPA estimate.4
4.3 EMISSION SOURCES AND EMISSIONS
In the construction industry emission sources are as variable as are
asbestos products. Asbestos products are basic building materials that, when
combined with other materials to form a complete support system, have a finite
service life. They have specific applications within the support system.
Therefore, emission sources are identified by the operations employed for
certain activities such as product installation, maintenance and repair,
renovations, and demolition of support systems built with these materials.
Process descriptions contained in the previous section identified
emission sources. For installation of building materials, emission sources
4-28
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are generally prefabrication; installation or application; cleanup of waste
materials; and disposal of waste materials and dust collected from local
exhaust systems. For removal of emission source operations, include removal
of any objects attached to asbestos-containing building materials, initial
break or cut into materials, ripping of material from its frame, waste
cleanup, and disposal of waste materials and dust from local exhaust and
vacuum systems. Table 4-8, taken from the economic analysis of the proposed
occupational standard, lists some operations and available, related emission
data for various products.? Most published emission data describe the
occupational environment and were obtained with sampling and analysis
procedures that may or may not be appropriate for determining ambient asbestos
fiber concentrations. However, data are presented only to demonstrate sources
of asbestos emissions.
4.4 CONTROL TECHNIQUES
The temporary nature of construction projects, sporadic use of asbestos
materials, extensive use of portable tools, and effect of weather on outdoor
projects make it difficult to control asbestos emissions from construction
activities.^ Published literature and reports have described the various
techniques that, when applied, lower occupational exposures and simultaneously
control environmental emissions. However, control of occupational exposures
in construction relies heavily on work practices; e.g., using slow-running
tools, vacuuming fallen waste from machining, using dust suppressants for
cleanup, and cutting one piece at a time.
Most operations involving asbestos products in construction are
fabricating, except for removal and demolition. The Asbestos Information
Association (AIA) has recommended that for controlling emissions from
fabrication operations, low-volume, high-velocity controls for cutting A/C
sheets should be used, high-efficiency vacuum cleaners should be used if
available, and good work practices should be followed at all times.
Installation, removal, demolition, and renovation control techniques are
addressed separately in the following paragraphs.
4.4.1 A/C Pipe Installation
Although little field fabrication of pipe is necessary due to the type
of product available, LEV systems for portable tools have been developed by
Johns-Manville;^ however, the extent to which they are being used is unknown.
4-29
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TABLE 4-8. EMISSION SOURCES AND OCCUPATIONAL EXPOSURES7
Operation
Activity
Occupational exposures
(f/cm3)
Machining A/C pipe
Machining A/C sheet
Sawing
Drilling
Machining A/C panels
Laying roofing felts
Tearing off roofing
felts
Drywal1 removal
Sanding floor tiles
Tearing out electrical
turbine insulation
(blankets)
Installation
Installation
Installation
Installation
Repair
Repair
Installation
Maintenance
Tearing old insulation Renovation
Renovation
Removal of ceil ing
sprayed with
A/C mix
Dry removal
Wet (water)
Wet (amended water)
0.0-0.5—controlled
Greater than 25 (C)a--uncontrolled
2 to greater than 24(C)a
Less than 5—uncontrolled
Greater than 20—uncontrolled
Less than 2—controlled
Less than 2 except for overhead
drilling--uncontrol 1 ed
2 to greater than 25(C)a
0.1-0.2 (8-h TWA)
0.0-1.7 (8-h TWA)
15 (8-h TWA)
1.2
0.1-5.9 (8-h TWA)
• 0.2-26.3
82.2
23.1
8.1
a(C) represents a ceiling concentration.
(Continued)
4-30
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TABLE 4-8. EMISSION SOURCES AND OCCUPATIONAL EXPOSURES (Continued):
Operation
Activity
Occupational exposures
(f/cm3)
Cleanup debris Renovation
containing asbestos
Wetted (water)
Wetted (amended
water)
Cleanup scrap Renovation
insulation
containing asbestos
Removal of insulation Demolition
0.3-4.0
0.2-0.3
Less than 0.1 to 3.7
Greater than 80(C)a
a(C) represents a ceiling concentration.
4-31
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Work practices have been recommended that include, cutting with carbide blade
equipment; using snap cutters; using .manual and powered lathes designed for
pipe; cutting holes with specially designed hole cutters; drilling holes with
a drill and rasp or a chisel and rasp; and using specially designed equipment
for tapping.7 in addition, recommendations have been made against blowing
out dust and cuttings with compressed air or using power-driven saws for dry
cutting or leveling pipe.l? A second control method is a change in the
process in which field machining would be eliminated by special orders of
prefabricated pipe. A third control .method is elimination of A/C pipe usage.
PVC (polyvinyl chloride) pipe is already a commonly used alternative.5 Work
practices emphasizing cleanup of debris and catching of chips produced by
cutting and machining would prevent reentrainment into the air by other
activities. AIA recommends that equipment surfaces be free of dust
accumulations.1? These work practice guides are a result of field studies to
establish the best available techology (BAT) in controlling asbestos emissions
from field fabrication operations.
4.4.2 A/C Sheet Installation
Portable powered drills and saws (circular and sabre) equipped with
dust collection hoods have been developed and tested. AIA recommends hand
saws equipped with carbide blades for infrequent cutting to limit generation
of airborne fibers.18 Clippers designed with slow cutting speeds also
generate coarse particles and few airborne fibers. These tools are
commercially available, but the extent of their use is unknown. Other
practices include placing a vacuum box behind the sheet to collect particles
falling from behind cutting and drilling actions and a piece of plywood behind
the sheet during drilling to prevent emissions from underneath.19 Wet cutting
is another possible control technique that has been used to control
occupational exposures to asbestos in A/C product manufacturing plants.
Whether or not such a technique has been field tested or used at all by
construction contractors is unknown.19
To a large extent, sheets and panels are prefabricated, minimizing the
need to cut and drill holes. Manufacturers often receive orders with
specifications for precutting. Special fabricating shops that work with A/C
4-32
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product distributors provide prefabrication services,^ but prefabrication
may not be possible in all installations, especially when allowances must be
made for ducts, conduits, and other protrusions.
As with A/C pipe, use of nonasbestos-containing substitutes is another
control method. Market demand for A/C sheet has been affected directly by
substitutes, and sales volume has decreased approximately 5 percent annually
since 1977.20
Work practices—such as wet sweeping, vacuuming, collecting debris from
machining, and keeping equipment dust free—help minimize airborne asbestos
fibers. These control methods provide field fabricators with the best means
of controlling asbestos emissions under special conditions of field work.18
4.4.3 Drywall Removal
Occupational exposure to asbestos has been described for the removal of
drywall for either repair or demolition activities.21 However, engineering
controls for occupational exposures have not been described for pulling
drywall from building frames. Work practices that involve wetting may reduce
emissions, but current studies on asbestos emission controls have not
indicated that spraying drywall joints with water or amended water is
applicable as it is for insulation removal. However, containment as described
for removal of sprayed-on asbestos materials may be possible for areas where
drywall is to be repaired or removed.^ Good housekeeping practices, such as
wet sweeping, vacuuming, and keeping equipment dust free are recognized
controls for occupational exposure that minimize airborne asbestos fibers.
4.4.4 Installation and Removal of Roofing Felts
Engineering controls for occupational exposures to asbestos from
cutting and applying plies or pulling off roofing felts are not known.
Prefabrication or precutting of felts for installation by the manufacturer may
minimize field cutting but may not be feasible or necessary, considering the
possibly increased product cost and the low occupational exposures at
concentrations of 0.1 f/cm^. Containment of installation and removal
operations would be economically infeasible due to cost of building
containment structures and of controlling the inevitable increase in
occupational exposures. Wetting with amended water has been mentioned as a
probable control; however, actual studies have not been reported.21
4-33
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4.4.5 Removal of Nonfriable Insulation
Again, wetting with amended water is mentioned as a probable control
method of occupational exposures resulting from removal of textile and paper
insulation products.21 Containment procedures may also be possible as
described for removal of friable asbestos insulation.14 cleanup work
practices that include wetting scrap, wet sweeping, and vacuuming also provide
for emission control.
4.4.6 Encapsulation with Sealants
Application of a sealant to friable asbestos materials by spraying will
disseminate small fibers by contact. A sealant should be applied with as much
caution and at as low a nozzle pressure as possible to reduce contact
disturbance. The potentially high concentration of small asbestos fibers
could cause significant worker exposure, so workers require protection with
respiratory devices and decontamination. Such asbestos fiber contamination
from application of sealants is usually not detectable by the National
Institute for Occupational Safety and Health (NIOSH) method of optical
microscopy and may require electron microscopic examination for definition.14
4.4.7 Renovation and Demolition
Asbestos emissions resulting from renovations and removal of friable
materials containing asbestos are controlled by use of amended water prior to
scraping, picking, and drilling and by containing emissions within areas where
removal is undertaken. Demolition control procedures include removal of
friable materials containing asbestos, removal of nonsupport installations
covered with friable asbestos materials such as boilers, and spraying of the
building with water prior to wrecking.
4.5 WASTE DISPOSAL
The processes involved with asbestos-containing materials in construction
are fabrication, renovation, or demolition operations. However, fabrication
of asbestos products for installation is not covered by the current EPA
standard. In its definition of fabrication, EPA has exempted fabrication
of products "at temporary sites for the construction or restoration of
buildings, structures, facilities, or installations." However, 61.22 (j) of
the current NESHAP for asbestos applies to the friable materials removed in
renovation and demolition operations. Therefore, asbestos-containing waste
4-34
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from these operations either is treated with water, sealed with leak-tight
containers, and buried or is formed into nonfriable pellets or shapes.
At construction sites, waste includes A/C pipe, sheet and panel scrap,
and dust collected by local exhaust systems or any other means from cutting
and drilling operations. Waste includes ripped out roofing and drywall,
roofing felt pieces left from installation, and dust collected by vacuum
systems or wet-sweeping during cleanup. Nonfriable insulation such as paper
and textile scrap used in electric generating plants, on pipe and ducts, also
will be construction waste. Waste also will include pieces of floor tile and
flooring felts left after installation and empty and near-empty cans, barrels,
or drums of asbestos-containing coatings and sealants. However, only the
friable materials containing asbestos removed from buildings are covered under
waste disposal provisions of the standard.
4.6 COSTS
Some cost data are available from economic analysis of the occupational
standard. Equipment designed to control emissions from drilling or cutting
A/C products may cost from $400 to $3,000.5 Industry's total annualized cost
for engineering controls"for a 2.0-f/cm^ occupational exposure limit is
between $1 and $9 million.
Surfactants for making amended water might cost between $15 and $18 per
gallon, and 1 ounce of surfactant to 5 gallons of water is the recommended
usage.^ Therefore, the cost of amended water in renovation and demolition
will depend upon the size of the job and the amount of friable asbestos to be
removed. According to Sawyer, the cost of removing and disposing of a ceiling
containing a sprayed-on asbestos cement covering costs $42,962 or $1.23 per
square foot.*4
The cost of removing sprayed-on asbestos materials in 27 Massachusetts
public schools ranged from $0.91 to $14.00 per square foot.13 •
4.7 STATUS OF OCCUPATIONAL HEALTH STANDARD
The Occupational Safety and Health Administration (OSHA) standard for
asbestos [29 CFR 1910. 1001] is applicable to the construction industry and is
currently under review by the Agency. The review has been projected to take
at least 2 years. The current permissible exposure level is 2 f/cm^.
4-35
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4.8 REFERENCES
1. Bureau of the Census, U.S. Department of Commerce. 1977 Census of
Construction Industries, Summary.
2. JACA and National Association of Demolition Contractors (NADC) Project
Summary and Report of First Year Grant Activities. (Prepared for the
Occupational Safety and Health Administration, U.S. Department of Labor,
Washington, D.C.) June 1979.
3. Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency. Background Information on National Emission Standards
for Hazardous Air Pollutants, Proposed Amendments to standards for
Asbestos and Mercury. Research Triangle Park, North Carolina.
EPA-450/2-74-009. October 1974. p. 140.
4. The Research Corporation of New England. Demolition and Renovation.
Cost of Complying with EPA Asbestos Regulations. Wethersfield,
Connecticut. (Prepared for the U.S. Environmental Protection Agency.)
August 1979. 92 p.
5. Kendall, D. L., et al. Economic Impact Analysis of Controls on Certain
Use and Exposure Categories of Asbestos (draft). Research Triangle
Institute. (Prepared for the Office of Toxic Substances, U.S.
Environmental Portection Agency. Research Triangle Park, North
Carolina.) November 1980.
6. Lee, B. S., et al. Asbestos Dust. Technological Feasbility Assessment
and Economic Impact Analysis of the Proposed Federal Occupational
Standard. Part II: Economic Appendix, Asbestos Dust in Construction.
Research Triangle Institute. (Prepared for the U.S. Department of Labor,
Occupational Safety and Health Administration, Washington, D.C.)
September 1978.
7. Wright, M. D., et al. Asbestos'Dust. Technological Feasbility and
Economic Impact Analysis of the Proposed Federal Occupational Standard.
Part I: Research Triangle Institute. (Prepared for the U.S. Department
of Labor, Occupational Safety and Health Administration, Washington,
D.C.) September 1978. p. 111-13 to 111-54.
4-36
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8. Reference 7, p. 11-13.
9. Reference 5, p. 78-86.
10. Meylan, William M., et al. Chemical Market Input/Output Analysis of
Selected Chemical Substances to Assess Sources of Environmental
Contaimination. Task III: Asbestos. Syracuse Research Corporation.
(Prepared for the Office of Toxic Substances, U.S. Environmental
Protection Agency, Washington, D.C.) August 1978.
11. Conrad, L. Personal communications with Quality Roofing Company. Randy
Bolton. Durham, North Carolina. July 29, 1981.
12. Conrad L. Personal communications-with the Association of Wall and
Ceiling Industries. Gene Irwin. Washington, D.C. July 29, 1981.
13. Irving, Karen, et al. Asbestos Exposure in Massachusetts Public Schools.
American Industrial Hygiene Association Journal. 4Jj270-276. April
1980.
14. Sawyer, Robert N; Asbestos-Containing Materials in School Buildings: A
Guidance Document. Part II. (Prepared for the Office of Air and Waste
Management and the Office of Air Quality Planning and Standards, U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina).
EPA-450/2-78-014. March 1978.
