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(continued)
(B) The employer shall provide to the Chief and the Director, upon request, all information and training materials relating to the employee information and training program.
(C) The employer shall inform all employees concerning the availability of self-help smoking cessation program material. Upon employee request, the employer shall distribute such material, consisting of NIH Publication No, 89- 1647, or equivalent self-help material, which is approved or published by a public health organization listed in Appendix J to this section.
(l) Housekeeping
(1) Vacuuming. Where vacuuming methods are selected, HEPA filtered vacuuming equipment must be used. The equipment shall be used and emptied in a manner that minimizes the reentry of asbestos into the workplace.
(2) Waste disposal. Asbestos waste, scrap, debris, bags, containers, equipment, and contaminated clothing consigned for disposal shall be collected and disposed of in sealed, labeled, impermeable bags or other closed, labeled, impermeable containers except in roofing operations, where the procedures specified in subsection (g)(8)(B) of this section apply.
(3) Care of asbestos-containing flooring/deck material.
(A) All vinyl and asphalt flooring/deck material shall be maintained in accordance with this subsection unless the building/facility owner demonstrates, pursuant to subsection (g)(8)(A)9. of this section, that the flooring/deck does not contain asbestos.
(B) Sanding of flooring/deck material is prohibited.
(C) Stripping of finishes shall be conducted using low abrasion pads at speeds lower than 300 rpm and wet methods.

(D) Burnishing or dry buffing may be performed only on flooring/ deck which has sufficient finish so that the pad cannot contact the flooring/deck material.
(4) Waste and debris and accompanying dust in an area containing accessible thermal system insulation or surfacing ACM/PACM or visibly deteriorated ACM:
(A) shall not be dusted or swept dry, or vacuumed without using a HEPA filter;
(B) shall be promptly cleaned up and disposed of in leak tight containers.
(m) Medical surveillance
(1) General
(A) Employees covered.
1. The employer shall institute a medical surveillance program for all employees who, for a combined total of 30 or more days per year, are engaged in Class I, II and III work or are exposed at or above the permissible limit. For purposes of this paragraph, any day in which a worker engages in Class II or Class III operations or a combination thereof on intact material for one hour or less (taking into account the entire time spent on the removal operation, including cleanup) and, while doing so, adheres fully to the work practices specified in this standard, shall not be counted.
2. For employees otherwise required by this standard to wear a negative pressure respirator, employers shall ensure employees are physically able to perform the work and use the equipment. This determination shall be made under the supervision of a physician.
(B) Examination.
1. The employer shall ensure that all medical examinations and procedures are performed by or under the supervision of a licensed physician, and are provided at no cost to the employee and at a reasonable time and place.
2. Persons other than such licensed physicians who administer the pulmonary function testing required by this section shall complete a training course in spirometry sponsored by an appropriate academic or professional institution.
(2) Medical examinations and consultations.

(A) Frequency. The employer shall make available medical examinations and consultations to each employee covered under subsection (m)(1)(A) of this section on the following schedules:
1. Prior to assignment of the employee to an area where negative- pressure respirators are worn;
2. When the employee is assigned to an area where exposure to asbestos may be at or above the permissible exposure limit for 30 or more days per year, or engage in Class I, II, or III work for a combined total of 30 or more days per year, a medical examination must be given within 10 working days following the thirtieth day of exposure;
3. And at least annually thereafter.
4. If the examining physician determines that any of the examinations should be provided more frequently than specified, the employer shall provide such examinations to affected employees at the frequencies specified by the physician.
5. Within 30 calendar days before or after termination of employment.
6. Exception: No medical examination is required of any employee if adequate records show that the employee has been examined in accordance with this subsection within the past 1-year period.
(B) Content. Medical examinations made available pursuant to subsections (m)(2)(A)l. through (m)(2)(A)3. of this section shall include:
1. A medical and work history with special emphasis directed to the pulmonary, cardiovascular, and gastrointestinal systems.
2. On initial examination, the standard questionnaire contained in Part 1 of Appendix D to this section and, on annual examination, the abbreviated standardized questionnaire contained in Part 2 of Appendix D to this section.
3. A physical examination directed to the pulmonary and gastrointestinal systems, including a chest, x-ray to be administered in accordance with Table 2 below, and pulmonary function tests of forced vital capacity (FVC) and forced expiratory volume at one second (FEV(1)). interpretation and classification of chest roentgenogram shall be conducted in accordance with Appendix E to this section.
Table 2 Frequency of Chest X-Rays


YEARS SINCE AGE OF EMPLOYEE
FIRST
EXPOSURE LESS THAN 40 40 AND OLDER
0-10 EVERY 3 YEARS ANNUALLY [FNa1]
10+ ANNUALLY [FNa1] ANNUALLY [FNa1]
[FNa1] Oblique x-rays need only be performed every 3 years.
[FNa1] Oblique x-rays need only be performed every 3 years.


