Health Hazard

Evaluation 

) Report 

HETA 85-021-1654 

PORTSMOUTH NAVAL SHIPYARD

PORTSMOUTH) NEW HAMPSHIRE 

/ 
PREFACE 


)EI 	 The Hazard Evaluations and Technical Assistance Branch of NIOSH conducts field 

investigations of possible health hazards in the workplace. Trese 

investigations are conducted under the authority of Section 20(a)(c) of the 

Occupational · Safety and Health Act of 1970, 2~ U.S.C. 669(a)(6) which 

authorizes the Secretary of Health and Human Services, following a written 

request from any employer or authorized representative of employees, to 

determine whether any substance normally found in the place of employment has 

potentially toxic effects in such concentrations as used or found. 

The Hazard Evaluations and Technical Assistance Branch also provides, upon 

request, medical, nursing, and industrial hygiene technical and consultative 

assistance (TA) to Federal, state, and local agencies; labor; industry and 

other groups or individuals to control occupational health hazards and to 

prevent related trauma and disease. 

Mention of o~pany names or products does not constitute endorsement by the 

National Ins titute for Occupational Safety and Health. 
HETA 85-021-1654 NIOSH Inves t igator:

Portsmouth Naval Shipyard Kevin P. Me Manus, I. H. 

January 1986 

I. SLMMARY 

On October 15, 1984 the Natio~al Institute for Occupational Safety and 

Heal t h (NIOSH) received a request to conduct a Health Hazard 

Evaluation at the Portsmouth Naval Shipyard, Portsmouth, New 

Hampshire. The request was concerned with complaints of nose bleeds 

and upper respiratory tract irritation among employees in the 

insulation shop due to possible exposure to asbestos, fibrous glass and magnesium silicates. 

NIOSH conducted environmental sampling and a questionnaire medical 

survey between April 8-11, 1985. Twenty-four air samples were 

collected throughout Building 2 (insulation shop) and analyzed for 

total fiber count. Four additional samples were analyzed by transmission electron microscopy (TEM) for fiber identification. 

Nine air samples were collected to determine respirable dust (silica) 

exposure, primarily in the cement room. Bulk samples of each of the ­ three types of cement were collected and analyzed using x-ray 

defraction for determination of quartz content. 

The results of environmental sampling for asbestos fibers, silica, and 

respirable dust were all below recommended exposure limits and not 

significantly different from background readings which could be 

measured outdoors. The laboratory indicated that the TEM results were 

not significantly different from zero. 

Seventy-three (out of a possible 100) completed medical questionnaires 

were received from insulators on all three shifts. The questionnaire 

was designed to be self-administered to determine the incidence of 

self reported symptoms, especially nose bleeds. 

The symptom most frequently reported was sneezing, experienced by 59 

employees (81%), followed by runny nose 53 (73%), frequent colds 52 

(72%), and skin irritation 52 (72%). Forty-six employees (63%) 

reported having some occurrence of nose bleeds. 

Based on the results of this investigation it has been determined that 

employee symptoms were probably caused by the irritating properties of 

magnesium silicate (dessicant), portland cement (alkaline) and fibrous 

glass (mechanical action), and poor work practices which result in 

direct contact and transfer of irritating dusts. Although airborne 

exposures are within the environmental criteria, and symptoms were not 

evidence of systemic injury, action should be taken to reduce the 

incidence of upper respiratory irritation which is a result of 

workplace exposure. Recommendations are found in the body of the 

reQort to help reduce the amount of irritation. 

Ke ywords: Sic 3731, Irritation, l'l!agnesium-Silicat e , Portland Cement, 

Upper Respiratory, 1-.Jose-bleeds, Fibrous-glass. 
Bulk samples of each of t he t hree ty pes of cement wer e collectcc o~C:: 

analyzed using x-ray defracti on f or determina t ion of quar t z conte nt . 

Seventy-three complet ed medical ques t ionnaires were received from ::~ 

t otal of 100 insulators on all t hr ee shift s , a 73% r esponse r ate. 