15. Reitz, William. Application of Sprayed Inorganic Fiber Containing
Asbestos. Occupational Health Hazard. American Industrial Hygiene
Association Journal. ^3_:178-191. March 1972.
16. Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency. Background Information on Development of National
Emission Standards for Hazardous Air Pollutants: Asbestos, Berylluim,
and Mercury. APTD-1503. Research Triangle Park, North Carolina. March
1973. p. 97.
17. A/C Pipe Producers Association. Recommended Work Practices for A/C Pipe.
Arlington, Virginia. 1977. p.20.
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18. Asbestos Information Association. Recommended Work Practices for Field
Fabrication of Asbestos-Cement Sheet. Arlington, Virginia. January
1980. p. 27.
19. Reference 7, p. IV-65 to IV-69.
20. Reference 5, p. 150.
21. Reference 7, p. VI-24.
4-38
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5. CONTROL METHODS
Methods potentially applicable for control of asbestos emissions are
discussed in this chapter. Technological advances in fabric filtration,
scrubbing, and electrostatic precipitation as they apply to controlling
particulates and developments in emission control methods for the demolition,
renovation, and construction industry are reviewed. Finally, substitutes for
asbestos and asbestos products are examined as another method for preventing
asbestos emissions. Detailed information on controls already in widespread
use in the asbestos industry are not presented (see Chapters 3 and 4 for
discussions of controls currently used in the asbestos industry). However,
principles of operation and current use of fabric filters (the predominant
control method) scrubbers, and electrostatic precipitators (ESP) are
sunmarized for background information.
5.1 FABRIC FILTERS
Housed in a structure known as a baghouse, fabric filters are one of the
most effective methods for removing solid particles from gas streams. During
filtration, a dust-laden gas stream is passed through a woven or felted
material in the shape of a cylindrical or flat supported bag, depositing dust
on the dirty side of the filter. Dust is deposited on the filter by direct
interception, inertial impaction, diffusion, electrostatic attraction,
gravitational settling, and sieving. A mat or cake of dust forms on the
filter surface, improving its collection efficiency. Eventually, the combined
resistance to air flow of the filter and filter cake increases to the point
that air velocity across the filter and in the entire exhaust system
decreases. At some predetermined resistance level (determined by pressure
drop across the filter), the filters are cleaned by one of a variety of
cleaning mechanisms. These cleaning mechanisms are a distinguishing feature
among baghouse designs.
Filters may be cleaned by fabric flexing or reverse air flow. Fabric
flexing can be accomplished by manual, mechanical, or air shaking. Air
5-1
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shaking is further separated into air bubbling, jet pulsing, reverse air
flexing, and sonic vibration. Reverse air flow consists of three methods:
repressuring cleaning, atmospheric cleaning, and reverse-jet cleaning. For
each of these methods, advantages and disadvantages exist that must be
considered in the overall design of a fabric filtration system for each
industrial application.
A variety of filter material is available; actual selection is determined
by factors such as gas stream temperature and moisture, available space,
cleaning method, and costs. Fabric filter cloth is either woven or felted.
Woven fabrics generally operate at lower air-to-cloth ratios than do felted
fabrics, therefore requiring more cloth area for the same amount of exhaust
gas. Felted bags are used in reverse-jet and pulse-jet baghouses.
A survey of plants that used asbestos revealed that 80 percent of the
respondents used baghouses and 90.1 percent of all control devices used were
baghouses.1 In addition, another 4.4 percent of the plants used baghouses
preceded by cyclones, a combination representing 3.2 percent of total control
devices used. Table 5-1 summarizes the information on control device use,
including baghouse use.
The same survey showed that cotton was the fabric used in the majority of
baghouses (see Table 5-2) and mechanical shaking the cleaning method used most
often (see Table 5-3). Air-to-cloth ratios ranged from 1 foot per minute to
over 10 feet per minute (see Table 5-4). Ratios for mechanically shaken
baghouses were generally less than 3 to 1, while reverse-jet baghouses had
air-to-cloth ratios of 4 to 1 and greater. Pressure drops for a majority of
the baghouses surveyed operated were under 3 inches of water (see Table 5-5).
During 1981, information on emission controls was collected during visits
to 13 milling, manufacturing, and fabricating sites that used over 120
separate control devices (see Table 5-6). Detailed information was not
available in all instances, but baghouses were overwhelmingly used to control
asbestos emissions, as shown in Table 5-7. The cyclone used in conjunction
with a baghouse acted to return scrap material to the process and to reduce
the load on the baghouse. The wet scrubber, with a pressure drop of 1.5
inches, was used to control emissions from a high-moisture, exhaust gas
stream. Table 5-8 summarizes the information collected on baghouse cleaning
5-2
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TABLE 5-1. DUST CONTROL DEVICES1
Plants
using device
Control device
Baghouse
Scrubber
Cyclone-baghouse combination
Cyclone
Filter systems
Scrubber-baghouse combination
No.
72
6
4
4
3
1
Percent
80.0
6.8
4.4
4.4
3.3
1.1
Total
devices used
No.
335
8
12
7
6
4
Percent
90.1
2.1
3.2
1.9
1.6
1.1
Total
90
100.0
372
100.0
5-3
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TABLE 5-2. BAG FABRIC1
01
I
Plant Baghouses using Bag-cleaning mechanism used with
using fabric fabric type of fabric, no. (%) of baghouses
Fabric
Cotton
Dacron
Polyester
Canvas
Wool
Nylon
Orion
Polyprolene felt
Polyphrone felt
Burlap
Total
No.
36
8
5
2
2
1
1
1
1
1
58
Percent No.
62.3 164
13.8 31
8.6 15
3.4 4
3.4 2
1.7 4
1.7 3
1.7 3
1.7 1
1.7
100.0 227
Hand Automatic Reverse Pulse
Percent shaker shaker jet jet
72.2 27 125 10 2
(16.4) (76.8) (6.7) (1.2)
13.7 23 3 5
(74.2) (9.7) (16.1)
6.6 -- 5 10
(33.3) (66.7)
1.8 4
(100.0)
0.9 2
(100.0)
1.8 4
(100.0)
1.3 3
(100.0)
1.3 -- -- 3
(100.0)
0.4 -- 1
(100.0)
--
100.0
-------
TABLE 5-3. BAG-CLEANING MECHANISM1
Cleaning mechanism
Automatic shaker
Pulse jet
Reverse jet
Hand shaker
Total
TABLE 5-4.
Air-to-cloth ratio
m/mi n ft/mi n
£0.62:1 £2.0:1
0.63-0.75:1 2.1- 2.5:1
0.76-0.91:1 2.6- 3.0:1
0.92-1.24:1 3.1- 4.0:1
1.25-3.10:1 4.1-10.0:1
PI
using
No.
39
10
9
8
66
AIR-TO-CLOTH
ants
mechanism
Percent
59.0
15.2
13.6
12.2
100.0
RATIO1
Plants having
ratio
No.
3
3
6
2
7
Percent
14.3
14.3
28.6
9.5
33.3
Baghouses using
mechanism
No.
160
28
33
32
253
Percent
63.3
11.0
13.1
12.6
100.0
Baghouses
having ratio
No.
22
22
23
9
34
Percent
20.0
20.0
20.9
8.2
30.9
Total
21
100.0
110
100.0
5-5
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TABLE 5-5. PRESSURE DROP ACROSS BAG1
Bag-cleaning mechanism used
Plants Baghouses no. (%)
having Ap3 with Ap
Pressure drop Hand Automatic
(cm [in.] H20) No. Percent No. Percent shaker shaker
Ap < 2.54 (1) 2 10.0 2 2.0 -- 2
(100.0)
2.54 (1) < Ap < 5.08 (2) 3 15.0 40 39.2 7 16
01 (17.5) (40.0)
cr>
5.08 (1) < Ap < 7.62 (3) 5 25.0 17 16.6 -- 11
(64.7)
7.62 (3) < Ap < 10.2 (4) 10 50.0 43 42.2 7 26
(16.3) (60.4)
Reverse
jet
__
10
(25.0)
4
(23.5)
4
(9.3)
Pulse
jet
._
7
(17.5)
2
(11.8)
6
(14.0)
Total 20 100.0 102 100.0
aAp = pressure drop.
-------
TABLE 5-6. PROCESSES AND NUMBER OF SITES VISITED
Process
Number of sites visited
Mill ing
Asbestos/cement (A/C) products
Textile products
Plastic materials
Friction products
Paper and felt
Chlorine
3
2
2
1
2
2
1
Total
13
TABLE 5-7. CONTROL DEVICE USE3
Control device
Baghouse
Cyclone-baghouse combination
Scrubber
Otherb
Number of pi ants
using device
11
1
1
2
Total
devices used
120
1
1
1
Information was collected during 1981 plant visits.
bOne plant using a small amount of asbestos uses high-efficiency particulate
air (HEPA) filters. Because of the nature of its product and its
manufacturing process, another plant virtually has eliminated emission
sources from within the plant, thus eliminating the need for air pollution
control equipment for asbestos emissions.
5-7
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TABLE 5-8. BAGHOUSE-CLEANING MECHANISMS3
Baghouses
Cleaning mechanism Number Percent
Pulse jet 83 68
Reverse air 10 8
Shaker 29 24
Total 122 100
Information was collected during 1981 plant visits.
5-8
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mechanisms. Reverse-jet cleaning was used in 68 percent and shaker mechanisms
were used in 24 percent of the baghouses.
Advances in fabric filtration technology during recent years have been
limited to introduction of fabrics capable of withstanding high temperatures
and use of pneumatic cleaning devices.2 Attempts are being made to augment
the already high collection efficiency of baghouses through application of
electrostatics and optimization of baghouse operations.
High exhaust temperature is not a serious problem for the asbestos
industry. High temperatures are associated with drying of asbestos ore during
milling. Nomex fabric filters typically are used for cleaning dryer exhausts
in the mills visited.
The only other major advance or change that has occurred is the apparent
increase in use of reverse-jet filters in the asbestos industry. Generally,
lower overall costs have made reverse-jet fabric filters increasingly popular
wherever dust is collected from industrial processes.3 Pulse-jet cleaning
requires use of felted fabrics and allows higher air-to-cloth ratios, thus
necessitating fewer bags for the same air flow. Reverse-jet filters typically
have longer bag lives than do mechanically shaken filters. In addition, extra
bags are often installed in shaker-cleaned baghouses to permit the .closing off
of a part of the baghouse for cleaning without interrupting production.*
Potentially available technology applicable to fabric filtration was
explored. Use of electrostatic augmentation to improve filter performance
currently is being investigated. An electrostatic charge applied to exhaust
particles or to filters or the imposition of an electric field across the
fabric reportedly increases collection efficiency and reduces pressure
drop.2>4,5 Reduced pressure drop is apparently due to deposition on the
filter of a more porous filter cake.2 Currently, an electrostatic
augmentation device is being marketed under the trade name "Apitron." In the
Apitron, incoming dust is charged as it passes through a corona in charging
tubes just before entering the open end of the filter bags. The filters and
charging tubes are cleaned by a pulse of compressed air.
However, in some asbestos plants, the need for extra bags in mechanically
shaken baghouses is avoided by scheduling fabric cleaning during normal
production interruptions, sucn as meal breaks and shift changes.
5-9
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In another EPA-sponsored study, a pilot-scale baghouse is being used to
investigate electrostatic augmentation of fabric filtration.6 A reverse-jet
baghouse, electrostatically augmented, is being operated in parallel with a
conventional baghouse (control) to eliminate dust from an industrial boiler
slipstream. The electric field is maintained parallel to the fabric surface;
corona particle charging is not used. Performance of the electrostatically
augmented baghouse has been superior to the conventional baghouse in several
ways, including:
Reduced rate of pressure drop increase during a filtration cycle,
Lower residual pressure drop,
Stable operation at higher face velocities, and
Improved particle removal efficiency.
Reported, low power consumption and modest expenditures for electrical
hardware combined with the ability to operate at increased face velocities
offer a favorable economic projection.
For some asbestos manufacturing operations an intermediate product is
produced, which will be processed further to create a finished product. This
process is often referred to as fabricating or secondary processing.
Fabrication of the intermediate products can liberate asbestos fibers as in
the cutting, grinding, or drilling of millboard, A/C sheet, or brake products.
These operations are similar to the finishing steps in manufacturing and
emissions are controlled in the same way, typically by fabric filtration.
Other fabricating operations are not likely to emit asbestos; e.g., in the
asphalt saturation of asbestos felt for built-up roofing or pipeline wrap, or
in the vinyl coating of asbestos felt for vinyl sheet flooring. Air-cleaning
devices associated with these operations; e.g., high-energy air filters
(HEAFs) used for controlling emissions from asphalt impregnating materials,
are not intended for asbestos control. Use of HEAFs has been investigated for
.controlling emissions from asphalt saturation processes and phenol formaldehyde
baking ovens where emissions are submicron, liquid, tacky particulates.7»8
Applicability of HEAFs to asbestos emission control is unknown.
Although baghouses have a high mass efficiency, they may still release
large numbers of small fibers.1 Thus, research has been performed to optimize
baghouse efficiency by controlling various operating parameters, such as
5-10
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relative humidity, air flow, dust loading, bag type, shake cycle, and series
operations.9>!0 In a pilot-scale study,9 the following qualitative
conclusions were drawn:
Relative humidity may affect the longer fibers' filterability, and
nigh relative humidity adversely affects many bag fabrics;
Total dust loading is less significant than dust type;
Cotton fabrics seem equal in control capability and superior in
resistance to relative humidity;
Increasing air-to-cloth ratios (ranges selected in study) promote
fiber removal;
Higher shake amplitudes produce lower outlet concentrations;
Shorter shake durations produce lower outlet fiber concentrations;
Longer time periods between shake cycles (low frequency) produce
Tower outlet fiber concentrations;
Exhaust recycle during bag stabilization may dramatically reduce
outlet fiber concentration during stabilization of new bags
(approximately 24 hours of operation); and
TWO baghouses in series are not significantly more efficient than a
single, stabilized baghouse.