4. Any other examinations or tests deemed necessary by the examining physician.
(3) Information provided to the physician. The employer shall provide the following information to the examining physician:
(A) A copy of this standard and Appendices D, E, and I to this section;
(B) A description of the affected employee's duties as they relate to the employee's exposure;
(C) The employee's representative exposure level or anticipated exposure level;
(D) A description of any personal protective and respiratory equipment used or to be used; and
(E) Information from previous medical examinations of the affected employee that is not otherwise available to the examining physician.
(4) Physician's written opinion.
(A) The employer shall obtain a written opinion from the examining physician. This written opinion shall contain the results of the medical examination and shall include:
1. The physician's opinion as to whether the employee has any detected medical conditions that would place the employee at an increased risk of material health impairment from exposure to asbestos;
2. Any recommended limitations on the employee or on the use of personal protective equipment such as respirators; and
3. A statement that the employee has been informed by the physician of the results of the medical examination and of any medical conditions that may result from asbestos exposure.
4. A statement that the employee has been informed by the physician of the increased risk of lung cancer attributable to the combined effect of smoking and asbestos exposure.
(B) The employer shall instruct the physician not to reveal in the written opinion given to the employer specific findings or diagnoses unrelated to occupational exposure to asbestos.
(C) The employer shall provide a copy of the physician's written opinion to the affected employee within 30 days from its receipt.
(n) Recordkeeping.
(1) Objective data relied on pursuant to subsection (f) of this section.

(A) Where the employer has relied on objective data that demonstrates that products made from or containing asbestos or the activity involving such products or material are not capable of releasing fibers of asbestos in concentrations at or above the permissible exposure limit and/or excursion limit under the expected conditions of processing, use, or handling to satisfy the requirements of subsection (f) of this section, the employer shall establish and maintain an accurate record of objective data reasonably relied upon in support of the exemption.
(B) The record shall include at least the following information:
1. The product qualifying for exemption;
2. The source of the objective data;
3. The testing protocol, results of testing, and/or analysis of the material for the release of asbestos;
4. A description of the operation exempted and how the data support the exemption; and
5. Other data relevant to the operations, materials, processing, or employee exposures covered by the exemption. (C) The employer shall maintain this record for the duration of the employer's reliance upon such objective data.
(2) Exposure measurements.
(A) The employer shall keep an accurate record of all measurements taken to monitor employee exposure to asbestos as prescribed in subsection (f) of this section.
Note: The employer may utilize the services of qualified organizations such as industry trade associations and employee associations to maintain the records required by this section.
(B) This record shall include at least the following information:
1. The date of measurement;
2. The operation involving exposure to asbestos that is being monitored;
3. Sampling and analytical methods used and evidence of their accuracy;
4. Number, duration, and results of samples taken;
5. Type of protective devices worn, if any; and
6. Name, social security number, and exposure of the employees whose exposures are represented.
(C) The employer shall maintain this record for at least thirty (30) years, in accordance with Section 3204 of the General industry Safety Orders.
(3) Medical surveillance.
(A) The employer shall establish and maintain an accurate record for each employee subject to medical surveillance by subsection (m) of this section, in accordance with Section 3204 of the General Industry Safety Orders.
(B) The record shall include at least the following information:
1. The name and social security number of the employee;
2. A copy of the employee's medical examination results, including the medical history, questionnaire responses, results of any tests, and physician's recommendations.
3. Physician's written opinions;
4. Any employee medical complaints related to exposure to asbestos; and
5. A copy of the information provided to the physician as required by subsection (m) of this section.
(C) The employer shall ensure that this record is maintained for the duration of employment plus thirty (30) years, in accordance with Section 3204 of the General Industry Safety Orders.
(4) Training records. The employer shall maintain all employee training records for one (1) year beyond the last date of employment by that employer.
(5) Data to Rebut PACM: Where the building owner and employer have relied on data to demonstrate that PACM is not asbestos-containing, such data shall be maintained for as long as they are relied upon to rebut the presumption.

(6) Records of Required Notification. Where the building/vessel owner has communicated and received information concerning the identity, location and quantity of ACM and PACM, written records of such notifications and their content shall be maintained by the owner for the duration of ownership and shall be transferred to successive owners of such buildings/facilities/vessels.
(7) Availability. (A) The employer, upon written request, shall make all records required to be maintained by this section available to the Chief and the Director for examination and copying.
(B) The employer, upon request, shall make any exposure records required by subsections (f) and (n) of this section available for examination and copying to affected employees, former employees, designated representatives, and the Chief, in accordance with Section 3204 of the General Industry Safety Orders.
(C) The employer, upon request, shall make employee medical records required by subsections (m) and (n) of this section available for examination and copying to the subject employee, anyone having the specific written consent of the subject employee, and the Chief, in accordance with Section 3204 of the General Industry Safety Orders.