The ques t ionnaire was 	designeJ t o be self-administer ed t o deter mine 

t he incidence of self 	reported symptoms, especiall y nose bleeds. The 

ques t ionnaire contains a cer tain bias , as specific symptoms were 

eli cit ed. However, this investigation was not purporting t o 

clini cally measure t ile presence or severity of nose bleeds. 

V. EVALUATION CRITERIA 

Environmental Standards 

The environmental criteria described below are intended to 

represent airborne concentrations of substances to which workers 

may be exposed for eight hours a day, 40 hours per week for a 

working lifetime without adverse health effects. Because of wide 

variation in individual susceptibility, a small percentage of 

workers may experience discomfort from some substances at 

concen t rations at or below the recommended criteria.2 A smaller 

percentage may be more seriously affected by aggravation of a 

pre-existing condition or by a hypersensitivity reaction. The 

t ime-weighted average (TWA) exposure refers to the average 

concentration during a normal 8-hour workday. The Short-Term 

Exposure Limit is the maximum allowable concentration, or ceiling, 

to which workers can be exposed during a period of up to 15 

minutes, provided that no more than four excursions per day are 

permitted, with at least 60 minutes between exposure periods. 

The primary sources of environmental evaluation criteria 

considered for this study were: 1) NIOSH criteria documents and 

recommendations, 2) t he American Conference of Governmental 

Industrial Hygienists (ACGIH) Threshold Limit Values (TLV's), and 

3) the U.S. Department of Labor (OSHA) federal occupational health 

standards. The criteria judged most appropriate for this study 

are as follows: 

NIOSH Recommended 

Substance Criteria ACGIH TLV OSHA Standard 

Crystalline Silica 50 ug!M3 10 mg!MI 10 mg!Ml 

%Si02+2 %Si02+2 

Fibrous Glass 	 3 fiberslcc or 10 mgllv13 15 mg/M3 

5 mgfM3 

As bestos 	 0.1 fiberslcc 0.2-2.0 flee 2.0 flee 

Magnesium Silicate NIA 	 10 mg/M3 15 mg!M3 

@) Calcium Silicat e NIA 	 10 mgllv1 3 15 mgll-.1 3 

Portland Cement NIA 	 10 mglr-.1 3 50 mppcf 
2 . 


I_) 


II. INTRODUCTION 

On October 15, 1984 the National Instit ute for Occupational Safety and 

Health (NIOSH) received a request from an authorized representative of 

the United Brotherhood of Carpenters and Joiners of America to conduct 

a Health Hazard Evaluation at the Portsmouth Naval Shipyard, 

Portsmouth, New Hampshire.· The request v1as concerned with employee complaints of nose bleeds and upper respiratory tract irritation in 

the insulation shop due to possible exposure to asbestos, fibrous 

glass and magnesium silicates. 

III . BACKGROUND 

The insulation shop is located on the west side of dry-dock #1, inside 

the controlled industrial area of the shipyard. Approximately 100 

employees work out of this shop. Only a few employees work in the 

shop full time. Asbestos is not currently used as an insulating 

material in the shop. However, the same shop previously was used for 

preparation and storage of asbestos insulation material. Attempts have been made to remove all asbestos material from the building and 

its surfaces. New walls,ceilings and floor coverings have been added 

to seal in any residual asbestos and prevent it from becoming airborne. 

The insulation shop presently uses fibrous glass, magnesium silicate 

and portland cement to manufacture pipe insulation for Navy ships and 

submarines. Most employees of this shop also perform rip-outs and 

pipe covering on board these vessels. Air-supplied respirators are 

used during all rip-outs. 

Employee exposures while ship-board was not a concern of the 

insulators at this time. Rather, their concern was due to numerous 

complaints of rhinitis, nose bleeds and upper respiratory irritation 

while working inside the insulation shop. 

A NIOSH industrial hygienist conducted environmental sampling and a 

questionnaire medical survey between April 8-11, 1985. Aggregate questionnaire data was provided to both Union and Management officials 

on April 11. All environmental results, except TEM analysis, were 

telephoned to Shipyard officials On May 15, 1985. 