Atypical baghouse was selected, automated, and modified for stack sampling in
a subsequent field study to assess the impacts on baghouse efficiency of shake
amplitude, shake duration, and interval between shaking.^ The conclusion was
that long intervals between shaking, small shake amplitude, and short shake
duration are apparently related to lower emission concentrations. Low
emissions were thus related to the least frequent bag disturbances.10
5.2 WET COLLECTORS
Water and other liquids are employed in conventional, wet collectors to
entrap and remove particulates from gas streams. This action is accomplished
by bringing droplets of scrubbing liquid into contact with the undesired
entrained particles primarily through inertia! impaction, diffusive
deposition, and direct interception to render particle sizes large enough to
permit high-efficiency collection. The mixture of collected material and
scrubbing liquor is removed from the cleaning device to minimize reentrainment
of the original contaminating material. Spray chambers, centrifugal spray
scrubbers, impingement plate scrubbers, venturi scrubbers, packed-bed
scrubbers, and centrifugal-fan wet scrubbers are among the many types of wet
collectors used commercial ly.H> 12
5-11
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A primary disadvantage of using wet collectors as final-stage gas-
cleaning devices to control asbestos emissions is the apparent low collection
efficiency for submicron particulates. Some wet collectors; e.g., the venturi
type, can be designed for improved efficiency in collection of submicron
particle sizes, but operating costs become excessive due to the resultant
higher pressure drops across the scrubbers. Wet collectors also produce a
wastewater discharge. By 1983, asbestos-processing plants must have zero
discharge of asbestos-contaminated wastewater.
Table 5-1 indicates the limited use of wet collectors (scrubbers) by the
asbestos industry as of 1974. Table 5-7 shows the number of scrubbers in use
at 13 sites visited during 1981.
Because of the high energy requirements of conventional scrubbers,
especially in collecting submicron particles, alternate collection forces have
been investigated and applied to augment conventional scrubbers. Presently,
two alternatives are available: electrostatic augmentation and use of
phoretic forces. Electrostatic augmentation includes charged particle,
oppositely charged droplet; charged particle with image charge on droplet;
and charged droplet with image charge on particle.12 phoretic forces are
active in wet scrubbers when temperature or water vapor concentration
gradients exist between the particle and droplet environments.^
5.3 ELECTROSTATIC PRECIPITATORS
In an ESP, a corona is established between an electrode maintained at
high voltage and a grounded collecting surface. Particulate matter passing
through the corona is subjected to intense bombardment of negative ions that
flow from the high-voltage electrode to the grounded collecting surface. The
particles thereby become highly charged within a fraction of a second and
migrate toward the grounded collecting surfaces.13
ESPs are not used by the asbestos industry to control emissions. High
installation cost and lower collection efficiencies (relative to those of
fabric filters) do not make ESPs attractive for control of asbestos
emissions.
5-12
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5.4 DEMOLITION, RENOVATION, AND CONSTRUCTION
5.4.1 Demolition and Renovation
The asbestos national emission standard requires that all asbestos
materials be wetted before being stripped or removed during demolition or
renovation. When temperatures are below 0° C, the wetting requirement is
suspended because of hazardous conditions that would result from freezing
water. Removal techniques currently available and in use to an undetermined
extent include:
Use of wetting agents (amended water),
Use of barriers,
Use of HEPA filtered vacuum cleaners, and
Use of negative air pressure.
Wetting agents added to water enhance its penetration, reduce the amount
needed, and generally increase control effectiveness.14 With the use of
amended water, little water runoff occurs and much is absorbed by fallen
debris, visible dusting is rare, and work time is halved because less time is
necessary for airborne asbestos levels to return to background levels.15
Table 5-9 compares asbestos fiber counts for three removal methods.
Concentrations ?n the tables were obtained through the U.S. Public Health
Service membrane filter method and represent worker exposure levels. Fiber
release is substantially reduced with use of amended water over fiber release
encountered with either dry or wet (and untreated water) methods. A wetting
agent of 50 percent polyethylene ester and 50 percent polyoxyethyl ene ether in
a concentration of 30 milliliters (1 ounce) in 19 liters (5 gallons) of water
was used to obtain results shown in Table 5-9.
Barriers, consisting of polyethylene sheets, can be used to avoid
contamination of adjacent rooms and the surrounding community.*5 Polyethylene
sheets are placed over all openings surrounding the work area, which can be a
single room or an entire building. Barriers can be used to reduce
contamination in both dry and wet removal of asbestos. Table 5-10 presents
the results of using two parallel polyethylene sheets taped to door jambs to
prevent movement of asbestos fibers from the work area to an adjoining room
and to an outer room.
5-13
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TABLE 5-9. COMPARISON OF METHODS IN REMOVAL OF AN 8- x 12-FOOT CEILING
SECTION^
Dry:
Wet:
Wet:
Method
no preparation
untreated water
amended water
Number of
sampl es
11
6
10
Asbestos fiber counts
Mean
82. 2a
23.1
8.1
(f/cm3)
Standard
deviation
24.7
4.9
4.6
aMembrane filters contained numerous fiber clumps in addition to counted
fibers.
TABLE 5-10. INHIBITION OF ASBESTOS- MOVEMENT BY POLYETHYLENE BARRIERS15
Mean fiber counts (f/cm^)
Inner room
Removal method (demolition)
Middle room
(entry)
Outer room
(staging)
Dry
Amended water
74.4
8.2
6.4
2.0
2.0
0.0
5-14
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Dry vacuum methods can be used for rapid removal of fallen debris and
decontamination of work areas after the bulk of asbestos material is removed.
Passing the vacuum exhaust through a HEPA filter is recommended.14 A HEPA
filtered vacuum will fail if used on wet material,16 preventing its use for
removing wetted debris. Commercial vacuum systems are available for dry and
wet asbestos removal. Typically, such a system is mounted on a truck with a
heavy-duty, reinforced vacuum receiving chamber. The vacuum is equipped with
three major filtration devices, and the storage section is equipped with a
sprayer to treat collected dust. The system uses exhaust filtration
(including a HEPA filter) and a vacuum blower.
The negative air pressure method requires that the work area first be
isolated with a system of barriers, as previously mentioned. Fans are
positioned to draw air from the work area through HEPA filters before the air
is exhausted to outside air. One such system currently available is
"Micratrap," which is designed specifically for asbestos removal. Filter
replacements are $100 each and have approximately a 1,000-hour operating
life.
The United States Navy currently is supporting the design, development,
and construction of asbestos control chemicals and prototype equipment for
removal of asbestos thermal insulation from ships. The technique involves the
injection of an impregnating fluid into the insulation; determination of
saturation of the insulation using electrical conductivity; and application of
a foam or gel as the insulation is cut for removal. Trials of the system will
be conducted in actual shipboard situations. The method is designed to reduce
fiber levels well below the current Occupational Safety and Health
Administration (OSHA) limits.
In certain situations, use of encapsulants or sealants offers an
alternative to asbestos removal. Because encapsulation is not a control
method to be used during demolition or renovation, it is discussed only
briefly here. Encapsulation might be used where a building is not being
renovated or demolished but where asbestos insulation is discovered in the
building and removal would be extremely difficult. It would not apply to
demolition jobs or where asbestos-covered surfaces are being removed as part
of renovation.
5-15
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Sealing sprayed asbestos surfaces involves applying material that will
envelop or coat the asbestos fiber matrix, eliminate fallout, and protect
against contact damage. Sealants usually are applied to asbestos surfaces by
spraying and consist of polymers with an agent added to enhance penetration
into the fiber matrix. Currently available sealants include water-based latex
polymers, water-soluble epoxy resins, and organic-sol vent-based polymers of
various types.14
Application of a sealant to friable asbestos by spraying will disseminate
small fibers by contact. A sealant should be applied with caution and at the
lowest nozzle pressure possible to reduce contact disturbance.^
EPA's Chemical Control Division, Office of Pesticides and Toxic
Substances, currently is sponsoring work to study and evaluate new or
innovative asbestos removal methods. In the first study phase, which is not
complete yet, the availability of alternative removal methods is being
investigated. During the second phase, various removal methods will be
monitored to determine which produce lower emission levels.
5.4.2 Construction
In construction, operations that would be expected to release fibers into
the atmosphere (e.g., cutting A/C pipe or sheet, removal of built-up roofing,
and others) generally do not occur 8 hours a day, 5 days a week.17 Potential
emission sources include installation of A/C pipe, A/C sheet, A/C
architectural panels, and built-up roofing.
Local exhaust ventilation (LEV) systems connected to a vacuum source are
available for power grinding, sanding, cutting, and drilling tools. However,
because these tools cannot endure field conditions, they are not used in
significant numbers by the construction industry.1? Furthermore, the
effectiveness of the LEV systems is closely associated with operator
techniques and the geometry of the LEV's hood. LEV's effectiveness may
decline drastically if the hood is damaged, which is likely in field use of
such equipment.17 The cost associated with a LEV system and vacuum unit for a
circular saw ranged from $1,400 to $3,000, according to a technological
feasibility study.17 The efficiency of the vacuum unit associated with LEV
depends on the vacuum filtering system. Vacuum systems are available with
HEPA filters and would be expected to have high dust control efficiencies.
5-16
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Vacuum filters have been developed that are capable of collecting 99.97
percent of all dust down to the 0.3- to 0.5-micrometer particle size range.18
Alternatives to power tools exist for field cutting and machining A/C
pipe. Field cutting tools especially designed for A/C pipe are available,
which may be hand operated or driven by electric, gasoline, or pneumatic
motors. A study of worker exposure to asbestos using manual machining lathes,
snap .cutting equipment, a hack saw, and a tapering tool showed that worker
exposure levels were below 0.5 f/cm^ (>5 micronmeters long, National Institute
of Occupational Safety and Health [NIOSH] method).19 These tools are already
used by some contractors installing A/C pipe and result in little lost
productivity compared to losses generated by a shrouded circular saw, which
requires additional time and skill on the part of the employee to, perform.!7
In 1978, the cost of machining tools ranged from $350 to $1,500 (depending on
size range) and the cost of cutters ranged from $900 to $1,300.
Wet cutting is a control technique that injects water onto the contact
point between the saw blade and the product being cut; however, there is no
indication that this method has been used under field conditions.17
5.5 SUBSTITUTES
Detailed assessments of the economic and technical potential have been
performed recently for many nonasbestos substitute materials.l7»20,21 such an
assessment will not be repeated here; rather, the status of substitutes will
be summarized.
Substitutes for asbestos products have been operating in the market place
for several years and substitute materials are available for many
applications. However, no substitute material currently is able to replace
asbestos in all of its applications. Where substitutes are available, they
may be more costly and le.ss desirable than asbestos. Factors that have
encouraged the search for suitable substitutes include:
Significant price increases for asbestos;
Significant worldwide shortage of asbestos fiber,
Concerns regarding health effects of exposure to asbestos,
Health concerns regarding use of certain asbestos-containing
products (e.g., drywall spackling compounds),
5-17
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Administrative burdens imposed by OSHA's current standard for
occupational exposure to asbestos,
Increased workers' compensation costs,
Increased incidence of common law product liability suits,
Increased difficulty in obtaining product liability insurance
coverage, and
Increased adverse publicity regarding health effects of asbestos.17
Added to this list should be increasing regulations by several Federal
agencies. It should be mentioned that concern exists that any substitute will
pose its own health hazards to the producing industries and to the product
users.
Listed below are the asbestos-containing products judged, in one study,
to face competition from nonasbestos substitutes:
Vinyl/asbestos (V/A) resilient flooring
Roofing felt
Transmission paper
Filter paper
Electrical wire wrapping tape
Industrial laminates
Decorative laminates
Millboard and roll board
Commercial paper
Disc brakes for automobiles and light trucks
A/C pipe
A/C sheet
Reinforced plastics
Coatings, paints, and sealants
Gaskets and packings not for high-temperature applications
Thermal insulation
Drilling fluid additives
Asphalt paving cement
Shotgun shell wadding
Joint cements and patching compounds.20
Five asbestos-containing products judged to face no market competitors in an
economic sense included:
Pipe!ine wrap,
5-18
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Electrolytic cell diaphragms,
Electrical paper,
Drum brake shoes for automobiles and light trucks, and
Gaskets and packing for high-temperature applications.20
Some qualifications are needed here. For example, some automobiles and light
trucks are equipped with four-wheel disc braking systems that are asbestos
free.20
The competitiveness of substitutes for two asbestos-product categories,
metal lining paper and textiles, could not be determined clearly based on
available data.20
5.6 REFERENCES
1. Harwood, C. F., P. Siebert, and T. P. Blaszak. Assessment of Particle
Control Technology for Enclosed Asbestos Sources. Office of Research and
Development, U.S. Environmental Protection Agency. Research Triangle
Park, North Carolina. EPA-650/2-74-088. October 1974. 126 p.
2. Ariman, T., and D. J. Helfritch. Pressure Drop in Electrostatic Fabric
Filtration. In: Second Symposium on the Transfer and Utilization of
Particulate Control Technology. Volume III. Particulate Control
Devices, Venditti, F. P, J. A. Armstrong, and M. Durham (ed). Research
Triangle Park, Industrial Environmental Research Laboratory, Environmental
Protection Agency, EPA-600/9-80-039c. September 1980. p. 222-236.
3. Rymarz, T. M. How to Specify Pulse-Jet Filters. In: Industrial Air
Pollution Engineering, Cavaseno, V. (ed). New York, McGraw-Hill
Publications Company. 1980. p. 197-200.
4. Frederick, E. R. Fibers, Electrostatics, and Filtration: A Review of
New Technology. Journal of the Air Pollution Control Association.
30:426-431. April 1980.
5. Lamb, G. E. R., and P. A Costanza. A Low-Energy Electrified Filter
System. Filtration and Separation. July/August 1980. p. 319-322.
6. Van Osdell, D. W., G. P. Greiner, G. E. R. Lamb, and L. S. Hovis.
Electrostatic Augmentation of Fabric Filtration. In: Third Symposium on
the Transfer and Utilization of Particulate Control Technology.
Research Triangle Park, Environmental Protection Agency. March 9-12,
1981. 10 pp.
5-19
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7. Goldfield, J., V. Greco, and K. Gandhi. Glass Fiber Mats to Reduce
Effluents from Inudstrial Processes. Journal of the Air Pollution
Control Association. 2^:466-469. July 1970.
8. Goldfield, J., and K. Gandhi. Influence of Fiber Diameter on Pressure
Drop and Filtration Efficiency of Glass Fiber Mats. Journal of the Air
Pollution Control Association. J33J95-97. January 1981.
9. Siebert, P- C., T. C. Ripley, and C. F- Harwood. Assessment of Particle
Control Technology for Enclosed Asbestos Sources—Phase II. Office of
Research and Development, U.S. Environmental Protection Agency. Research
Triangle Park, North Carolina. EPA-600/2-76-065. March 1976. 125 p.