(8) Transfer of records.
(A) The employer shall comply with the requirements concerning transfer of records set forth in Section 3204 of the General Industry Safety Orders.
(B) Whenever the employer ceases to do business and there is no successor employer to receive and retain the records for the prescribed period, the employer shall notify the Director at least 90 days prior to disposal and, upon request, transmit them to the Director.
(o) Qualified person.
(1) General. On all shipyard worksites covered by this standard, the employer shall designate a qualified person, having the qualifications and authorities for ensuring worker safety and health required by Sections 1509, 1510, 1512, 1513, 1514, 1523, and 1920 of the Construction Safety Orders.
(2) Required Inspections by the Qualified Person. Section 1509(a) of the Construction Safety Orders which requires health and safety prevention programs to provide for frequent and regular inspections of the job sites, materials, and equipment to be made by qualified persons, is incorporated.
(3) Additional Inspections. In addition, the qualified person shall make frequent and regular inspections of the job sites, in order to perform the duties set out in subsection (o)(3)(A) of this section. For Class I jobs, on-site inspections shall be made at least once during each work shift, and at any time at employee request. For Class II, III, and IV jobs, on-site inspections shall be made at intervals sufficient to assess whether conditions have changed, and at any reasonable time at employee request.
(A) On all worksites where employees are engaged in Class I or II asbestos work, the qualified person designated in accordance with subsection (e)(6) of this section shall perform or supervise the following duties, as applicable:
1. Set up the regulated area, enclosure, or other containment;
2. Ensure (by on-site inspection) the integrity of the enclosure or containment;
3. Set up procedures to, control entry to and exit from the enclosure and/or area;
4. Supervise all employee exposure monitoring required by this section and ensure that it is conducted as required by subsection (f) of this section;
5. Ensure that employees working within the enclosure and/or using glove bags wear respirators and protective clothing as required by subsections (h) and (i) of this section;
6. Ensure through on-site supervision, that employees set up, use, and remove engineering controls, use work practices and personal protective equipment in compliance with all requirements;
7. Ensure that employees use the hygiene facilities and observe the decontamination procedures specified in subsection (j) of this section;
8. Ensure that through on-site inspection, engineering controls are functioning property and employees are using proper work practices; and
9. Ensure that notification requirements in subsection (k) of this section are met.

(4) Training for the competent person;
(A) For Class I and II asbestos work the qualified person shall be trained in all aspects of asbestos removal and handling, including: abatement, installation, removal and handling: the contents of this standard; the identification of asbestos; removal procedures, where appropriate; and other practices for reducing the hazard. Such training shall be obtained in a comprehensive course for supervisors, that meets the criteria of EPA's Model Accredited Plan (40 CFR Part 763 Subpart E, Appendix C), such as a course conducted by an EPA-approved or state-approved training provider, certified by EPA or a state, or a course equivalent in stringency, content, and length.
(B) For Class III and IV asbestos work, the qualified person shall be trained in aspects of asbestos handling appropriate for the nature of the work, to include procedures for setting up glove bags and mini-enclosures, practices for reducing asbestos exposures, use of wet methods, the contents of this standard, and the identification of asbestos. Such training shall include successful completion of a course that is consistent with EPA requirements for training of local education agency maintenance and custodial staff as set forth at 40 CFR 763.92(a)(2), or its equivalent in stringency, content, and length. Qualified persons for Class III and Class IV work may also be trained pursuant to the requirements of subsection (o)(4)(A) of this section.
(p) Appendices.
(1) Appendices A, C, D, E, and L to this section are incorporated as part of this section and the contents of these appendices are mandatory.
(2) Appendices B, F, H, I, J, and K to this section are informational and are not intended to create any additional obligations not otherwise imposed or to detract from any existing obligations.
(q) Reports of use (User Registration, Temporary Worksite Notification, and Incident Reporting). See section 5203.
Exception: For Class III operations for which the qualified person determines that the EPA curriculum does not adequately cover the training needed to perform that activity, training shall include as a minimum all the elements included in subsection (k)(9)(H) of this section and in addition, the specific work practices and engineering controls set forth in subsection (g) of this section which specifically relate to that activity, and shall includeFor Class III operations for which the qualified person determines that the EPA curriculum does not adequately cover the training needed to perform that activity, training shall include as a minimum all the elements included in subsection (k)(9)(H) of this section and in addition, the specific work practices and engineering controls set forth in subsection (g) of this section which specifically relate to that activity, and shall include "hands-on" training in the work practices applicable to each category of material that the employee disturbs.




Note: Authority cited: Sections 142.3, 6501.5, 9020, 9021.5, 9030 and 9040, Labor Code. Reference: Sections 142.3, 6501.5, 6501.7, 6501.8, 6501.9, 6502, 9003, 9004(b), 9005, 9006, 9009, 9020, 9021.5, 9030, and 9040, Labor Code; and Section 25910, Health and Safety Code.