IV. EVALUATION DESIGN AND METHODS 

Twenty-four air samples were collected throughout Building 2 

(insulation shop) ~nd analyzed according to NIOSH Method 7400 for 

total fiber count. Four additional samples were analyzed by 

transmission electron microscopy (TEM) for fiber identification. 

Air samples were collected at a height approximating the breathing 

zone of employees. They were collected using Nucleopore 25mm mixed 

cellulose ester filters (open face) and MSA Model G battery-powered 

sampling pumps calibrated at 2.0 liters per minute (lpm). 

Nine air samples were collected using tared PVC filters attached to a 

cyclone and analyzed gravimetrically to determine respirable dust 

(sUica) Fxpc.sure, primarily in the cement room. 
0 

Bulk s~np es of each of the three types of cement were collected ~d 

anal yzed using x-ray defraction for determination of quartz content. 

Seventy-three completed medical quest ionnaires were received from 8. 

total of 100 insul ators on all t hree shifts , a 73% response rate. 

The questionnaire was desianeJ to be self-administered t o de termine 

t he incidence of self 	reported symptoms, especially nose bleeds. The 

questionnaire contains a certain bias, as specific symptoms were 

elicited. However, this investigation was not purporting t o 

clinically measure the presence or severity of nose bleeds. 

V. EVALUATION CRITERIA 

Environmental Standards 

The environmental criteria described below are intended to 

represent airborne concentrations of substances to which workers 

may be exposed for eight hours a day, 40 hours per week far a 

working lifetime without adverse health effects. Because of wide 

variation in individual susceptibility, a small percentage of 

workers may experience discomfort from some substances at 

concentrations at or below the recommended criteria.2 A smaller 

percentage may be more seriously affected by aggravation of a 

pre-existing condition or by a hypersensitivity reaction. The 

time-weighted average (TWA) exposure refers to the average 

concentration during a normal 8-hour workday. The Short-Term 

Exposure Limit is the maximum allowable concentration, or ceiling, 

to which workers can be exposed during a period of up to 15 

minutes, provided that no more than four excursions per day are 

permitted, with at least 60 minutes between exposure periods. 

The primary sources of environmental evaluation criteria 

considered for this study were: 1) NIOSH criteria documents and 

recommendations, 2) the American Conference of Governmental 

Industrial Hygienists (ACGIH) Threshold Limit Values (TLV's), and 

3) the U.S. Department of Labor (OSHA) federal occupational health 

standards. The criteria judged most appropriate for this study 

are as follows: 

NIOSH Recommended 

Substance Criteria ACGIH TLV OSHA Standard 

Crystalline Silica 50 ug!M3 10 mg!M3 10 mg/M2 

%Si02+2 %Si02+2 

Fibrous Glass 	 3 fiberslcc or 10 mgiM3 15 mg/M3 

5 mgfM3 

Asbest os 	 0.1 fiberslcc 0. 2-2.0 flee 2.0 flee 

lv1 agnesium Silicate NIA 	 10 mg/M3 15 mg/M3 

Calcium Silicate NIA 	 10 mg!M 3 15 mg!lv1 3 

Portland Cement NIA 	 lU mg/rv1 3 50 mppcf 
4. 


NOTE: 	 ppm =parts per million parts of air 

mg/1-4? = milligrams per cubic meter of air ug/1~3 = micrograms per cubic meter of air 

mppcf = million? of particles per cubic foot 

Health EFfects 

Crystalline Silica 

The crystalline forms of silica can cause severe tissue damage 

when inhaled. Silicosis is a form of pulmonary fibrosis caused by the deposition of fine particles of crystalline silica in the 

lungs. Symptoms usually develop insidiously, with cough, 

shortness of breath, chest pain, weakness, wheezing, and 

nonspecific chest illnesses. Silicosis usually occurs after years of exposure, but may appear in a shorter time if exposure 