10. Jones, D. R. Optimizing Baghouse Performance to Control Asbestos
Manufacturing Source Emissions (draft). ITT Research Institute.
(Prepared for Industrial Environmental Research Laboratory, U.S.
Environmental Protection Agency. Cincinnati, Ohio.) EPA Contract Number
68-03-2558. 1980. 64 p.
11. Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency. Control Techniques for Asbestos Air Pollutants.
Research Triangle Park, North Carolina. EPA Publication Number AP-117.
February 1973.
12. Genoble, A. L., R. L. King, and J. L. Pearson. Scrubber Emissions
Correlations. Engineering-Science. (Prepared for Stationary Source
Enforcement, U.S. Environmental Protection Agency. Washington, D.C..)
EPA Contract Number 68-02-4146, Task Order 49. December 1979.
13. National Air Pollution Control Administration. Control Techniques for
Particulate Air Pollutants. Publication No. AP-51. Washington, D.C.
January 1969. 215 p.
14. Sawyer, R. N., and C. M. Spooner. Sprayed Asbestos-Containing Materials
in Buildings: A Guidance Document. Yale University and GCA Corporation.
Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency. Research Triangle Park, North Carolina.
EPA-450/2-78-014. March 1978. 133 p.
15. Sawyer, R. N. Asbestos Exposure in a Yale Building. Environmental
Research. 13:146-169. 1977.
5-20
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16. Office of Toxic Substances, U.S. Environmental Protection Agency.
Asbestos-Containing Materials in School Buildings: A Guidance Document.
Part 1. Washington, D.C. March 1979. 64 p.
17. Wright, M. D., et al. Asbestos Dust Technological Feasbility Assessement
and Economic Impact Analysis of the Proposed Federal Occupational
Standard. Part I: Technological Feasbility and Economic Impact
Analysis. Research Triangle Institute. (Prepared for Occupational
Safety and Health Administration, U.S. Department of Labor. Washington,
D.C.) NTIS No. RTI/1370/02-01-F. September 1978.
18. The Nilfisk GA73 Vacuum Cleaner. Asbestos. April 1976.
19. Equitable Environmental Health, Inc. Dust Exposure During the Cutting
and Machining of Asbestos/Cement Pipe. Additional Studies. (Prepared
for the A/C Pipe Producers Association. Arlington, Virginia.) December
15, 1977.
20. Kendall, D. L, et al. Economic Impact Analysis of Controls on Certain
Use and Exposure Categories of Asbestos (draft). Reserach Triangle
Institute. (Prepared for Office of Toxic Substances, U.S. Environmental
Protection Agency. Washington, D.C.) November 1980.
21. Cogley, D., et al. Asbestos Substitute Performance Analysis (draft).
GCA Corporation. (Prepared for Office of Toxic Substances, U.S.
Environmental Protection Agency. Washington, D.C.) March 1980.
5-21
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6. SAMPLING AND ANALYSIS
6.1 SAMPLING CRITERIA
Battelle-Columbus Laboratories studied the feasibility of developing
asbestos source sampling methods and established criteria (summarized in
Tables 6-1 and 6-2) necessary for an asbestos source sampling method. The
first two criteria listed in Table 6-1 place the following constraints upon
the sampling method': the overall collection efficiency must be known over the
fiber diameter range and sufficient numbers of fibrils and fibers must be
collected simultaneously by the same mechanism to eliminate the need for fiber
size separation.^
The production process and applied control technology will affect the
ability to collect a time-integrated sample. Battelle indicated that the
number, concentrations, and size of the fibers may vary throughout the
production processes. This characteristic and the fact that baghouses often
mix the various process emissions (depending upon the design of the control
equipment) and emit particles having a smaller mean size than most process
emissions affect sample concentrations and the ultimate determination of the
sampl ing method.
To obtain a sample from the local environment, the sampling method must
be flexible enough to adapt to several variable occurrences:
Stack environments in which air flow is controlled, uncontrolled
emission environments (i.e., ventilation air leaving plants; indoor
plant air escaping from doors or windows; or outdoor emissions from
mining, transport, and disposal operations);
Temperature,
Relative humidity,
Air flow velocity,
Temporal variations of environmental characteristics, and
Physical accessibility.
6-1
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TABLE 6-1. CRITERIA FOR A SOURCE SAMPLING METHOD FOR ASBESTOS
FOR THE ACQUISITION OF A REPRESENTATIVE SAMPLE
Ability to collect asbestos over the diameter range 0.03 < Df < 10 um
covering fibrils and fibers for determining number and mass
concentration by counting techniques
Ability to collect asbestos fiber bundles over the diameter size range
0.2 um to several tens of micrometers for determining number
concentration by counting
Ability to collect a time-integrated sample
Ability to extract a sample from the local environment
6-2
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TABLE 6-2. CRITERIA FOR A SOURCE SAMPLING METHOD FOR ASBESTOS TO BE COMPATIBLE WITH THE
ANALYTICAL METHOD FOR ASBESTOS DETERMINATIONS
Compatible with the provisional method
Stricily compatible Compatib1e
with recommendations with alternatives
Compatible with
electron microscopy
en
CO
Sample must be collected
uniformly over a 0.4-Mm
pore size polycarbonate filter
Collection filter must have
an asbestos loading in the
proper range for counting
Collection method is air
filtration
Collection medium is 0.4 pin
pore size polycarbonate
filter material
Collection of nonasbestos
matter must be minimized
Special care in the handling
of polycarbonate filters
must be exercised
Fiber bundles must be collected
for counting
Capability to take the collected sample, alter it
(e.g., by"ashing), and obtain a uniform dispersion
on a polycarbonate filter is required
Capability of obtaining an asbestos loading on a
polycarbonate filter in the proper range for counting
is required
Collection method is air
filtration
Collection medium is 0.4 MID
polycarbonate or cellulose
acetate filter material
Collection method is not
limited to air filtration
Collection medium is not
specified; however, it must
be compatible with a
procedure to transfer the
collected asbestos to an
em grid
Capability to reduce the collected nonasbestos material (e.g.,
by ashing) must be available
Polycarbonate filters are not necessarily required for field
use
Counting of fiber bundles is
not necessarily required
-------
6.2 CURRENT SAMPLING METHODS
Battelle reviewed sampling methods that have been used to obtain asbestos
emission samples and methods that have been based upon EPA's Method 17;2 e.g.,
the Canadian standard reference method-^ and the EPA-recommended method that
was used for emission testing of an iron ore beneficiation plant.4 Methods
based on EPA sampling methods for new stationary sources were also
reviewed.455,6,7 Battelle described the method used by Harwood, Oestreich,
Siebert, and Blaszak to sample asbestos emissions from baghouse-controlled
sources including two asbestos/cement (A/C) plants, two mills, and one
asbestos textile pi ant.8 The following comments concern each of the methods
reviewed by Battelle and are excerpted from that report.
The Canadian standard reference method specifies an in-stack filter
in a sampling train that is essentially equivalent to Method 17.
The filter holder and filter must be capable of withstanding
temperatures up to 200° F. A cellulose membrane filter with 0.8
micrometer pore size is required. The probe must have a heating
system capable of maintaining the temperature of the gas at the exit
end of the probe high enough to prevent condensation.
EPA has recommended a method for sampling asbestos emissions, which
is also based on Method 17. Inasmuch as asbestos emissions are not
affected by temperatures below 300° F, the collection temperature of
250° F for total particulate sampling need not be maintained.
Particulate matter may contain condensible material such as
asbestos. Relaxation of this constraint eliminates the necessity of
employing a glass probe and heating system; therefore, the distance
travelled by the fibers going from the stack environment to the
filter is reduced. Because heating is eliminated, this method is no
longer suitable for environments containing saturated water vapor or
liquid drops.
Sampling conducted at iron ore beneficiation plants for fiber
emissions has used both in situ and extractive sampling. Extractive
sampling was used at a dock pellet storage silo ventilator stack
because saturated conditions existed in the stack. The sampling
train was heated from the inlet through the 47-millimeter
polycarbonate filter. Sampling of the baghouse exhausts from the
ore car dump, fine crusher, and fine crusher conveyor-to-
concentrator storage silos was accomplished by in situ filtration.
Except for one test using a cellulose-acetate filter, all tests were
conducted using a 47-millimeter polycarbonate filter. Sampling
duration ranged from 15 seconds to 7 minutes, depending upon
expected loading.
Fugitive emission sampling methods also have been the subject of two EPA
reports reviewed by Battelle.9,10 Battelle summarized the commonly used
strategies in the following comments:
Fiber emission measurements also have been made for pelletizinq
operations. Temperatures at the four locations encountered in
Reference 8 ranged from 100° to 225° F. Deviations from Method 1 to
5 include (1) use of a 115-millimeter cellulose acetate filter
instead of a glass fiber filter, (2) maintenance of 180° F for the
sampling probe and heated filter, and (3) installation of a glass
cyclone in the heated filter box ahead of the filter to remove some
6-4
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particulate material. A temperature of 180°.i- was chosen, after
deterioration of the cellulose acetate material was detected ai
200s F.
Measurements of asbestos emissions from baghouse-controlled sources
have been taken by extractive sampling systems placed upstream of
the baghouses. Samples were drawn through a cyclone prior to
filtration by a 10-centimeter, 0.8-micrometer pore membrane filter.
The cvclone was not used on the downstream side. In some instances,
sampling locations for extractive isokinetic sampling were
inaccessible. High-volume samples with a membrane filter were used
within the baghouse for downstream measurements. A recent study
suggests sampling simultaneously using three filters at different
flow rates in an attempt to ensure proper loading.
The quasi-stack method that involves capturing the entire emission
stream with an enclosure or hood and sampling these confined
emissions with standard stack sampling techniques.
The roof-monitor method that involves measuring the emissions by
traverses across well-defined openings such as ventilators, windows,
and access doors.
The upwind-downwind method that involves measuring upwind and
downwind concentrations using ground-based sampling. Source
strength is calculated using a diffusion model measured by
meteorological parameters.
The exposure-profiling method that involves direct measurement of
particle flux downwind of a source by simultaneous multipoint
sampling over an effective cross section of the fugitive emission
plume. The sampling condition must be isokinetic.
The most common methods for monitoring asbestos emissions use high-volume
filtration with membrane filters. This type of filtration is consistent with
EPA's recommended sampling procedure for its published provisional method.H
In reviewing the literature, Battelle found that passive samplers have
been used to collect particulate matter for particle flux measurements.
However, they reported that although such samplers meet environmental
constraints, an additional constraint on the amount of sample collected is
imposed upon the sampler by virtue of its design. That is, sampling volume is
limited by the product of the effective cross section of the sampler and the
prevailing air velocity. A separate, continuous record of local air velocity
must be maintained to measure airborne concentration, as opposed to particle
flux.
6.3 ANALYTICAL METHODS
Three acceptable approaches are available for analyzing airborne asbestos
fibers. Optical methods, which are limited by fiber lengths of 5 micrometers,
depend upon morphological recognition and optical crystallographical
techniques.12 Electron microscopy methods are capable of examining fibers in
6-5
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sizes less than 0.1 micrometer in diameter. The third approach involves
physical analytical methods; these methods are limited to mass measurements.
6.3.1 Optical Methods
The National Institute for Occupational Safety and Health (NIOSH), the
Province of Ontario, and the Asbestos International Association have endorsed
the optical phase contrast microscopy method. Slight variations appear in
each procedure, although each method requires that the cellulose ester filter
used in the sampling train be treated with solutions having proper refractive
indices to render the membrane filter transparent. The procedure continues
with counting and sizing fibers according to morphological characteristics.
This method's major disadvantage is that it is nonspecific to asbestos and can
be used only to count fibers greater than 5 micrometers in length.
Polarizing microscopy also can be used, although it is used more often by
geologists and mineralogists to identify asbestos in bulk samples.^ Stephen
Becket summarized that this method uses the asbestos molecule polarizability,
which varies along different rotational axes.
6.3.2 Electron Microscopy
Environmental asbestos emissions commonly are fibers less than 1
micrometer in diameter; therefore, optical methods of analysis have limited
usefulness. Scanning electron microscopy (SEN) and transmission electron
microscopy (TEM) provide greater magnification and resolution than do optical
methods for fiber identification, counting, and sizing and are used
extensively to examine asbestos fibers.
SEM methods are comparable to reflected light microscopy but form images
electrooptically.14 Although sampling strategies generally are not
constrained by this analysis, Beckett recommends use of Nuclepore filters
(polycarbonate filters).15 Cellulose ester membrane filters may be used and
are recommended if analysis by both optical and electron microscopy is
required. However, these fibers must be ashed, dispersed, and remounted for
the electron microscope analysis. In addition, some workers have expressed
concern over fiber degradation, fracturing, or other alterations that might
occur during ashing.15 Although other workers have argued that the smooth
collection surface of Nuclepore filters does not adhere to particulate
material during handling and transferring, EPA's provisional method specifies
the use of this filter.
6-6
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After sampling, the filters are mounted onto stubs and shadowed with gold
or carbon to give the fibers a conducting surface. Once mounted, electrons
scan the specimen from which secondary electrons are emitted. These secondary
electrons are amplified and displayed as intensity modulation on a cathode ray
tube. The resulting image appears almost three dimensional. When the
scanning electron microscope is equipped with X-ray analytical instruments,
X-rays emitted from particles can be analyzed either by corresponding energies
or wavelengths. Therefore, pictures of fibers can be produced with the X-ray
spectrum, enabling identification of differing asbestos types.^
Rajhans and Sullivan outlined the advantages of the SEM method: actual
fiber size distribution is preserved, analysis is rapid, and large segments of
a filter can be examined. They found that disadvantages outweighed advantages
in that underlying fibers are not detected, fibers are lost through Nuclepore
membranes, stray X-rays may provide confusing results, analysis of fibrils is
difficult, and the X-ray spectrum may not discriminate between some
asbestiforms.16
TEM methods are capable of examining fibers 0.1 micrometer in diameter.
TEM's imaging capabilities are superior to those of SEM. Sampling techniques
are not constrained; however, TEM is similar to SEM because filter selection
may change preparation and mounting procedures slightly.
Small pore size filters frequently are preferred; however, sizes of 0.8
micrometer have been used successfully.^ $o0n after sampling, Nuclepore
filters are coated with carbon. Collected dust-containing fibers is then
transferred to the TEM grid either by the modified Jaffe-wick technique
recommended by EPA^- or by condensation washing. Transmission electron
microscopes can be equipped with energy-dispersive spectrometers, which
provide resolution morphology, crystal structure, and elemental composition of
fibers.