Appendix A
OSHA Reference Method Mandatory

This mandatory appendix specifies the procedure for analyzing air samples for asbestos and specifies quality control procedures that must be implemented by laboratories performing the analysis. The sampling and analytical methods described below represent the elements of the available monitoring methods (such as appendix B to this section, the most current version of the OSHA method ID-60, or the most current version of the NIOSH Method 7400) which OSHA considers to be essential to achieve adequate employee exposure monitoring while allowing employers to use methods that are already established within their organizations. All employers who are required to conduct air monitoring under subsection (f) of this section are required to utilize analytical laboratories that use this procedure, or an equivalent method, for collecting and analyzing samples.
Sampling and Analytical Procedure
1. The sampling medium for air samples shall be mixed cellulose ester filter membranes. These shall be designated by the manufacturer as suitable for asbestos counting. See below for rejection of blanks.
2. The preferred collection device shall be the 25-mm diameter cassette with an open-faced 50-mm extension cowl. The 37-mm cassette may be used if necessary but only if written justification for the need to use the 37-mm filter cassette accompanies the sample results in the employee's exposure monitoring record. Other cassettes such as the Bell-mouth may be used within the limits of their validation. Do not reuse or reload cassettes for asbestos sample collection.
3. An air flow rate between 0.5 liter/min and 2.5 liters/min shall be selected for the 25-mm cassette. If the 37-mm cassette is used, an air flow rate between 1 liter/min and 2.5 liters/min shall be selected.
4. Where possible, a sufficient air volume for each air sample shall be collected to yield between 100 and 1,300 fibers per square millimeter on the membrane filter. If a filter darkens in appearance or if loose dust is seen on the filter, a second sample shall be started.
5. Ship the samples in a rigid container with sufficient packing material to prevent dislodging the collected fibers. Packing material that has a high electrostatic charge on its surface (e.g., expanded polystyrene) cannot be used because such material can cause loss of fibers to the sides of the cassette.
6. Calibrate each personal sampling pump before and after use with a representative filter cassette installed between the pump and the calibration devices.
7. Personal samples shall be taken in the "breathing zone" of the employee (i.e., attached to or near the collar or lapel near the worker's face).
8. Fiber counts shall be made by positive phase contrast using a microscope with an 8 to 10 X eyepiece and a 40 to 45 X objective for a total magnification of approximately 400 X and a numerical aperture of 0.65 to 0.75. The microscope shall also be fitted with a green or blue filter.
9. The microscope shall be fitted with a Walton-Beckett eyepiece graticule calibrated for a field diameter of 100 micrometers (+/- 2 micrometers).
10. The phase-shift detection limit of the microscope shall be about 3 degrees measured using the HSE phase shift test slide as outlined below.
a. Place the test slide on the microscope stage and center it under the phase objective.
b. Bring the blocks of grooved lines into focus.
Note: The slide consists of seven sets of grooved lines (ca. 20 grooves to each block) in descending order of visibility from sets 1 to 7, seven being the least visible. The requirements for asbestos, tremolite, anthophyllite, and actinolite counting are that the microscope optics must resolve the grooved lines in set 3 completely, although they may appear somewhat faint, and that the grooved lines in sets 6 and 7 must be invisible. Sets 4 and 5 must be at least partially visible but may vary slightly in visibility between microscopes. A microscope that fails to meet these requirements has either too low or too high a resolution to be used for asbestos, tremolite, anthophyllite, and actinolite.
c. If the image deteriorates, clean and adjust the microscope optics. If the problem persists, consult the microscope manufacturer.
11. Each set of samples taken will include 10% field blanks or a minimum of 2 field blanks. These blanks must come from the same lot as the filters used for sample collection. The field blank results shall be averaged and subtracted from the analytical results before reporting. A set consists of any sample or group of samples for which an evaluation for this standard must be made. Any samples represented by a field blank having a fiber count in excess of the detection limit of the method being used shall be rejected.
12. The samples shall be mounted by the acetone/triacetin method or a method with an equivalent index of refraction and similar clarity.
13. Observe the following counting rules.
a. Count only fibers equal to or longer than 5 micrometers. Measure the length of curved fibers along the curve.
b. In the absence of other information, count all particles as asbestos that have a length-to-width ratio (aspect ratio) of 3 to 1 or greater.
c. Fibers lying entirely within the boundary of the Walton-Beckett graticule field shall receive a count of 1. Fibers crossing the boundary once, having one end within the circle, shall receive the count of one half (1/2). Do not count any fiber that crosses the graticule boundary more than once. Reject and do not count any other fibers even though they may be visible outside the graticule area.
d. Count bundles of fibers as one fiber unless individual fibers can be identified by observing both ends of an individual fiber.
e. Count enough graticule fields to yield 100 fibers. Count a minimum of 20 fields; stop counting at 100 fields regardless of fiber count.
14. Blind recounts shall be conducted at the rate of 10 percent.
Quality Control Procedures
1. Intralaboratory program. Each laboratory and/or each company with more than one microscopist counting slides shall establish a statistically designed quality assurance program involving blind recounts and comparisons between microscopists to monitor the variability of counting by each microscopist and between microscopists. In a company with more than one laboratory, the program shall include all laboratories and shall also evaluate the laboratory-to-laboratory variability.
2. a. Interlaboratory program. Each laboratory analyzing asbestos, tremolite, anthopyllite, and actinolite samples for compliance determination shall implement an interlaboratory quality assurance program that as a minimum includes participation of at least two other independent laboratories. Each laboratory shall participate in round robin testing at least once every 6 months with at least all the other laboratories in its interlaboratory quality assurance group. Each laboratory shall submit slides typical of its own work load for use in this program. The round robin shall be designed and results analyzed using appropriate statistical methodology.
b. All laboratories should participate in a national sample testing scheme such as the Proficiency Analytical Testing Program (PAT), the Asbestos Registry sponsored by the American Industrial Hygiene Association (AIHA).
3. All individuals performing asbestos, tremolite, anthopyllite, and actinolite analysis must have taken the NIOSH course for sampling and evaluating airborne asbestos, tremolite, anthopyllite, and actinolite dust or an equivalent course.
4. When the use of different microscopes contributes to differences between counters and laboratories, the effect of the different microscope shall be evaluated and the microscope shall be replaced, as necessary.
5. Current results of these quality assurance programs shall be posted in each laboratory to keep the microscopists informed.




Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.