concentrations are very high. This latter form is referred to as 

rapidly-developing silicosis, and its etiology and pathology are 

not as well understood. Silicosis is usually diagnosed through chest x-rays, occupational exposure histories, and pulmonary 

function tests. The manner in which silica affects pulmonary

tissue is not fully understood, and theories have been proposed 

based on the physical shape of the crystals, their solubility,_ toxicity to macrophages in the lungs, or their crystalline 

structure. There is evidence that cristobalite and tridymite,

which have a different crystalline form from that of quartz, have 

a greater capacity to produce silicosis.3 ­

Dusts 

The potential dust exposures related to work in the insulation 

shop include cement, calcium silicate, magnesium silicate and 

fibrous glass. All of these dusts possess irritant properties: 

cement due to its' alkalinity, calcium and magnesium silicate due 

to their absorbent (hygroscopic) quality and fibrous glass due to 

mechanical action. 

The irritant properties of all these dusts can cause irritation of 

the sensory receptors of the bronchial mucous membrane, leading to 

a reflex contraction of the smooth muscle (bronchial 

obstruction). These dusts may be generally classified as 

nuissance dusts, but exposure to them may exacerbate pre-existing 

chest conditions like asthma, bronchiectasis, and bronchitis.4 

Asbestos 

Increased health risk resulting from occupational exposure to 

asbestos has been well documented in the scientific literature. 

Initially, asbestos was associated with a chronic and debilitating 

lung disease called asbestosis, which normally occurred following 

long-term exposures to high levels of asbestos fibers. More 

recently, asbestos has also been linked to several types of 

cancer, including mesothelioma (a rare cancer of the chest and 

abdominal lining) and cancers of the lung, esophagus, stomach and 

col on. These cancers usually appear many years after the initial 
J . 

contact with asbestos, and sometimes result from short-term and/ or 

low leve l exposures. This indicates that there may not be a "safe" level of exposure to asoes t os for the elimination of all 

c3ncer risk. Additionally, cigarette smoking in combination with 

asbestos exposure greatly increases tne risk of developing lung 

cancer.5 

The Occupational Safety and Health Administration (OSHA) standard 

for asbestos, limits exposure to 2 fibers/cc (greater than 5 

microns in length) averaged over an 8-hour workday with a ceiling

concentration of 10 fibers/cc not to be exceeded over a 

fifteen-minute period. There is also a provision for medical 

monitoring of workers routinely exposed to levels in excess of 0.1 

fibers/cc. This exposure standard ·was devised to minimize the 

risk of developing asbestosis. OSHA is presently going through 

the rule-making process to lower this standard. The American 

Conference of Governmental Industrial Hygienists (ACGIH), an 

independent scientific body, also recommends chrysotile asbestos 

exposures be limit ed to between 0.2 and 2 fibers/cc, depending on 

the type of asbestos present, over an 8-hour workday (with a 

notation that asbestos is a human carcinogen). 

NIOSH currently recommends that occupational exposure to asbestos ­ be kept to the lowest feasible level that can reliably be 

determined. This recommendation is based on the proven human 

carcinogenicity of asbestos and on the absence of a known 

threshold exposure level below which there is no risk of cancer. 

For most industrial settings, the lowest feasible limit for 

reliable detection of asbestos corresponds to a level of 0.1 

fibers/cc. 

Fibrous Glass 

Different dimensions of fibrous glass will produce different 

biologic effects. Large diameter (greater than 3.5 microns)

fibers have been found to cause skin, eye, and upper respiratory 

tract irritation; a relatively low frequency of fibrotic changes; 

and a very slight indication of an excess mortality due to 

nonmalignant respiratory disease. Smaller diameter (less than 3.5 

microns) fibrous glass has not been conclusively related to health 

effects in humans but glass fibers of this dimension have only 

been produced since the 1960's. Smaller diameter fibers have the 

ability to penetrate to the alveoli and this potential is cause 

for concern. On the basis of available information, NIOSH does 

not consider fibrous glass to be a substance that produces cancer 

as a result of occupational exposure. Fibrous glass does not 

appear to possess the same potential as asbestos for causing 

health hazard.6 

VI. RESULTS 

~ Environmental 

The results of silica analysis of the three bulk samples indicated 

t hat HI-Temp contained 9.4% quartz; Portland Cement, less than 

0. 75%quartz; and Super, 3.2% quartz. 
6. 