TEM can be used to provide selected area electron diffraction (SAED)
patterns in which scattered electrons at specific angles are focused at a
single point in the image plane. The image produced on a fluorescent screen
is relative to the crystal structure of the asbestos molecule, and the pattern
obtained from an isolated particle is theoretically that of a single
crystal.17 SAED patterns are similar for each fiber type; therefore, TEM/SAED
6-7
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methods are capable of characterizing crystal structures of amphibole and
chrysotile asbestos and other crystalline mineral particles. However,
chemical analyses may be required in addition to TEM/SAED analysis of some
amphibole structures because some patterns are not readily distinguishable.
TEM/SAED analysis also may present problems with identifying fibers as small
as 20 nanometers and with fibers that are too long.l?
Patterns resulting from chrysotile are unique because they exhibit
prominent layer line spacings. However, only 20 to 50 percent of the sampled
chrysotile fibers provided the correct layer line spacing and less than 15
percent demonstrated the unique chrysotile SAED pattern.8
A scanning transmission electron microscope that combines the advantages
of TEN and SEM19 -js available. This instrument is used in laboratories
specifically for asbestos fiber counting and identification. This
transmission electron microscope allows the electron beam to scan the sample
and to focus on a particular point. The technique generally is applied to
obtain a shadow image like that obtained with TEM and either a diffraction
pattern or X-ray spectrum as needed.
6.3.3 Physical and Chemical Analysis
Several methods have been developed to obtain mass measurements of
airborne dust-containing asbestos. However, mass measurements do not
distinguish between masses of asbestos and other dust, nor do they define size
characteristics directly related to the reported health effects. X-ray
diffraction and infrared spectroscopy have been used to analyze airborne
asbestos-containing dust.21
6.3.3.1 X-ray Diffraction Analysis. Rajhans and Sullivan reported that
various investigations have performed quantitative analysis of asbestos in
filter samples by X-ray diffraction. In 1969, Goodhead and Martindale
developed methods to determine milligram quantities of amosite and chrysotile
in airborne dusts by X-ray analysis. In 1971, Richards and Badomi
demonstrated X-ray methods to determine chrysotile with detection limits as
low as 10 micrometers. Lange and Haartz have developed X-ray analytical
methods for microgram quantities of chrysotile asbestos deposited silver
membrane filters with detection limits of 2 micrometers.21
Rajhans and Sullivan summarized the general steps to be taken for
analysis of environmental samples:
6-8
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The sample filter is ashed and placed in a lithium-glass capillary
tube. The tube is placed in the oath of a collimated X-ray oeam,
rotated to increase the probability that each plane in the . .
crystalline material is at some time in the diffracting position,
and photographed.
The filter can be placed directly in the path of the X-rays by
cutting a section from the sample filter and fastening it to a piece
of glass cut from a microscope slide coated with a thin film of
adhesive (lacquer). The layer of lacquer may cause some scattering
and a small loss in X-ray intensity. After mounting, the glass
slide is attached to the sample holder in the diffractometer with a
spring clip. Alternatively, an unadulterated sample filter can be
held flat on the sample stage by suction applied through an array of
shallow grooves communicating with a central vacuum port.
The filter is ashed and the fibers are electrostatically aligned
parallel to one another and embedded in a thin plastic film.
6.3.3.2 Infrared Spectrophotometric Analysis. In 1975, Becket,
Middleton, and ~r>dgson found that infrared (IR) spectrophotometry can be used
to estimate small quantities of single varieties of asbestos.^0 Therefore,
substances other than chrysotile on prepared sample disks may interfere with
mass determinations of asbestos. However, in 1979, Heidermanns reported an IR
method for determining mass of chrysotile asbestos collected on a vinyl
chloride membrane filter. Raj nans and Sullivan summarized the procedure,
which eliminates errors associated with ashing filters:22
The required amount of sample (about 4 milligrams) for IR analysis
is obtained by punching circular filter sections of known diameter.
The required number of filter sections is transferred to a
centrifuge tube, and acetone is added to dissolve the filter matrix.
The result is a fine dust suspension in acetone.
The suspension is centrifuged for 10 minutes with an oscillating
rotor at 13,000 cycles per minute. The fine dust is deposited on
the bottom of the centrifuge tube.
Excess solvent is siphoned off by using a suction tube, fitted with
a frit.
The residue on the bottom of the tube is dispersed in the remaining
acetone and quantitatively transferred onto a glass filter by
rinsing with pure acetone. After the solvent evaporates, the glass
fiber filter, containing the fine asbestos dust, is dried for
subsequent pellet preparation.
The B=KBr pellet is prepared by drying the glass fiber filter and
transferring it with 600 milligrams dry KBr to a steel cylinder for
subsequent grinding to yield a homogeneous KBr asbestos mixture.
IR absorption bands are measured for quantitative determination.
The characteristic double bond at 3.660 or 3,700 cm"1 has been used.
A linear correlation has been reported between extinction and
asbestos concentration in the range of 1 to 3 milligrams chrysotile
asbestos per 150 milligrams KBr.
Heidermans reports a detection sensitivity of 20 micrometers.
6-9
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6.4 OTHER SAMPLING AND ANALYSIS METHODS
Direct reading instruments are readily available on the market for
instantaneous measurement of airborne dust. The instruments usually employ
light-scattering principles and they normally record all airborne dust,
regardless of its composition.
One such instrument is the Fibrous Aerosol Monitor, Model FAM-1,
developed by GCA Corporation under contract to NIOSH with partial funding from
the U.S. Bureau of Mines and EPA. The following excerpt from Rajhans
and Sullivan's book on asbestos sampling describes the instrument.
The instrument draws air from the environment into a sensing tube at a
rate of 2 liters/min. A laser beam from 2mW He-Ne laser shines down the
tube. The beam volume intersects a region observed by a photomultiplier
detector. Particles that enter the detection volume can scatter light
into the detector. A high voltage electric field is applied to the
detection volume and this field aligns elongated particles such as fibers
perpendicular to the axis of the laser beam. Light is then scattered
from the fibers preferentially in a direction normal to the fiber s long
axis. The electric field is rotated or rocked so that the fiber produces
a series of scattered light pulses as it passes through the detection
volume. These pulses are converted to electrical signals and are
amplified and analyzed by the electronic detection system. Two variables
relating to pulse shape are measured in order to determine whether a
signal is due to a fiber. These two variables are the ratio and the
amplitude and reflect the pulse sharpness and its height. Ratio and
amplitude threshold settings are determined by dial settings on the panel
of the instrument. Once these settings have been established, all
signals meeting the threshold requirements will be counted as fibers-.
The higher the threshold settings', the lower the count rate and the
higher the noise discrimination of the instrument.
Total fiber concentration range is from 0.0001 to 30 fibers per cubic
centimeter for fibers greater than 0.2 micrometer in diameter and 2
micrometers or greater in length.
This instrument has been evaluated by comparison with the NIOSH sampling
and analysis method for work place exposures; its use for emission sampling
has not been tested or evaluated. However, review data reported by the
Illinois Institute of Technology Research Institute (IITRI) on baghouse
emissions (see Subsection 3.5) indicated this instrument would not have
counted 10^ fibers having lengths less than 1.5 micrometers emitted from the
baghouses.
The Royco photoelectric particle counter and the Rathero Mitchell P3
count particulates by using light-scattering principles. The Royco counter
tested in a chrysotile asbestos plant for particles with lengths of 5
micrometers showed counts 25 percent lower than those determined by membrane
filter methods. A 15-percent increase over the counts obtained by membrane
6-10
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fiber methods was found when the Royco counter was set at 4 micrometers.23
The Rathero Mitchell P3 was found unsuitable for monitoring low dust
concentrations.23
Other methods have been developed whereby fibers are counted by first
collecting fibers on membrane filters, aligning the fibers either parallel or
normal to a magnetic field, and measuring scattered light. However, there
are no indications that these instruments have been used to test for asbestos
emissions.
6.5 BULK SAMPLE ANALYSIS
EPA describes three reliable methods whereby asbestos fibers can be
identified from bulk samples: petrographic microscopy. X-ray diffraction, and
electron microscopy.24
6.5.1 Petrographic Microscopy
The petrographic microscope is the same as a polarized light microscope,
which is widely used in the geological and chemical sciences to identify and
characterize crystalline substances based upon their optical and
crystallographic properties. Techniques are well established and equipment is
relatively low in cost. The method is effective for identifying the
particular mineral species present. A possible drawback in the use of
petrographic microscopy is the high level of skill and experience required of
the microscopist. Bulk sample optical microscopy involves the ability to
adequately search a sample and successfully recognize and identify the suspect
material. However, an experienced microscopist should be able to locate and
identify even small amounts of asbestos in bulk samples.
EPA is in the process of publishing its method of analysis for asbestos
in bulk samples using polarizing light microscopy. The method sets down six
criteria to positively identify chrysotile asbestos. This method is limited
to samples containing 1 percent or more of asbestos. The identification is
limited to resolution of the polarizing light microscope, which is capable
of resolving fibers having a length of 2 micrometers, and a diameter of
approximately 0.5 micrometer. Classical methods using refractive index oils
and dispersion staining methods can be applied.
6-11
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6.5.2 X-Ray Diffraction
In this technique, which is also described for emission sample analysis,
X-rays are diffracted by a small sample of the suspect material and a pattern
uniquely characteristic of any crystalline material present is produced. With
some instruments, a permanent diffraction tracing is produced. This method
requires significant investment in equipment, references, mineral standards,
and technical expertise. In routine examinations, X-ray diffraction of bulk
samples may fail to detect small concentrations of asbestos, and other
silicates or crystalline phases may significantly interfere with accurate
identification. However, the technique usually yields information with a high
degree of diagnostic reliability and a printed record. X-ray diffraction
usually is used as a confirmation of petrographic microscopy impressions and
not as a screening procedure.
6.5.3 Electron Microscopy
Specific and accurate fiber identification can be achieved by examining
the structure of individual fibers or fibrils, especially if this examination
is used in conjunction with electron diffraction or energy-dispersive X-ray
analysis. However, extrapolation of precise electron microscope data to
significant bulk sample information is inefficient and costly. Use of these
data in identification usually is confined to resolving ambiguities raised by
petrographic microscopy and X-ray diffraction. Primary use of the
electron microscopy technique is in examination of air samples, which is
described in Subsection 6.3.
6.6 AVAILABILITY OF EMISSION DATA
Few data that characterize asbestos emissions in terms of number, mass
concentration, or size distribution concentrations are available. Some
engineering estimates for yearly asbestos emissions from industrial sources
have been attempted to describe overall environmental exposure to asbestos.
However, estimates have not been provided for all sources, nor have they been
evaluated by monitoring. Emission data most often provided in the literature
are also provided in the earlier chapter of this report.
6-12
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6.7 REFERENCES
1. Battelle Columbus Laboratories. Discussion of Technical Progress.
January 1981.
2. U.S. Environmental Protection Agency. Determination of Particulate
Emissions from Stationary Sources (In-Stack Filtration), Standards of
Performance of New Stationary Sources. Federal Register. 43J37):
7584-7596. February 23, 1978.
3. Fisheries and Enviroment Canada. Standard Reference Methods for Source
Testing. Measurement of Emissions of Asbestos from Asbestos Mining and
Milling Operations. EPS 1-AP75-1. December 1976.
4. Clayton Environmental Consultants. Iron Ore Beneficiation—Emission
Test Report, Reserve Mining Company, Silver Bay- Minnesota. EMB Report
78-10B-5. (Prepared for U.S. Environmental Protection Agency. Research
Triangle Park, North Carolina). 1979.
5. U.S. Environmental Protection Agency. Standards of Performance for New
Stationary Sources. Federal Register. _43(160):41776-41782. August
18, 1977.
6. U.S. Environmental Protection Agency. Standards of Performance for New
Stationary Sources. Federal Register. _45_(160) :41755-41758. August
18, 1977-
7. Reference 6, p. 41,758-41,768.
8. Oestreick, D. K., C. F. Harwood, P. Siebert, and T. P. Blaszak.
Assessment of Particle Control Technology for Enclosed Asbestos Sources.
EPA-650/2-74-088. October 1974.
9. Kalika, P. W., R. E. Kenson, and P. T. Bartlett. Development of
Procedures for the Measurement of Fugitive Emissions. U.S. Environmental
Protection Agency. EPA-600/2-76-284. December 1976.
10. Measurement of Fugitive Particulate. In: Second Symposium on Fugitive
Emissions: Measurement and Control. Houston, U.S. Environmental
Protection Agency. May 1977. EPA-600/7-77-148. December 1977.
p. 47-62.
11. Electron Microscope Measurement of Airborne Asbestos Concentrations; A
Provisional Methodology Manual. EPA-600/2-77-178. Revised June 1978.
6-13
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12. Beckets, S. T. Monitoring and Identification of Airborne Asbestos. In:
Asbestos, Michaels and Chissick (ed.). John Wiley and Sons. 1979.
p. 236.
13. Reference 12, p. 238.
14. National Bureau of Standards. Proceedings of Workshop on Asbestos, July
18-20, 1977- November 1978. p. 222.
15. Reference 12, p. 239.
16. Rajhan, Gyan S., and John L. Sullivan. Asbestos Sampling and Analysis.
Ann Arbor Science. 1981.
17. Reference 16, p. 237.
18. Reference 14, p. 249-268.
19. Reference 14, p. 222.
20. Reference 12, p. 240.
21. Lange, B. A., and J. C. Haartz. Determination of Microgram Quantities of
Asbestos by X-Ray Diffraction: Chrysotile in Thin Dust Layers of Matrix
Material. Analytical Chemistry. _51_(4):520-525. April 1979.
22. Reference 17, p. 181.
23. Reference 12, P. 231.
24. Sawyer, Robert N. Asbestos-Containing Materials in School Buildings: A
Guidance Document. EPA-450/2-78-014. March 1978.
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7. HUMAN HEALTH EFFECTS ASSOCIATED WITH INHALATION
(Jr
7.1 INTRODUCTION
Exposure to asbestos is associated with increased risk of many diseases,
including pulmonary fibrosis (asbestosis), respiratory cancer, and
mesothelioma of both pleura! and peritoneal tissue. These health effects have
been documented in over 90 studies conducted by many researchers using
different groups of occupational workers.i For this document, the health
effects discussion will focus on studies of a quantitative dose-response
relationship for disease among workers exposed only to chrysotile asbestos,
asbestos-related health effects resulting from nonoccupational exposure, and
the influence of cofactors such as smoking habits and age.