Appendix B
Sampling and Analysis (Non-mandatory)

Matrix Air:

OSHA Permissible Exposure Limits:
Time Weighted Average............ 0.1 fiber/cc
Excursion Level (30 minutes)..... 1.0 fiber/cc


Collection Procedure:
A known volume of air is drawn through a 25-mm diameter cassette containing a mixed-cellulose ester filter. The cassette must be equipped with an electrically conductive 50-mm extension cowl. The sampling time and rate are chosen to give a fiber density of between 100 to 1,300 fibers/mm 2 on the filter.

Recommended Sampling Rate.... 0.5 to 5.0 liters/
minute (L/min)
Recommended Air Volumes:
Minimum...................... 25 L
Maximum...................... 2,400 L


Analytical Procedure:
A portion of the sample filter is cleared and prepared for asbestos fiber counting by Phase Contrast Microscopy (PCM) at 400X. Commercial manufacturers and products mentioned in this method are for descriptive use only and do not constitute endorsements by USDOL-OSHA. Similar products from other sources can be substituted.
1. Introduction
This method describes the collection of airborne asbestos fibers using calibrated sampling pumps with mixed-cellulose ester (MCE) filters and analysis by phase contrast microscopy (PCM). Some terms used are unique to this method and are defined below: Asbestos: A term for naturally occurring fibrous minerals. Asbestos includes chrysotile, crocidolite, amosite (cummingtonite-grunerite asbestos), tremolite asbestos, actinolite asbestos, anthophyllite asbestos, and any of these minerals that have been chemically treated and/or altered. The precise chemical formulation of each species will vary with the location from which it was mined. Nominal compositions are listed:

Chrysotile.............. Mg 3 Si 2 O 5 (OH) 4
Crocidolite............. Na 2 Fe 3 2 Fe 2 3+ Si 8 O 22 (OH) 2
Amosite................. (Mg,Fe) 7 Si 8 O 22 (OH) 2
Tremolite-actinolite.... Ca 2 (Mg,Fe) 5 Si 8 O 22 (OH) 2

Anthophyllite........... (Mg,Fe) 7 Si 8 O 22 (OH) 2


Asbestos Fiber: A fiber of asbestos which meets the criteria specified below for a fiber.
Aspect Ratio: The ratio of the length of a fiber to it's diameter (e.g. 3:1, 5:1 aspect ratios).
Cleavage Fragments: Mineral particles formed by comminution of minerals, especially those characterized by parallel sides and a moderate aspect ratio (usually less than 20:1).
Detection Limit: The number of fibers necessary to be 95% certain that the result is greater than zero.
Differential Counting: The term applied to the practice of excluding certain kinds of fibers from the fiber count because they do not appear to be asbestos.
Fiber: A particle that is 5 m m or longer, with a length-to-width ratio of 3 to 1 or longer.

Field: The area within the graticule circle that is superimposed on the microscope image.
Set: The samples which are taken, submitted to the laboratory, analyzed, and for which, interim or final result reports are generated.
Tremolite, Anthophyllite, and Actinolite: The non-asbestos form of these minerals which meet the definition of a fiber. It includes any of these minerals that have been chemically treated and/or altered.
Walton-Beckett Graticule: An eyepiece graticule specifically designed for asbestos fiber counting. It consists of a circle with a projected diameter of 100 plus or minus 2 m m (area of about 0.00785 mm 2) with a crosshair having tic-marks at 3- m m intervals in one direction and 5- m m in the orthogonal direction. There are marks around the periphery of the circle to demonstrate the proper sizes and shapes of fibers. This design is reproduced in Figure 1. of this appendix. The disk is placed in one of the microscope eyepieces so that the design is superimposed on the field of view.
1.1. History