·~] 

Nine es~irable dust air samples indicated e xposures ranging from 

8. 7 ug/1v\ t o 30 ug/lvt::S . Based on the results of the bulk 

samples , t he_maximum silica e xposure would range from 0.82 uy.M3 

t o 2.82 A~ . These results indicate very little respirabl e 

dust, and are summarized as follows: 

Sample No. Location Volume Result (ug!M2) Criteria 

5iiica Dust 

4913911 Lunch room 1229 L 29 50 5000 

41CJ13915 Workbench 750 L 30 50 5000 

41013916 Mud room 755 L 17 50 5000 

41013953 Lunch room 751 L 20 50 5000 

41113957 Lunchroom 765 L 27 50 5000 

41113962 Mud room 753 L 8.7 50 5000 

4913963 Workbench 1258 L 28 50 5000 

4913964 Mud room 1299 L ll.5 50 5000 

41113266 Workbench 751 L 27 50 5000 

Eighteen samples were analyzed by phase contrast microscopy for 

total fibers. The calculated result is the total number of fibers 

(all types) greater than 5 microns in length per cubic centimeter 

or air. Results are summarized below. 

Sample no. Location Volume Result (Fibers/cc) 

410117 Band Saw 886 Liters 0.002 

410119 Lunchroom 850 *0.0017 

410125 Foreman's office 844 *0. 0018 

410138 Fab Workbench 874 *0.0017 

4lll37 

4lll40 

Storage rm 

Attic 

852 

882 

0.0018 

*0.0017 

411141 Lunchroom 900 *0.0017 

4lll43 Fab Workbench 890 *0.0017 

411145 Band Saw 888 *0.0017 

49ll Personal 410 *0.0036 

4912 Personal 352 0.005 

4915 Fab Workbench 833 0.0018 

49127 Pad room 884 0.0017 

49224 Band Saw 632 *0.0023 

49229 Pad room 634 *0.0023 

49232 Fab Workbench 630 *0.0023 

49236 Lunchroom 562 *0.0027 

411148 Pad room 894 *0.0017 

* = Less than the limit of detection calculated for that sample. 

Results that are reported above the limit of detection have not 

been field blank correct ed, and as such the reported numoers are 

probably higher th an actual e xposure. , Re sults less than 0. 01 f / cc 

are generally not considered significant for the phase cont rast 

me t hod. 
7. 


The four samples selected for transmission electron microscop y 

were collected in the storage room, lunchroom, pad room, and at 

the band saw operation. ln all cases , the laboratory reported

t hat the asbes tos fib er concentration was not significantly 

different from zero. In only one case (band saw) was an asbestos 

fiber found that could be observed by phase contrast microscopy. 

The TEM analyses revealed t he following characteristics. 

Sample No. 4913 (Lunchroom) contained one amosite fiber, 1.88 

microns in lenyth and 0.56 microns in diameter, within the area of 

the sample analyzed. This amounts to 2,936 fibers per filter, or 

0.003 fibers per cubic centimeter (flee). The laboratory reported 

a total of 46,972 structures on the filter composed of many large

particles and combustion aerosol. 

Sample No. 4914 (Band Saw) contained one tremolite fiber, 10.31 

microns in length and 0.31 microns in diameter, within the area of 

the filter analyzed. This was the only fiber that cou~d have been 

observed by phase contrast microscopy. This calculates to 3,014 

fibers per filter, or 0.003 flee. The laboratory reported a total 

of 198,953 total structures on the filter composed of acicular 

particles with pointed ends. 

Sample No. 410128 (Pad Room) contained one chrysotile fiber, 1.19 

microns in length and 0.06 microns in diameter, within the area of 

the filter analyzed. This calculates to 2,851 fibers per filter, 

or 0.003 flee. The laboratory reported a total of 79,832 total 

structures on the filter composed of acicular particles with 

pointed ends and a few large particles. 