7.2 HEALTH HAZARDS OF CHRYSOTILE EXPOSURE
7.2.1 Asbestosis Mortality
Asbestosis is a chronic, noncancerous, irreversible disease characterized
by hardening and thickening of lung tissue. A maj.or cause of death in groups
of workers exposed to high levels of airborne asbestos, asbestosis is a
progressive disease that can continue to develop long after a person has been
removed from the source of exposure. Several occupational studies have
demonstrated dose-response relationships between exposure to asbestos and
severity of asbestosis. The dose-response curve for asbestosis mortality
among Canadian chrysotile miners and millers has been described by McDonald
(1979) as a linear relationship, although the author cautions against
extrapolation to very low exposure levels.2
7.2.2 Lung Cancer Mortality
Many epidemic!ogical studies have demonstrated clearly that lung cancer
risk increases with exposure to asbestos. Few researchers, however, have
attempted to quantify the risk because of problems in estimating cumulative
exposure. Three recent studies—McDonald (1980), Enterline and Henderson
(1979), and Dement et a!. (1980)-- have investigated a quantitative dose-
7-1
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response relationship for lung cancer among workers exposed only to
chrysotile.2.3,4 ^11 three studies suggest that the relationship between
cunulative dust exposure and lung cancer is linear; i.e., the risk of lung
cancer is directly proportional to cumulative exposure. The authors disagree
on the magnitude of increased risk for a given cumulative exposure,
particularly for workers in the lowest exposure categories. Differences in
study design and method of exposure estimation probably account for some
inconsistencies in findings of these three studies.
McDonald (1980), who studied chrysotile miners and millers in Quebec, and
Enter!ine (1979), who investigated mortality of retired maintenance-service
employees of an asbestos manufacturing company, estimated past dust exposure
using work histories and total airborne particulate data collected by the
impinger method.* McDonald included persons exposed to extremely high
airborne fiber levels; thus, competing risk (i.e., persons dying from other
causes) may be a problem. Enterline's study group consisted only of retirees
older than 65 years of age and may represent a survivor population with less
lung cancer risk than the general public. Workers who died before their 65th
birthdays were not included in the study. Both McDonald and Enter!ine found
that risk of respiratory malignancies increases directly with increasing
cumulative exposure but that an excess risk is difficult to detect in the
groups with least exposure.
Dement (1980), who studied mortality among chrysotile textile workers,
used asbestos fiber count data (determined by phase contrast microscopy) to
estimate past exposure. Conditions at the textile plant allowed Dement to
evaluate health effects at exposure levels lower than levels measured by
McDonald or Enter!ine. Dement1s data suggest a linear dose-response
relationship with no threshold for lung cancer and nonmalignant respiratory
diseases. Lung cancer demonstrated a statistically significant excess in
even the lowest cumulative exposure category. The risk of lung cancer at a
given cumulative dose was also found to be greater than the risk reported by
McDonald and Enter!ine.
The impinger method involves pulling a volume of air through a small tube
containing water or alcohol. Particles that settle in the tube are examined
by light microscopy. The impinger method was- replaced by the membrane filter
technique in 1971 for determining occupational exposure to asbestos.
7-2
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7.2.3 Pleural and Peritoneal Mesothelioma
Researchers have shown that exposure to asbestos can produce mesothelioma
of the pleura (the membrane that surrounds the lungs and lines the thorax)
and/or the peritoneum (the membrane that surrounds the abdominal organs and
lines the abdominal and pelvic cavity). Estimated prevalence of mesothelioma
in the United States and Canada ranges from one to six cases per million
people and seems to be higher in cities where asbestos has been used in the
shipbuilding or ship repair industries.5 The disease often is not detected
for 30 to 40 years after initial exposure.
The three studies that quantitatively estimated exposure and lung cancer
among chrysotile workers revealed low mortality due to mesothelioma; Dement
(1980) found 1 death, McDonald (1980) found 11 deaths, and Enter!ine (1979)
found 1 death. In another study, Robinson et al. (1979) observed 17
mesotheliomas amoung 1,040 deaths in a plant using predominantly chrysotile
and some crocidolite and amosite.6
Epidemiologists agree that mesothelioma is underdiagnosed, and proper
study of its incidence requires information beyond what ordinarily appears on
death certificates.3
7.3 NONOCCUPATIONAL EXPOSURE TO ASBESTOS
Perhaps the most disconcerting aspect of the relationship between
mesothelioma and asbestos exposure is the disease's documented association
with apparently low levels of exposure for relatively brief periods from
neighborhood or domestic sources.? In 1960, Wagner documented mesothelioma
cases in residents of a South African asbestos mining area. Many of these
individuals had never worked with asbestos; their exposure was associated with
living near the mines, mills, or roadways along which asbestos fiber was
transported.^ In 1964, Newhouse and Thompson reviewed 76 cases of
mesothelioma reported in London. Roughly half were former employees of an
asbestos manufacturing facility, 11 lived within one-half of a mile of the
asbestos factory, and 9 lived with workmen employed at the factory.9
More recently, Borow et al. (1973), using hospital records rather than
plant records, reported 72 cases of mesothelioma in the vicinity of one of the
two plants Enterline studied.10 Further investigation revealed that 41 of
these cases worked at the plant at some time. Many died before the age of 65
and thus were excluded from Enterline's study groups. Anderson et al. (1976)
7-3
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examined 378 family members of asbestos workers 25 to 30 years after the onset
of initial asbestos exposure. Of these, 239 had one or more chest
abnormalities; five cases of mesothelioma were found in the study group.H In
a case-control study of all female residents of New York State who died of
mesothelioma between 1967 and 1977, Vianna (1978) found that 15 of 62
confirmed cases had worked in asbestos-related industries and 10 had husbands
or fathers who worked in asbestos-related industries.^
Several researchers have shown that asbestos-related diseases are endemic
in some villages in Turkey. Ban's (1975) studied 120 cases of pleura! disease
(108 of which were malignant mesothelioma) and found only 2 with occupational
exposure to asbestos. Of the other 118 cases, 16 had a history of
environmental exposure to asbestos. No condition that may result in asbestos
inhalation was encountered in the rest of the cases, in which it was suggested
that the disease may result from ingestion of water, beverages, or food, or
from other sources.13
Yazialogu (1976) investigated occurrence of pieural calcification '(an
early stage of asbestosis, from which mesothelioma also may develop) among
inhabitants of several southeastern Turkish towns located in areas of
naturally occurring chrysotile. No industrial source of asbestos is located
in the area. Upon examination, 389 individuals (2.6 percent of the total
population) showed pi eural calcifications.^
7.4 FACTORS THAT MODIFY THE RISK OF ASBESTOS-INDUCED DISEASE
7.4., 1 Smoking Habits
The major factor affecting risk of asbestos-induced lung cancer, besides
the intensity and duration of the exposure, is the smoking habit of the
exposed individual. The effects of asbestos exposure and cigarette smoke are
multiplicative, not simply additive (Selikoff et al., 1980).15 Stopping
cigarette smoking is likely to be of paramount importance in reducing excess
cancer risks in asbestos-exposed individuals (Gil son, 1976).16
The scientific community's current consensus is that mesothelioma occurs
with equal frequency among smoking and nonsmoking asbestos workers. Available
studies of asbestos workers are inadequate to determine whether smoking
increases the risk of developing asbestosis.
7-4
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7.4.2 Age
Children exposed to asbestos have greater lifelong risk than adults
equally exposed. The factor can be significant when long latency periods are
encountered for diseases such as lung cancer and mesothelioma. The question
of susceptibility has been raised by some researchers. Kotin (1977) and
Wasserman et al. (1979) suggest that children are more susceptible than adults
are to carcinogens, including asbestos.^.IS Other researchers (Doll, 1962;
Cole, 1977) state that special biological susceptibility has not been
demonstrated for children exposed to asbestos.-^j 20
7.5 FIBER CHARACTERISTICS
7.5.1 Fiber Size
A great deal of research has addressed risk variation posed by fibers
differing in size and chemical composition. Potentially adverse health
effects of long fibers (>5 micrometers in length) vs. short fibers (<5
micrometers in length) currently is a topic of debate. So far, nothing is
known about the importance of fiber size in bronchial tumor production.16 The
primary research relating fiber size to carcinogenic potency applies only to
pleura! m.esothelioma and involves direct injection or implantation of fibers
into the pleura of rats. Some evidence suggests that fibers may have to be
2.10 micrometers in length and <1 micrometer in diameter to produce
mesothelioma.1^ pott (1978), however, states that fibers as short as 3
micrometers in length have carcinogenic potency.-1 Selikoff believes that
fibers less than 3 micrometers in length can produce tumors. Gross (1974)
disagrees with his colleagues and believes that fibers <5 micrometers in
length are devoid of carcinogenic potency.22 stanton and Layard (1977)
investigated the carcinogenicities of 37 different dimensional distributions
of 7 fibrous materials and attained optimum correlation with fibers that
measured <0.25 micrometer in diameter and >8 micrometers in length.23 jhe
authors did not state that fiber sizes outside this optimal range were devoid
of carcinogenic potency.
Presently, there is no firm conclusion concerning relative activities of
short and long fibers. It cannot be said confidently that fibrogenicity drops
to negligible proportions at 5 micrometers or 1 micrometer.24 Pott (1978)
states that even if the carcinogenic potential of a relatively short fiber is
weak, many short fibers may induce a tumor as easily as a few large fibers.
7-5
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The author further states that special problems arise in calculating
carcinogenic potency when bundles of asbestos fibers are encountered. The
possibility of an asbestos fiber bundle splitting when inhaled easily can
increase carcinogenic potency.
7.5.2 Fiber Type
Human occupational exposures to all cominercial asbestos fiber types, both
individually and in various combinations, have been associated with high rates
of asbestosis, lung cancer, and mesothelioma. Presently available information
indicates that the incidence of lung cancer does not depend on the fiber type
but mainly on the dose level. The incidence of mesothelioma appears to be
linked to the type of asbestos.5 There is general agreement that risk of
mesothelioma is fiber related in the following order: crocidolite > amosite >
chrysotile > anthophyllite. The magnitude of the difference between, for
example, crocidolite and chrysotile is not well understood. Timbrell (1973)
states that chrysotile fibers normally are not observed near the pleura
because of their curved shape; however, short chrysotile fibers may behave
like crocidolite and penetrate into deeper regions of the respiratory
system.^5
7.6 SUMMARY OF HEALTH EFFECTS
Asbestos inhalation is known to cause asbestosis, lung cancer, and
mesothelioma in humans. Current knowledge of carcinogenic effects of asbestos
is almost entirely derived from occupational studies. Recent studies of
chrysotile workers that relied on older methods (i.e., impingers) of
estimating dust exposure support the linear dose-response hypothesis for lung
cancer among most exposure groups. The most recent study of chrysotile
workers (Dement et al., 1980) estimated exposure to airborne asbestos fiber
concentrations using phase contrast microscopy and indicated that there is no
threshold to the linear relationship for lung cancer and nonmalignant
respiratory diseases. Evidence of asbestos-related disease in members of
asbestos-worker households and in persons living near asbestos-contaminated
areas adds support to the no-threshold, linear dose-response hypothesis.
Smoking habits and age are two important cofactors associated with
increased risk of asbestos-related diseases. Currently, researchers have
reached no consensus concerning relative carcinogenic potency of short vs.
7-6
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long fibers. The varying intensity and type of exposure, the problem of
exposure estimation, and the influence of cofactors make it extremely
difficult to specify safe exposure levels for the general public.
Consequently, EPA recommends that public exposure to airborne asbestos be
reduced to the greatest extent practical.
7.7 REFERENCES
'-1. National Institute for Occupational Safety and Health (NIOSH), U.S.
Department of Health, Education, and Welfare. Revised Recommended
Asbestos Standard. Washington, D.C. DHEW (NIOSH) Publication Number
77-169. December 1976. p. 53-57.
2. McDonald, J. C., and F. D. Kiddell. Mortality in Canadian Miners and
Millers Exposed to Chrysotile. Annals of the New York Academy of
Science. 330:1-9. December 14, 1979.
3. McDonald, J..C., et al. Dust Exposure and Mortality in Chrysotile
Mining. British Journal of Industrial Medicine. _37_:ll-24. 1980.
4. Henderson, V., and P. E. Enter!ine. Asbestos Exposure: Factors
Associated With Excess Cancer and Respi-ratory Disease Mortality. Annals
of the New York Academy Sciences. _330_: 117-125. December 14, 1979.
5. Dement, J. M., R. L. Harris, M. J. Symons, and C. Shy. Estimates of
Dose-Response For Respiratory Cancer Among Chrysotile Asbestos Textile
Workers. (Presented at the Fifth International Symposium on Inhalable
Particles and Vapors. Cardiff, Wales. September 1980.) p. 10.4-1
to 10.4-23.
6. Zielhuis, R. L. Public Health Risks of Exposure to Asbestos. Report of
a Working Group of Experts Prepared for the Commission of the European
Communities. Directorate-General for Social Affairs, Health and Safety
Directorate. Luxembourg, Pergamon Press. 1977. 143 p.
7. Robinson, C., et al. Mortality Patterns, 1940-1975, Among Workers
Employed in an Asbestos Textile, Friction, and Packing Products
Manufacturing Facility. In: Dust and Diseases, Lemen, R. A., and
Dement, J. M. (eds.) Park Forest South, Pathatox Publishers, Inc. 1979.
p. 131-143.
7-7
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8. Becklake, M. R. Asbestos Related Diseases of the Lung and Other Organs:
Their Epidemiology and Implications for Clinical Practices. American
Review of Respiratory Disease. 114:210. 1976.
9. Wagner, I. C., C. A. Sleggs', and P. Marchand. Diffuse Pleura!
Mesothel ioma and Asbestos Exposure in North Western Cape Province.
British Journal of Industrial Medicine (London). J7:260-271. 1960.
10. Newhouse, M. L., and H. Thompson. Mesothelioma of Pleura and Peritoneum
Following Exposure to Asbestos in the London Area. British Journal of
Industrial Medicine (London). _22_:261-269. 1965.
11. Borow, M. A., et al. Mesothelioma Following Exposure to Asbestos: A
Review of 72 Cases. Chest. 6>4_:641-646. 1973.