Early surveys to determine asbestos exposures were conducted using impinger counts of total dust with the counts expressed as million particles per cubic foot. The British Asbestos Research Council recommended filter membrane counting in 1969. In July 1969, the Bureau of Occupational Safety and Health published a filter membrane method for counting asbestos fibers in the United States. This method was refined by NIOSH and published as P & CAM 239. On May 29, 1971, OSHA specified filter membrane sampling with phase contrast counting for evaluation of asbestos exposures at work sites in the United States. The use of this technique was again required by OSHA in 1986. Phase contrast microscopy has continued to be the method of choice for the measurement of occupational exposure to asbestos.
1.2. Principle
Air is drawn through a MCE filter to capture airborne asbestos fibers. A wedge shaped portion of the filter is removed, placed on a glass microscope slide and made transparent. A measured area (field) is viewed by PCM. All the fibers meeting defined criteria for asbestos are counted and considered a measure of the airborne asbestos concentration.
1.3. Advantages and Disadvantages
There are four main advantages of PCM over other methods:
(1) The technique is specific for fibers. Phase contrast is a fiber counting technique which excludes non-fibrous particles from the analysis.
(2) The technique is inexpensive and does not require specialized knowledge to carry out the analysis for total fiber counts.
(3) The analysis is quick and can be performed on-site for rapid determination of air concentrations of asbestos fibers.
(4) The technique has continuity with historical epidemiological estimates of expected disease can be inferred from long-term determinations of asbestos exposures.
The main disadvantage of PCM is that it does not positively identify asbestos fibers. Other fibers which are not asbestos may be included in the count unless differential counting is performed. This requires a great deal of experience to adequately differentiate asbestos from non-asbestos fibers. Positive identification of asbestos must be performed by polarized light or electron microscopy techniques. A further disadvantage of PCM is that the smallest visible fibers are about 0.2 m m in diameter while the finest asbestos fibers may be as small as 0.02 m m in diameter. For some exposures, substantially more fibers may be present than are actually counted.
1.4. Workplace Exposure
Asbestos is used by the construction industry in such products as shingles, floor tiles, asbestos cement, roofing felts, insulation and acoustical products. Non-construction uses include brakes, clutch facings, paper, paints, plastics, and fabrics. One of the most significant exposures in the workplace is the removal and encapsulation of asbestos in schools, public buildings, and homes. Many workers have the potential to be exposed to asbestos during these operations.
About 95% of the asbestos in commercial use in the United States is chrysotile. Crocidolite and amosite make up most of the remainder. Anthophyllite and tremolite or actinolite are likely to be encountered as contaminants in various industrial products.
1.5. Physical Properties
Asbestos fiber possesses a high tensile strength along its axis, is chemically inert, non-combustible, and heat resistant. It has a high electrical resistance and good sound absorbing properties. It can be weaved into cables, fabrics or other textiles, and also matted into asbestos papers, felts, or mats.
2. Range and Detection Limit
2.1. The ideal counting range on the filter is 100 to 1,300 fibers/mm 2 With a Walton-Beckett graticule this range is equivalent to 0.8 to 10 fibers/field. Using NIOSH counting statistics, a count of 0.8 fibers/field would give an approximate coefficient of variation (CV) of 0.13.
2.2. The detection limit for this method is 4.0 fibers per 100 fields or 5.5 fibers/mm 2. This was determined using an equation to estimate the maximum CV possible at a specific concentration (95% confidence) and a Lower Control Limit of zero. The CV value was then used to determine a corresponding concentration from historical CV vs fiber relationships. As an example:
Lower Control Limit (95% Confidence) = AC - 1.645(CV)(AC)
Where:
AC = Estimate of the airborne fiber concentration (fibers/cc) Setting the Lower Control Limit = 0 and solving for CV:
0 = AC - 1.645(CV)(AC)
CV = 0.61
This value was compared with CV vs. count curves. The count at which CV = 0.61 for Leidel-Busch counting statistics or for an OSHA Salt Lake Technical Center (OSHA-SLTC) CV curve (see Appendix A for further information) was 4.4 fibers or 3.9 fibers per 100 fields, respectively. Although a lower detection limit of 4 fibers per 100 fields is supported by the OSHA-SLTC data, both data sets support the 4.5 fibers per 100 fields value.
3. Method Performance - Precision and Accuracy
Precision is dependent upon the total number of fibers counted and the uniformity of the fiber distribution on the filter. A general rule is to count at least 20 and not more than 100 fields. The count is discontinued when 100 fibers are counted, provided that 20 fields have already been counted. Counting more than 100 fibers results in only a small gain in precision. As the total count drops below 10 fibers, an accelerated loss of precision is noted.
At this time, there is no known method to determine the absolute accuracy of the asbestos analysis. Results of samples prepared through the Proficiency Analytical Testing (PAT) Program and analyzed by the OSHA-SLTC showed no significant bias when compared to PAT reference values. The PAT samples were analyzed from 1987 to 1989 (N=36) and the concentration range was from 120 to 1,300 fibers/mm(2).
4. Interferences
Fibrous substances, if present, may interfere with asbestos analysis. Some common fibers are:
fiberglass anhydrite plant fibers perlite veins gypsum some synthetic fibers membrane structures sponge spicules diatoms microorganisms wollastonite
The use of electron microscopy or optical tests such as polarized light, and dispersion staining may be used to differentiate these materials from asbestos when necessary.
5. Sampling
5.1. Equipment
5.1.1. Sample assembly. Conductive filter holder consisting of a 25-mm diameter, 3-piece cassette having a 50-mm long electrically conductive extension cowl, Backup pad, 25-mm, cellulose. Membrane filter, mixed-cellulose ester (MCE), 25-mm, plain, white, 0.4- to 1.2- m m pore size. Notes:
(a) DO NOT RE-USE CASSETTES. (b) Fully conductive cassettes are required to reduce fiber loss to the sides of the cassette due to electrostatic attraction. (c) Purchase filters which have been selected by the manufacturer for asbestos counting or analyze representative filters for fiber background before use. Discard the filter lot if more than 4 fibers/100 fields are found. (d) To decrease the possibility of contamination, the sampling system (filter-backup pad-cassette) for asbestos is usually preassembled by the manufacturer. (e) Other cassettes, such as the Bell-mouth, may be used within the limits of their validation.
5.1.2. Gel bands for sealing cassettes.
5.1.3. Sampling pump. Each pump must be a battery operated, self- contained unit small enough to be placed on the monitored employee and not interfere with the work being performed. The pump must be capable of sampling at the collection rate for the required sampling time.
5.1.4. Flexible tubing, 6-mm bore.
5.1.5. Pump calibration.
Stopwatch and bubble tube/burette or electronic meter.
5.2. Sampling Procedure
5.2.1. Seal the point where the base and cowl of each cassette meet with a gel band or tape.
5.2.2. Charge the pumps completely before beginning.
5.2.3. Connect each pump to a calibration cassette with an appropriate length of 6-mm bore plastic tubing. Do not use luer connectors - the type of cassette specified above has built-in adapters.
5.2.4. Select an appropriate flow rate for the situation being monitored. The sampling flow rate must be between 0.5 and 5.0 L/min for personal sampling and is commonly set between 1 and 2 L/min. Always choose a flow rate that will not produce overloaded filters.
5.2.5. Calibrate each sampling pump before and after sampling with a calibration cassette in-line (Note: This calibration cassette should be from the same lot of cassettes used for sampling). Use a primary standard (e.g. bubble burette) to calibrate each pump. If possible, calibrate at the sampling site.
Note: If sampling site calibration is not possible, environmental influences may affect the flow rate. The extent is dependent on the type of pump used. Consult with the pump manufacturer to determine dependence on environmental influences. If the pump is affected by temperature and pressure changes, correct the flow rate using the formula shown in the section "Sampling Pump Flow Rate Corrections" at the end of this appendix.
5.2.6. Connect each pump to the base of each sampling cassette with flexible tubing. Remove the end cap of each cassette and take each air sample open face. Assure that each sample cassette is held open side down in the employee's breathing zone during sampling. The distance from the nose/mouth of the employee to the cassette should be about 10 cm. Secure the cassette on the collar or lapel of the employee using spring clips or other similar devices.
5.2.7. A suggested minimum air volume when sampling to determine TWA compliance is 25 L. For Excursion Limit (30 min sampling time) evaluations, a minimum air volume of 48 L is recommended.
5.2.8. The most significant problem when sampling for asbestos is overloading the filter with non-asbestos dust. Suggested maximum air sample volumes for specific environments are:

Environment Air Vol. (L)
Asbestos removal operations (visible dust) 100.
Asbestos removal operations (little dust) 240.
Office environments. 400 to 2,400.


CAUTION: Do not overload the filter with dust. High levels of non- fibrous dust particles may obscure fibers on the filter and lower the count or make counting impossible. If more than about 25 to 30% of the field area is obscured with dust, the result may be biased low. Smaller air volumes may be necessary when there is excessive non-asbestos dust in the air.
While sampling, observe the filter with a small flashlight. If there is a visible layer of dust on the filter, stop sampling, remove and seal the cassette, and replace with a new sampling assembly. The total dust loading should not exceed 1 mg.
5.2.9. Blank samples are used to determine if any contamination has occurred during sample handling. Prepare two blanks for the first 1 to 20 samples. For sets containing greater than 20 samples, prepare blanks as 10% of the samples. Handle blank samples in the same manner as air samples with one exception: Do not draw any air through the blank samples. Open the blank cassette in the place where the sample cassettes are mounted on the employee. Hold it open for about 30 seconds. Close and seal the cassette appropriately. Store blanks for shipment with the sample cassettes.
5.2.10. Immediately after sampling, close and seal each cassette with the base and plastic plugs. Do not touch or puncture the filter membrane as this will invalidate the analysis.
5.2.11. Attach and secure a sample seal around each sample cassette in such a way as to assure that the end cap and base plugs cannot be removed without destroying the seal. Tape the ends of the seal together since the seal is not long enough to be wrapped end-to-end. Also wrap tape around the cassette at each joint to keep the seal secure.
5.3. Sample Shipment
5.3.1. Send the samples to the laboratory with paperwork requesting asbestos analysis. List any known fibrous interferences present during sampling on the paperwork. Also, note the workplace operation(s) sampled.
5.3.2. Secure and handle the samples in such that they will not rattle during shipment nor be exposed to static electricity. Do not ship samples in expanded polystyrene peanuts, vermiculite, paper shreds, or excelsior. Tape sample cassettes to sheet bubbles and place in a container that will cushion the samples in such a manner that they will not rattle.
5.3.3. To avoid the possibility of sample contamination, always ship bulk samples in separate mailing containers.
6. Analysis
6.1. Safety Precautions
6.1.1. Acetone is extremely flammable and precautions must be taken not to ignite it. Avoid using large containers or quantities of acetone. Transfer the solvent in a ventilated laboratory hood. Do not use acetone near any open flame. For generation of acetone vapor, use a spark free heat source.
6.1.2. Any asbestos spills should be cleaned up immediately to prevent dispersal of fibers. Prudence should be exercised to avoid contamination of laboratory facilities or exposure of personnel to asbestos. Asbestos spills should be cleaned up with wet methods and/or a High Efficiency Particulate Air (HEPA) filtered vacuum.
CAUTION: Do not use a vacuum without a HEPA filter - It will disperse fine asbestos fibers in the air.
6.2. Equipment
6.2.1. Phase contrast microscope with binocular or trinocular head.
6.2.2. Widefield or Huygenian 10X eyepieces (NOTE: The eyepiece containing the graticule must be a focusing eyepiece. Use a 40X phase objective with a numerical aperture of 0.65 to 0.75).
6.2.3. Kohler illumination (if possible) with green or blue filter.
6.2.4. Walton-Beckett Graticule, type G-22 with 100 plus or minus 2 m m projected diameter.
6.2.5. Mechanical stage. A rotating mechanical stage is convenient for use with polarized light.
6.2.6. Phase telescope.
6.2.7. Stage micrometer with 0.01-mm subdivisions.
6.2.8. Phase-shift test slide, mark II (Available from PTR optics Ltd., and also McCrone).
6.2.9. Precleaned glass slides, 25 mm X 75 mm. One end can be frosted for convenience in writing sample numbers, etc., or paste-on labels can be used.
6.2.10. Cover glass #1 1/2.
6.2.11. Scalpel (#10, curved blade).
6.2.12. Fine tipped forceps.
6.2.13. Aluminum block for clearing filter (see Appendix D).
6.2.14. Automatic adjustable pipette, 100-to 500- m L.
6.2.15. Micropipette, 5 m L.
6.3. Reagents
6.3.1. Acetone (HPLC grade).
6.3.2. Triacetin (glycerol triacetate).
6.3.3. Lacquer or nail polish.
6.4. Standard Preparation
A way to prepare standard asbestos samples of known concentration has not been developed. It is possible to prepare replicate samples of nearly equal concentration. This has been performed through the PAT program. These asbestos samples are distributed by the AIHA to participating laboratories.