Sample No. 410134 (Storage Room) contained two chrysotile fibers 

and one amosite fiber, ranging from 1.38 to 2.50 microns in length and 0.06 microns in diameter, within the area of the filter 

analyzed. This calculates to 8,870 fibers per filter, or 0.010 

flee. The laboratory reported a total of 47,308 total structures 

on the filter composed of acicular particles, spheres, and 

combustion aerosol. 

Medical 

Sixty-seven males and six females responded to the health effects 

questionnaire, a 73% response rate. The average age of 

respondents was 35, and the average length of employment 6.6 

years. Thirty-two of the seventy-three (44%) were smokers. 

The symptom most frequently reported was sneezing, experienced by 

59 employees (81%), followed by runny nose 53 (73%), frequent 

colds 52 (72%), and skin irritation 52 (72%). Forty-six employees

(63%) reported having some occurrence of nose bleeds. 

Those who indicated a positive r esponse to nose bleeds were asked 

to iden t ify the frequency and severity of t he problem. The 

average frequency of nose bleeds was approximately twice per week, 

while the severity of the problem was most commonly, spotting when 

blowing ones nose. 
Only one employee responded that the nose bleeds do not stop on 

their own. Eleven employees reported t hat nose bleeds were more 

severe than spotting , but stop on their own. However, their 

occurrence was l ess fre quent than the aver age . 

The presence of symptoms was not shift dependent. Employees on 

all three shifts reported sympt oms with equal frequency. 

Only 19 employees indicated that they have reported the nose 

bleeds to the shipyard medical department (40% of those reporting the symptom) . 

VII. DISCUSSION 

The results of the phase contrast microscopy, which looks at all 

fibers of all types greater than 5 microns in length, indicated very 

low airborne fiber contamination within the building. The results are 

not significantly different from background readings which could be 

measured outdoors. 

The T8~ results, which counts all asbestos fibers, even the ones too 

small to be seen by phase contrast microscopy and thus not included in 

the OSHA standard, indicated that asbestos levels are at or below 

background levels. The laboratory indicated that the results were not 

significantly different from zero. 

The amount of respirable dust measured in the shop was extremely low. 

Even if one were to assume that all of the respirable dust was free 

crystalline silica, the highest concentration measured was 30 

micrograms per cubic meter, which is below the NIOSH criteria of 50 

ugM3. 

The results of the questionnaire survey indicated that a significant 

number of employees are experiencing symptoms related to work in this 

building. However, employee exposures to chemicals within the 

building are within all environmental criteria. The results suggest that the employee symptoms are not a result of systemic action, 

rather, they are likely the result of the irritating properties of the 

dusts. Observat~on of the work practices indicated that the most 

likely exposure mechanism is direct physical contact. The dusts enter 

the upper respiratory region because employees with dust on their 

hands, rub their nose and deposit the irritating dust . 

VIII. CONCLUSIONS 

Based on the results of this investigation it has been determined that 

employee symptoms were probably caused by the irritating properties of 

magnesium silicate (dessicant), portland cement (alkaline) and fibrous 

glass (mechanical action), and poor work practices which resulted in 

direct contact and transfer of the irritating dusts. Although 

airborne exposures are within the environmental criteria, and symptoms 

were not evidence of systemic injury, action should be taken to reduce 

the incidence of upper respiratory irritation which is a result of 

workplace exposure. 
9. 


IX. RECCMMENOATION 

Employees should pay rigorous attention to personal hygiene to prevent 

the transmission of the dust from their hands to their nose and eyes. 

Barrier creams or moisturizers ~ay also alleviate much of the 

irritation caused by these materials. 

X. AUTHORSHIP AND ACKNOWLEDGEMENTS 

Report Prepared By: Kevin P. lv1dvtanus, I. H. 