12. Anderson, H. R., et al. Household Contact Asbestos Neoplastic Risk.
Annals of the New York Academy of Science. ^71^:311-323. May 23, 1976.
13. Vianna, N. J., and A. K. Polan. Non-occupational Exposure to Asbestos
and Malignant Mesothel iomas in Females. The Lancet. JL_:1061. May 20,
1978.
14. Baris, Y. I. Pleural Mesotheliomas and Asbestos Pleurisies Due to
Environmental Asbestos Exposure in Turkey: An Analysis of 120 Cases.
Hacettepe Bulletin of Medicine. _8(4):165-185. December 1975.
15. Yazialoglu, S. Pleural Calcification Associated with Exposure to
Chrysotile Asbestos in Southeast Turkey. Chest. K>.:43-47. July 1976.
16. Selikoff, I. J., et al. Mortality Effects of Cigarette Smoking Among
Amosite Factory Workers. Journal of National Cancer Institute.
65_(3): 507-513. 1980.
17. Gil son, J. C. Asbestos Cancers as an Example of the Problem of
Comparative Risk. INSERM. _55_: 107-166. 1976.
18. Kotin, P- Briefing Before the Consumer Product Safety Commission-
Federal Register. 22 FR 38786. July 29, 1977.
7-8
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19. Wassermann, M., et al. Mesothelioma in Children. (Presented at the
Symposium on the Biological Effects of Mineral Fibers. Lyon, France.
September 25-27, 1979.)
20. Doll, R. Susceptibility to Carcinogenicities at Different Ages. Geron
Clin. .4:211-221. 1962.
21. Cole, P. Cancer and Occupation. Cancer. _39_: 1788-1791. 1977.
22. Pott, F. Some Aspects of the Dosimetry of the Carcinogenic Potency of
Asbestos and Other Fibrous Dust. Staub-Reinhalt Luft. _12:486-490.
December 1978.
23. Gross, P. Is Short-Fibered Asbestos Dust a Biological Hazard? Archives
of Environmental Health. _29:115-117. August 1974.
24. Stanton, M., and M. Layard. The Carcinogenicity of Fibrous Minerals.
National Cancer Institute. Bethesda, Maryland. Presented at Proceedings
of the Workshop on Asbestos: Definitions and Measurement Methods.
Gaithersburg, Maryland. 1977.) p. 143-151.
25. Selikoff, I., and D. Lee. Asbestos and Disease. Academic Press. 1978.
p. 428.
26. Timbrel!, V. Physical Factors as Etiological Mechanisms. Biological
Effects of Asbestos. IARC. Lyon, France, p. 295. 1975.
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S. ENFORCEMENT AND COMPLIANCE EXPERIENCE
8.1 JURISDICTION: STATE VS. FEDERAL
Section 116 of the Clean Air Act addresses the retention of authority by
States or political subdivisions within States. Such political entities may
regulate air pollution by limiting emissions from sources or by requiring use
of control or abatement methods. The only stipulation is that for sources
regulated under Sections 111 or 112 (New Source Performance Standards [NSPS]
and National Emission Standards for Hazardous Air Pollutants [NESHAPs],
respectively) of the Clean Air Act, States or their political subdivisions
cannot adopt standards less stringent than those under Sections 111 or 112.
States that have been delegated partial or total NESHAP authority are listed
in Table 8-1. Most States with NESHAP authority have simply adopted the
Federal standard by reference. Some States; e.g., Illinois, New Jersey, and
New York, have developed and enforced their own regulations, which differ from
the NESHAP. In States that have no regulations specifically governing
asbestos, the Federal NESHAP is applicable and is enforced by EPA's regional
enforcement branches.
8.2 INDUSTRY CONCERNS
In general, industry personnel did not object strongly to the present
asbestos NESHAP. In a letter to the President's Task Force on Regulatory
Relief, the Asbestos Information Association/North America (AIA) discussed
several pending regulatory actions it considered likely to affect the asbestos
industry adversely.2 The existing asbestos NESHAP was described as
"... workable for industry and effective in reducing asbestos
exposures ..."
The most frequently negative comment from industry personnel was that the
NESHAP was difficult to understand and often resulted in confusion in standard
compliance. For example, in complying with the "no visible emission"
limitation, some plant personnel were uncertain if they must also comply with
8-1
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TABLE 8-1. STATES WITH NESHAP AUTHORITY1
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Del aware
Florida
Georgia
Hawaii
Idaho
111 inois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Mary! and
Massachusetts
Michigan
Status of NESHAP delegation
Yes
No
__a
No
__a
Yes
Yes
Yes
No
Yes
No
No
No
Yes
No
No
Yes
No
Yes
No
Yes
Yes
(Continued)
8-2
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TABLE 8-1. STATES WITH NESHAP AUTHORITY1 (Continued)
State
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South Carolina
South Dakota
Tennessee
Texas
Status of NESHAP delegation
Yes
No
No
Yes
No
a
Yes
Yes
No
Yes
Yes
Yes
No
No
Yes
Yes
No
Yes
No
Yes
Yes
(Continued)
8-3
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TABLE 8-1. STATES WITH NESHAP AUTHORITY1 (Continued)
State
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
Wyoming
Status of NESHAP delegation
No
Yes
Yes
Yes
No
Yes
No
aMany States are divided into air quality control districts for NESHAP
enforcement and report directly to the Federal EPA. Some State districts,
counties, and cites have developed and enforce their own regulations.
California--Bay Area, Del Norte, . . ., and S. Coast District.
Nevada--Clark and Washoe districts.
Arizona--Pima County and Maricopa County.
8-4
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control equipment specifications in Section 61.23. During one plant visit,
plant personnel suggested that the standard's control equipment specifications
in Section 61.23 might be more appropriately designated guidelines instead of
regulations to allow individual plants opportunity to design and operate
control systems that better meet their specific needs.3 Generally, industry
personnel considered the "no visible emission" limitation adequate.
8.3 REGIONAL EPA CONCERNS
Major concerns expressed by regional enforcement personnel are described
below.
8.3.1 Work Practice Enforcement
Many Federal enforcement personnel believe they cannot enforce the work
practice and nonemission provisions of the standard as a result of the U.S.
Supreme Court ruling in the Adamo case. Therefore, enforcement activities are
directed primarily at the "no visible emission" limitation.
8.3.2 Regulatory Language
Regional enforcement personnel have commented that the standard is
difficult to understand, adding uncertainty to already uncertain enforcement
activities. The difficulty in interpretation is caused partially by unclear
terms. For example, the definitions of "manufacturing," "fabricating," and
"commercial asbestos" are not clear and have resulted in uncertainty regarding
applicability of the standard.
8.3.3 Notification
Regional EPA personnel have identified several problems with notification
requirements for demolition and renovation. Some contractors and building
inspectors responsible for permitting demolition jobs appear to be unaware of
reporting requirements and do not inquire of the presence of asbestos in a
building. Enforcement personnel believe a substantial amount of demolition
occurs when the contractor at least suspects that asbestos is present and does
not make the proper notification. Owners of buildings to be demolished also
seem to be unaware of or ignore the possible presence of asbestos. When
received, notifications often lack information, arrive late, or arrive after
the job is completed. EPA enforcement officials state that enforcement is
difficult because of personnel shortages. If notifications were received for
8-5
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all demolition and renovation jobs, it would be extremely difficult, if not
impossible, to inspect each site.
8.3.4 Emission Limitation
Although "no visible emissions" is considered a fairly stringent
standard, a quantitative limit would be easier to enforce because it would
eliminate subjectivity.
8.3.5 Unregulated Source
The only potential emission source enforcement officials identified as
not being covered by the asbestos NESHAP was the application of encapsulants
over asbestos-containing materials. The pressure with which encapsulants are
applied causes asbestos fiber release.
8.4 APPLICABILITY DETERMINATIONS
Since promulgation of the asbestos NESHAP, numerous inquiries have been
made concerning the standard's applicability to various asbestos uses. Table
8-2 presents examples of the type of inquiries directed to the Division of
Stationary Source Enforcement (DSSE).
8.5 UNREGULATED EMISSION SOURCES
Several potential sources of asbestos emissions are unregulated by the
current standard but were considered during promulgation of the standard and
its amendments. In addition, two potential sources not considered
previously~spray-on encapsulants and drilling muds—have now been identified.
These unregulated sources are discussed below.
8.5.1 Onsite Fabrication
Asbestos-containing building materials, such as asbestos/cement (A/C)
pipe and A/C sheet, may undergo cutting, drilling, or grinding at the
installation site. Such onsite fabrication previously was considered to occur
infrequently and was not considered a major emission source. More recent
information indicates that this infrequency continues.^
8.5.2 Demolition
Where less than 80 meters (260 feet) of pipe or less than 15 meters^ (160
feet^) of surface is covered with asbestos or where apartments with four or
fewer dwelling units are to be demolished, the NESHAP does not apply. These
8-6
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TABLE 8-2. ASBESTOS NESIIAP DETERMINATIONS
Question
Determination
Discussion
CO
Is the cutting of asbestos paper
covered?
A manufacturer has two plants.
Plant A produces asbestos paper
shipped to Plant B. Plant B
makes roofing tile from the
asbestos paper and treats it
with an asphalt mix. Is Plant B
covered by the standard?
Are visible emissions from
asbestos block curing ovens
subject to NESHAP regulations?
What is an acceptable method for
identifying asbestos samples found
in demolition/renovation
inspections?
Can the fencing requirement in
Section 61.25(c) be satisfied by
placing a fence along the property
line of a plant containing an
asbestos disposal site rather than
around the perimeter of the disposal
site?
Yes
No
No
No
Microscopy
Yes
Asbestos paper cutting is covered if done prior to
initial marketing.
Asbestos paper cutting is not covered if it has been
marketed initially. This would be fabrication and
not manufacturing.
The standard covers manufacturing of asbestos paper
paper but not fabrication of asbestos paper
products.
Visible emissions from these sources are caused by
resins (hydrocarbons) and not by asbestos.
EPA has relied on polarized microscopy in most
enforcement cases. This method is used to identify
hard samples of asbestos found at demolition,
renovation, and waste disposal sites.
This question was resolved in 40 FR 48294, October
14, 1975, in response to a comment on amendments
proposed on October 25, 1974. A fence that
surrounds a plant property and adequately deters
public access may substitute for a fence around
the perimeter of a disposal site located within the
property fence.
(Continued)
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TABLE 8-2. ASBESTOS NESHAP DETERMINATIONS (Continued)
Question
Determination
Discussion
oo
i
co
Does the 1-percent limit on asbestos
content of spray-on materials apply
to naturally occurring and
commercially-added asbestos?
Is a wallboard manufacturing
facility that uses tailings fines
from an asbestos mine as filler
material subject to Section
61.22(c)7 Is it subject to any
other section of the asbestos
regulations?
Yes
No
In reference to the asbestos
regulations, are inactive waste
disposal sites prevented or
restricted from future use as
commercial or residential sites?
Conditional
The 1-percent limit on spraying of asbetos-
containing materials in Section 61.22(e) does not
specify commercial asbestos. Therefore, the
limitation is applicable to naturally occurring and
commercial asbestos.
Section 61.22(c) applies to manufacturing operations
that use commercial asbestos. Since tailings fines
do not fall'into the "commercial asbestos" category,
as defined in Section 61.21(h), the operation is not
subject to Section 61.22(c). Since the source of
the tailings fines is a mine, use of the tailings in
the wallboard manufacturing process is not covered
by any section under Subpart B. However, if the
source of the tailings fines was an asbestos mil 1 ,
any operations involving collection, processing,
packaging, transport, or deposition of the tailings
fines would be subject to the requirements.
Inactive disposal sites may be used for commercial
or residential development provided asbestos
exposure is avoided in accordance with Section
61.22(e).
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exemptions were made because such situations did not constitute major emission
sources. Nothing was identified during the Phase I study to alter these
exemptions.
8.5.3 Contaminant Sources
Various other minerals, such as iron ore and serpentine rock, may contain
asbestos. The industries that process these minerals are not regulated by the
asbestos NESHAP. EPA previously has considered regulating production and use
of these contaminant sources. For iron ore, EPA concluded that the primary
emission sources are now being controlled as a result of State and Federal
litigation. For crushed rock from serpentine deposits used to maintain
unpaved roads, EPA concluded that local, State and Federal authorities
responsible for limited areas of concern were best able to assess and control
use of the stone. EPA published "Assessment and Control of Chrysotile
Asbestos Emissions from Unpaved Roads" to provide guidance to the appropriate
authorities.6
8.5.4 Asbestos Mining
The Bureau of Mines regulated asbestos exposures from mining operations
at the time of the April 6, 1973, promulgation. Now the Mine Safety and
Health Administration (M-SHA) has the safety and health responsibilities that
once belonged to the Bureau of Mines. MSHA regulates airborne asbestos
concentration and requires use of respirators only after available
environmental control measures have been used first. The number of U.S. mines
has declined from the number that existed during the early 1970s and domestic
production has declined.
8.5.5 Fabricators
The NESHAP regulates fabricators of A/C building products, friction
products, and A/C or asbestos-silicate board for ventilation hoods, ovens,
electrical panels, laboratory furniture, bulkheads, partitions and ceilings
for marine construction, and flow control devices for the molten metal
industry. Other fabricators or secondary processors were not considered
major emission sources. No increase in emissions from fabrication or
secondary processing was found, and some asbestos uses have significantly
declined because of the availability of asbestos substitutes, increasing
concerns about health risks, increasing regulations, and present day economy.
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8.5.6 Encapsulants
Use of encapsulants or sealants over sprayed asbestos surfaces is a
potential emission source not previously considered. Sealing of sprayed
asbestos surfaces involves application of material that will envelop or coat
the fiber matrix, eliminate fallout, and protect against contact damage.
Sealants usually are applied to asbestos surfaces by spraying and consist of
polymers with an agent added to enhance penetration into the fiber matrix.
Currently available sealants include water-based latex polymers, water-soluble
epoxy resins, and organic-solvent-based polymers of various types.
Application of a sealant to friable asbestos by spraying will disseminate
small fibers by contact. A sealant should be applied with as much caution and
at as low a nozzle pressure as possible to reduce contact disturbance.?
8.5.7 Drilling Muds
A potential emission source that has not been considered for regulation
is asbestos use in drilling muds. The following description is taken from a
1976 report.8
Drilling fluids (muds) are essential for drilling oil and gas wells.