Since only about one-fourth of a 25-mm sample membrane is required for an asbestos count, any PAT sample can serve as a "standard" for replicate counting.
6.5. Sample Mounting
Note: See Safety Precautions in Section 6.1. before proceeding. The objective is to produce samples with a smooth (non-grainy) background in a medium with a refractive index of approximately 1.46. The technique below collapses the filter for easier focusing and produces permanent mounts which are useful for quality control and interlaboratory comparison.
An aluminum block or similar device is required for sample preparation.
6.5.1. Heat the aluminum block to about 70 deg.C. The hot block should not be used on any surface that can be damaged by either the heat or from exposure to acetone.
6.5.2. Ensure that the glass slides and cover glasses are free of dust and fibers.
6.5.3. Remove the top plug to prevent a vacuum when the cassette is opened. Clean the outside of the cassette if necessary. Cut the seal and/or tape on the cassette with a razor blade. Very carefully separate the base from the extension cowl, leaving the filter and backup pad in the base.
6.5.4. With a rocking motion cut a triangular wedge from the filter using the scalpel. This wedge should be one-sixth to one-fourth of the filter. Grasp the filter wedge with the forceps on the perimeter of the filter which was clamped between the cassette pieces. DO NOT TOUCH the filter with your finger. Place the filter on the glass slide sample side up. Static electricity will usually keep the filter on the slide until it is cleared.
6.5.5. Place the tip of the micropipette containing about 200 m L acetone into the aluminum block. Insert the glass slide into the receiving slot in the aluminum block. Inject the acetone into the block with slow, steady pressure on the plunger while holding the pipette firmly in place. Wait 3 to 5 seconds for the filter to clear, then remove the pipette and slide from the aluminum block.
6.5.6. Immediately (less than 30 seconds) place 2.5 to 3.5 m L of triacetin on the filter (NOTE: Waiting longer than 30 seconds will result in increased index of refraction and decreased contrast between the fibers and the preparation. This may also lead to separation of the cover slip from the slide).
6.5.7. Lower a cover slip gently onto the filter at a slight angle to reduce the possibility of forming air bubbles. If more than 30 seconds have elapsed between acetone exposure and triacetin application, glue the edges of the cover slip to the slide with lacquer or nail polish.
6.5.8. If clearing is slow, warm the slide for 15 min on a hot plate having a surface temperature of about 50 deg.C to hasten clearing. The top of the hot block can be used if the slide is not heated too long.
6.5.9. Counting may proceed immediately after clearing and mounting are completed.
6.6. Sample Analysis
Completely align the microscope according to the manufacturer's instructions. Then, align the microscope using the following general alignment routine at the beginning of every counting session and more often if necessary.
6.6.1. Alignment
(1) Clean all optical surfaces. Even a small amount of dirt can significantly degrade the image.
(2) Rough focus the objective on a sample.
(3) Close down the field iris so that it is visible in the field of view. Focus the image of the iris with the condenser focus. Center the image of the iris in the field of view.
(4) Install the phase telescope and focus on the phase rings. Critically center the rings. Misalignment of the rings results in astigmatism which will degrade the image.
(5) Place the phase-shift test slide on the microscope stage and focus on the lines. The analyst must see line set 3 and should see at least parts of 4 and 5 but, not see line set 6 or 6. A microscope/microscopist combination which does not pass this test may not be used.
6.6.2. Counting Fibers
(1) Place the prepared sample slide on the mechanical stage of the microscope. Position the center of the wedge under the objective lens and focus upon the sample.
(2) Start counting from one end of the wedge and progress along a radial line to the other end (count in either direction from perimeter to wedge tip). Select fields randomly, without looking into the eyepieces, by slightly advancing the slide in one direction with the mechanical stage control.

(3) Continually scan over a range of focal planes (generally the upper 10 to 15 m m of the filter surface) with the fine focus control during each field count. Spend at least 5 to 15 seconds per field.
(4) Most samples will contain asbestos fibers with fiber diameters less than 1 m m. Look carefully for faint fiber images. The small diameter fibers will be very hard to see. However, they are an important contribution to the total count. (continued)