Regional Industrial Hygienist

NIOSH - Region l 

1401 JFK Federal Building 

Boston, Massachusetts 

Originating Office Hazard Evaluation and Technical 

Assistance Branch 

Division of Surveillance, Hazard 

Evaluations and Field Studies 

Cincinnati, Ohio 
XI. REFERENCES 

1. 	American Conference of Governmental Industrial Hygienists. ~ } 

Documentation of the threshold limit values. 4th ed. Cincinnati, Ohio: ACGIH, 1980. 

2. 	 National Institute for Occupational Safety and Heal t h. NIOSH 


manual of analytical met~ods. Vol 1, 2nd ed. Cincinnati, OH: 


National Institute for Occupational Safety and Health, 1977. 


(DHEW (NIOSH) publication no. 77-157-A). 


3. 	National Institute for Occupational Safety and Health . Criteria 


for a recommended standard: occupational exposure to crystalline


silica. Cincinnati, Ohio: National Institute for Occupational 


Safety and Health, 1975. (DHEW publication no. (NIOSH) 75-120). 


4. 	National Institute for Occupational Safety and Health. 


Occupat ional diseases: a guide to their recognition. Revised 


ed. Cincinnati, OH: National Institute for Occupational Safety 


and Health, 1977. (DHEW (NIOSH) publication no. 77-181). 


5. 	National Institute for Occupational Safety and Health. Criteria 


for a recommended standard: occupational exposure to Asbestos. _ 
 Cincinnati, Ohio: National Institute for Occupational Safety and 


Health, 1977. (DHEW publication no. (NIOSH) 77-169). 


6. 	National Institute for Occupational Safety and Health. Criteria 


for a recommended standard: occupational exposure to fibrous 


glass. Cincinnati, Ohio: National Institute for Occupational 


Safety and Health, 1977. (OHEW publication no. (NIOSH) 77-152). 


7. 	American Conference of Governmental Industrial Hygienists. 


Threshold limit values for chemical substances and physical agents 
 in the workroom environment with intended changes for 1981. 


Cincinnati, Ohio: ACGIH, 1981. . 


8. 	American Conference of Governmental Industrial Hygienists. 


Documentation of the threshold limit values. 4th ed. Cincinnati,
 Ohio: ACGIH, 1980. 

9. 	Hawley, GG. The condensed chemical dictionary. New York: Van 


Nostrand Reinhold Company, 1982. 


10. 	 Patty FA. Patty's industrial hygiene and toxicology. Vol 

II--toxicology, 3rd revised ed. New York: John Wiley &Sons, 

1978. 
XII . DISTRIBUTION AND AVAILABILITY OF REPORT 

Copies of t his r eport are currently available upon reques t from NIOSH , Divisi on of Standards Development and Technology Transfer, 4676 

Columbia Parkway, Cincinnati, Ohio 45226. After 90 days, the report 

will be available through the National Technical Information Service 

(NTIS), 5285 Port Royal Road, Springfield, Virginia, 22161 . Information regarding its availability t hrough NTIS can be obtained 

from the NIOSH Publications Office at the Cincinnati address. Copies 

of this report have been sent to: 

l. Portsmouth Naval Shipyard, Portsmouth, N.H. 

2. Metal Trades Council, Portsmouth, N.H. 

3. 	 United Brotherhood of Carpenters and Joiners of America 

Washington, D.C. 

4. U.S. Department of Labor - OSHA, Region 1, Boston, Ma. 

For the purpose of informing affected employees, copies of this report 

shall be posted by the employer in a prominent place accessible to the 

employees for a period of 30 calendar days. 
DEPARTMENT OF HEALTH AND HUMAN SERVICES 

PUBLIC HEALTH SERVICE 

CENTERS FOR DISEASE CONTROL 

NATIONAL INSTITUTE FOFt OCCUPATIONAL SAFETY ANO HEALTH 

ROBERT A. TAFT LABOfiATORIES 

4676 COLUMBIA PARKWAY, CINCINNATI, OHIO 45226 

OFFICIAL BUSINESS 

PENALTY FOR PRIVATE USE, S300 I . 

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POSTAGE ANO FEES PAlO 

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