Asbestos use in drilling muds is well established-and can lower the cost of
drilling and completing wells significantly. Drilling muds are pumped down
through the drill pipe and up the annul us between the drill pipe and the well
bore wall. When the drilling muds arrive on the surface, they flow over a
shaker screen to remove the drill bit cuttings and into a mud pit. The fluid
is recirculated through the hole. Materials needed to maintain properties of
the drilling fluid are added in the surface pit.
The main function of the drilling mud is to remove drill cuttings from
the hole and to contain formation pressures in the hole. The mud also removes
heat from the drilling action, acts as a lubricant, and prevents excessive
hole erosion. The drilling mud must remain fluid enough to be pumped with
minimum pressures. The mud must not be lost to the formation yet must
overcome formation pressures to prevent ingress of oil, gas, or water.
Asbestos is added to the drilling mud to improve its carrying capacity
without appreciably increasing viscosity. Other methods of improving carrying
capacity markedly increase viscosity, which increases pump pressures, reduces
power available at the bit, and slows drilling. Slow drilling rates increase
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ciriTHng costs. Asbestos is used in concentrations of from 0.9 to 2.3
kilograms (2 to 5 pounds) per barrel (1 barrel equals 42 gallons) of mud.
Asbestos is added to the drilling fluid through a mud hopper or large
funnel with the potential for fibers being released into the atmosphere.
Initially, a volume of mud of from 150 to 200 barrels is prepared. As
drilling progresses, additions are made to the system to maintain and to
accommodate the volume of the hole being drilled. Typically, these conditions
occur only once during an 8-hour shift. The asbestos added is minimal — rarely
exceeding 225 kilograms (500 pounds) at a time.
Over 30,000 wells are drilled per year in the United States, and
approximately 1,500 drilling rigs are used. Frequent movement from site to
site makes fixed control equipment for asbestos fiber exposure infeasible. A
normal drilling crew consists of four men working an 8-hour shift; that is,
three 8-hour crews per day. Drilling sites may be miles from any population
center and are subject to extreme climatic conditions (e.g., the north coast
of Alaska to the Gulf of Mexico).
According to the AIA, the quantity of asbestos fiber annually consumed
for drilling fluids is approximately 9,100 metric tons (10,000 short tons).
The shorter grades of chrysotile fibers are normally used, and pelletized
fiber and loose fiber can be used.9
8.6 REFERENCES
1. Asbestos Information Association. Asbestos State and Federal
Regulations, Annex A. Arlington, Virginia. February 1978.
2. Letter and attachments from Dougherty, T. A., Asbestos Information
Association/North America, to the Honorable George Bush, Vice President,
United States. April 30, 1981. 11 p. Asbestos industry issues for the
Task Force on Regulatory Relief.
3. Laney, M. Trip Report—Initial Plant Visit, Bendix Corporation, May 14,
1981. Research Triangle Institute. Research Triangle Park, North
Carolina. May 21, 1981. 5 p.
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4. Wright, M. D., et a"!. Asbestos Dust, Technological Feasibility Impact
Analysis of the Proposed Federal Occupational Standard. Part I:
Technological Feasibility Assessment and Economic Impact Analysis.
Research Triangle Institute. Research Triangle Park, North Carolina.
(Prepared for the Occupational Safety and Health Administration.
Washington, D.C.) NTIS No. RTI/1370/02-01-F. September 1973.
p. 111-20 to 111-34.
5. U.S. Environmental Protection Agency. National Emission Standards for
Hazardous Air Pollutants, Development of Asbestos Standard for the
Production and Use of Crushed Stone: Advanced Notice of Proposed
Rulemaking. Federal Register. _42_(217) :58543. November 10, 1977.
6. Serra, R. K., and M. A. Connor. Assessment and Control of Chrysotile
Asbestos Emissions from Unpaved Roads. Midwest Research Institute.
Raleigh, North Carolina. (Prepared for the Office of Air Quality
Planning and Standards, U.S. Environmental Protection Agency. Research
Triangle Park, North Carolina.) EPA-450/3-81-006. May 1981. 105 p.
7. Sawyer, R. N., and C. M. Spooner. Yale University and GCA Corporation.
Sprayed Asbestos-Containing Materials in Buildings: A Guidance Document.
(Prepared for Office of Air Quality Planning and Standards, U.S.
Environmental Protection Agency. Research Triangle Park, North
Carolina.) EPA-450/2-78-014. March 1978. 133 p.
8. Daly, A. R. Technological Feasibility and Economic Impact of OSHA
Proposed Revision to the Asbestos Standard. Westchester, Pennsylvania.
Roy F- Weston, Environmental Consultants-Designers. (Prepared for the
Asbestos Information Association/North America. Washington, D.C.)
March 1976. 189 p.
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Meylan, W. S., P- H. Howard, S. S. Lande, and A. Hanchett. Chemical
Market Input/Output Analysis of Asbestos to Assess Sources of
Environmental Contamination. Syracuse Research Corporation. Syracuse,
New York. (Prepared for the Office of Toxic Substances, U.S.
Environmental Protection Agency. Washington, D.C.) EPA-560/6-78-005.
August 1978. 323 p.
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9. OTHER FEDERAL REGULATORY ACTIVITIES
Asbestos is probably one of the most regulated substances in this
country. Numerous standards address asbestos directly; e.g., the U.S.
Environmental Protection Agency's (EPA) National Emission Standard for
Hazardous Air Pollutants (NESHAP), the Occupational Safety and Health
Administration's (OSHA) work place standards for asbestos, and the Mine Safety
and Health Administration's (MSHA) health and safety standards for workers.
Several generic standards also address hazardous substances and eventually may
result in asbestos regulation. In addition, several proposed or outstanding
regulations are aimed at regulating different aspects of asbestos use.
The objective of this chapter is to identify existing and proposed
asbestos-specific and generic regulations. The exact manner in which all
current and proposed regulations will interface with the revised asbestos
NESHAP will depend substantially on details of the revision. As part of the
Phase II revision process, all of the various standards will be evaluated to
determine how they should interface with the NESHAP revision.
The discussion of regulations is segregated by regulatory agency. A
brief statement summarizes major points of each standard, and standards are
designated proposals or existing regulations.
9.1 ENVIRONMENTAL PROTECTION AGENCY
9.1.1 Clean Air Act
The purpose of the Clean Air Act is to achieve and maintain air quality
to protect the public health and welfare. Primary and secondary ambient air
quality standards were established under the Act, and States were required to
prepare implementation plans to attain and maintain those standards. EPA must
also establish performance standards for new and modified stationary sources
and standards for hazardous air pollutants (e.g., asbestos). The Office of
Air Quality Planning and Standards (OAQPS) has authority under the Clean Air
Act to research and develop air quality standards.
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9.1.1.1 National Standards for Hazardous Air Pollutants; Policy and
procedures for Identifying, Assessing, and Regulating Airborne
Substances Posing a Risk of Cancer; Proposed Rulemaking 44 FR
58642; October 10. 1979
Proposed pursuant to the Clean Air Act, the carcinogen rule considers
policies and procedures to determine carcinogenicity and risks for a specific
pollutant, establish priorities for regulatory action, specify degree of
control, and provide public input to the decisionmaking process.
9.1.2 Resource Conservation and Recovery Act
The objectives of the Resource Conservation and Recovery Act (RCRA) of
1976 (PL 94-580) are to promote protection of health and the environment and
to conserve valuable materials and energy through regulation of solid waste
disposal, including hazardous waste disposal. RCRA regulates waste from point
of generation, through transporation, storage, and disposal. Records are kept
of the quantity, composition, origin, routing, and destination of waste from
"cradle-to-grave." Authority for administering RCRA lies with the Office of
Solid Waste.
9.1.3 Toxic Substances Control Act
The purpose of the Toxic Substances Control Act (TSCA) of 1976 (PL 94-
469) is the regulation of chemical substances that present a hazard to health
or the environment. The Act has a broad purview and deals with toxic
substances throughout their life cycle, including manufacturing, distribution,
use, and disposal. Authority for administering TSCA lies with the Office of
Pesticides and Toxic Substances. Rules and proposals that affect asbestos are
listed below.
9.1.3.1 Chemical Imports and Exports; Notification of Exports; Final
Rule 40 CFR 707, Subpart D
Section 12(b) of TSCA requires anyone who exports to another country a
chemical substance to notify EPA of such plans if the substance meets one of
several criteria. One of the criteria, which would require asbestos to comply
with the exporting rule, is that a rule has been promulgated or proposed, under
Section 6 of TSCA with respect to the chemical substance. Section 6 of TSCA
defines regulatory alternatives to be used to reduce health risks. A proposal
9-2
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under Section 6 has been issued for asbestos; therefore, asbestos is subject
to EPA's export rule.
9.1.3.2 Commercial and Industrial Use of Asbestos Fibers; Advance Notice
of Proposed Rulemaking; 44 FR 60061 (October 17, 1979)
Pursuant to Section 6 of TSCA, EPA is considering various approaches to
control risks from asbestos, including banning certain products and limiting
asbestos imported and produced annually in the United States.
9.1.3.3 Asbestos; Reporting and Recordkeeping Requirements, Proposed
Rule; 46 FR 8200 (January 26, 1981)
Pursuant to Section 8(a) of TSCA, EPA is proposing that manufacturers,
importers, and processors of asbestos report certain information to EPA to
help regulate asbestos. Information to be reported includes quantities of
asbestos used, employee exposure and monitoring data, and waste disposal and
pollution control information.
9.1.3.4 Asbestos-Containing Materials in School Buildings; Advance
Notice of Proposed Rulemaking; 44 FR 54676 (September 20, 1979)
Pursuant to Section 6 of TSCA, EPA announced plans to require all public
and private schools to identify asbestos-containing products in schools and
then to take corrective steps to reduce exposures.-
9.1.3.5 Friable Asbestos-Containing Materials in Schools; Proposed
Identification and Notification, Proposed Rule; 45 FR 61966
(September 17, 1980)
Pursuant to Section 6 of TSCA, EPA proposed the first phase in
identifying asbestos in schools, including bulk sampling and analysis,
recordkeeping, and notifying affected persons.
9.1.4 Clean Water Act
The Clean Water Act of 1977 (PL 95-217) comprehensively amends the
Federal Water Pollution Control Act as amended in 1972. The Clean Water Act
significantly changes requirements for control of industrial discharges,
construction of municipal sewage treatment plants, management of nonpoint
sources, protection of wetlands, and other related concerns. Pursuant to
Section 304(a) of the Clean Water Act, EPA adopted water quality criteria for
asbestos (44 FR 56628, October 1, 1979). Prior to the Clean Water Act of
1977, effluent limitation guidelines were established (39 FR 7526, February
9-3
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26, 1974) for existing sources and standards of performance and pretreatnent
standards for new sources within the asbestos/cement (A/C) pips, A/C sheet,
asbestos paper (starch binder) and (elastometric binder), asbestos millboard,
asbestos roofing products, and asbestos floor tile subcategories of the
asbestos manufacturing category of point sources were set. Final effluent
guidelines were established (40 FR 1847, January 9, 1973) for additional
related subcategories within the asbestos manufacturing category.
9.2 OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION
The current OSHA standard, 29 CFR 1910.1001, is applicable to both
general industry and construction. The standard limits employee exposure to 2
fibers per cubic centimeter over an 8-hour period or to a ceiling
concentration of 10 fibers per cubic centimeter. The standard specifies
compliance methods, use of personal protective equipment, measurement methods,
use of signs, housekeeping and recordkeeping practices, and use of employee
medical examinations. OSHA proposed in 40 FR 47652, October 9, 1975, to lower
allowable exposure limits from 2 to 0.5 fiber per cubic centimeter. However,
it is not clear that they are now actively pursuing promulgation of this more
stringent standard.
9.3 CONSUMER PRODUCT SAFETY COMMISSION
The Consumer Product Safety Commission (CPSC) banned asbestos-containing
consumer patching compounds and artificial emberizing materials on December
15, 1977, (42 FR 63354). On October 17, 1979, in 44 FR 60057, CPSC issued an
Advance Notice of Proposed Rulemaking soliciting information on the use of
asbestos in consumer products. This information may be used to regulate
asbestos further in consumer products.
9.4 FOOD AND DRUG ADMINISTRATION
Pursuant to the Federal Food, Drug, and Cosmetic Act, the Food and Drug
Administration (FDA) banned asbestos-containing garments for general use in
households from interstate commerce in 37 FR 14872, July 26, 1972. On March
14, 1975, in 40 FR 11865, the FDA required that filters used in manufacturing,
processing, or packaging of drugs used for human parenteral injections cannot
release fibers into such products. The Act established other manufacturing
practices to limit asbestiform particles in drugs for parenteral injection.
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On January 22, 1976, the FDA revoked the regulation (41 FR 3236) allowing the
use of the electrolytic diaphragm process for salt because the process does
not remove asbestos as well as conventional methods.
9.5 DEPARTMENT OF TRANSPORTATION
Pursuant to the Hazardous Materials Transportation Act, the Department of
Transportation (DOT) proposed rules in 43 FR 8562 (March 2, 1978) for
regulation of transporting asbestos. The rules specify containment measures
for asbestos and asbestos-containing materials but exclude asbestos that is
immersed or fixed in a binder material and that is in a manufactured product.
9.6 MINE SAFETY AND HEALTH ADMINISTRATION
The Mine Safety and Health Administration (MSHA) regulations provide for
employee protection and are similar to the OSHA standards. In 41 FR 10223
(March 10, 1976), MSHA established that mine workers cannot be exposed to
greater than 2 fibers per cubic centimeter over an 8-hour period, nor could
they be exposed to a ceiling concentration greater than 10 fibers per cubic
centimeter for more than 1. hour each 8-hour day.
9.7 OTHER FEDERAL AGENCIES
Pursuant to the Asbestos School Hazard Detection and Control Act of 1980
(PL 96-270), on September 17, 1980, the Department of Education issued in
45 FR 61950 a Notice of Proposed Rulemaking, entitled "Asbestos Detection and
Control; Local Educational Agencies; Asbestos Detection and State Plan: State
Educational Agencies." The proposal establishes procedures to make Federal
grants available to local and State educational agencies to help them identify
and correct asbestos hazards in school buildings. The National Institute of
Environmental Health Sciences (NIEHS), the National Institute for Occupational
Safety and Health (NIOSH), the National Cancer Institute (NCI), and the Public
Health Service are other Federal agencies that have interests related to
regulation of asbestos.
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