| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
RESEARCH AND PRACTICE |
Anthony D. LaMontagne is with the Centre for the Study of Health and Society, Department of Public Health, School of Population Health, University of Melbourne, Melbourne, Victoria, Australia. J. Michael Oakes is with the Department of Epidemiology, School of Public Health, University of Minnesota, Minneapolis. Ruth N. Lopez Turley is with the Department of Sociology, University of Wisconsin, Madison.
Correspondence: Requests for reprints should be sent to Anthony D. LaMontagne, Centre for the Study of Health and Society, Department of Public Health, School of Population Health, University of Melbourne, Melbourne, VIC 3010, Australia (e-mail: alamonta{at}unimelb.edu.au).
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
Objectives. We assessed long-term trends in ethylene oxide (EtO) worker exposures for the purposes of exposure surveillance and evaluation of the impacts of the Occupational Safety and Health Administration (OSHA) 1984 and 1988 EtO standards.
Methods. We obtained exposure data from a large commercial vendor and processor of EtO passive dosimeters. Personal samples (87 582 workshift [8-hr] and 46 097 short-term [15-min] samples) from 2265 US hospitals were analyzed for time trends from 1984 through 2001 and compared with OSHA enforcement data.
Results. Exposures declined steadily for the first several years after the OSHA standards were set. Workshift exposures continued to taper off and have remained low and constant through 2001. However, since 1996, the probability of exceeding the short-term excursion limit has increased. This trend coincides with a decline in enforcement of the EtO standard.
Conclusions. Results indicate the need for renewed intervention efforts to preserve gains made following the passage and implementation of the 1984 and 1988 EtO standards.
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
Exposure or hazard surveillance is relatively underdeveloped in relation to occupational health outcome surveillance, which has a much longer history.2,4,5 Although both exposure and health outcome surveillance are relevant to addressing the unacceptably high burden of occupational disease,6 health outcome surveillance is infeasible for many occupational diseases, such as those with multifactorial etiologies or long latency periods. Nevertheless, exposure surveillance continues to be underutilized as a surveillance strategy as well as an effectiveness measure in governmental policy evaluation and other intervention research.4,7,8 One reason for this underuse is the lack of data sources. Although the US Occupational Safety and Health Administration (OSHA) Integrated Management Information System data on occupational exposures is broad based both geographically and in terms of the range of hazards represented,5,9 data on personal exposures to specific agents over time is limited. The National Institute for Occupational Safety and Health (NIOSH) National Occupational Exposure Survey also has broad coverage but little in the way of quantitative measurements. Although NIOSH is planning new exposure surveillance initiatives,10 substantial quantitative exposure databases on specific hazards are only rarely reported on. One strategy for addressing this data gap is to improve relations between researchers and data gatherers (employers) to make use of the vast amount of exposure data routinely collected by employers and other groups.4,8
From a perspective of intervention effectiveness research, the literature is dominated by reports on the development, implementation, and evaluation of worksite-level intervention programs.11 Evaluations of policy-level interventions, such as OSHA standards, are relatively few but provide valuable guidance for the implementation of current policy as well as new policymaking.11–13 Finally, legislative mandates requiring governmental agencies to demonstrate the need for occupational health and safety regulations, their effectiveness, and the achievement of performance benchmarks point to the potential utility of integrating exposure surveillance with intervention effectiveness research.4,7,8,14
In this article, we analyze long-term ethylene oxide (EtO) exposure trends in US hospitals using an integrated approach that draws from the perspectives of both traditional surveillance and newer intervention effectiveness research. EtO is a known human carcinogen, a potential reproductive hazard, an allergic sensitizer, a potential asthmagen, and a potent neurotoxin that continues to be used widely for the sterilization of heat- and moisture-sensitive medical supplies.15,16 An OSHA section 6(b) EtO health standard (hereafter referred to as the Standard) was promulgated in 1984. The Standard included a permissible exposure limit (PEL) of 1 ppm and an action level (AL) of 0.5 ppm for EtO workshift exposures (time-weighted average parts per million over 8 hours).17 In 1988, OSHA revised the Standard to include a short-term excursion limit (STEL) of 5 ppm for EtO (time-weighted average parts per million over 15 minutes).18
|
METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
From 1984 through 2001, a total of 256 666 EtO samples were processed and results were entered into the vendor’s database. The database was cleaned using the series of steps described below to generate analytical data sets for workshift and short-term samples. It has been previously established that the greatest concentration of potentially EtOexposed workers is in the healthcare/hospital sector, where EtO is used for the sterilization of heat- and moisture-sensitive medical supplies.23 This finding is reflected in the exposure monitoring data obtained, wherein 86% of the measurements were taken in hospitals (Standard Industrial Code 806). We have restricted the analyses reported here to hospitals to (1) make the industrial context homogeneous and (2) focus on the employment sector, where the bulk of OSHA and NIOSH EtO intervention efforts have been focused; this is a best-case scenario of potential policy-level intervention impacts on EtO exposures.24 In addition to nonhospital samples, we also excluded area samples, "test" samples created by the vendor for quality control purposes, samples with nonsensical dates, and samples from 2002 (because it was an incomplete year of data). Many samples were not clearly identifiable by sample duration (time in minutes) as either workshift or short-term samples. Workshift samples were defined as samples with a duration of 6 to 10 hours (8 hours ±2 hours). OSHA specifies that short-term samples are to be 15 minutes in duration. Although this was the mean sampling time for short-term samples, we also included short-term samples between 5 and 25 minutes in duration (15 minutes ±10 minutes). These cleaning steps resulted in 2 data sets containing 113 830 workshift and 62 329 short-term EtO samples from the hospital sector from 1984 through 2001—68% of the 256 666 measurements.
EtO-specific OSHA regulatory activity in hospitals was determined with the use of OSHA enforcement data requested as follows from OSHA’s Integrated Management Information System: all OSHA inspections, citations, and penalties related to the EtO standard (specified as Standard no. 1910.1047 for EtO) in the health services sector (Major Group Standard Industrial Code 80) from 1984 to the present.
Analytic Data, Unit of Analysis, and Primary Outcome Measures
Workshift measurements were taken from 28 373 hospital workers in 2265 hospitals across the United States. On average, each worker was tested 4.0 times, up to 375 times. The short-term measurements were taken from 18 894 workers in 1735 hospitals. On average, each worker was sampled 3.3 times, up to 343 times. However, this article’s unit of analysis is the hospital rather than the individual worker. This is because the primary aim of OSHA policy is to create safer workplaces and because OSHA assesses compliance at the level of the workplace or organization. Hospital- or organization-level analyses are commonly conducted in other exposure time trend studies.12,25
The primary outcome measures for this article are EtO exposures dichotomized to indicate whether or not dosimeter measurements in observed hospitals exceeded OSHA-specified limits 1 or more times per calendar year. A repeated measures or panel data set with binary values for end points and indicator variables for hospital-years was constructed so that we may report proportions or probabilities of a given hospital exceeding the AL, the PEL, and the STEL in any observed year.
Statistical Procedures
Exposure rates within and among hospitals were analyzed descriptively and modeled with logistic regression for each of the 3 exposure limit end points (yes = 1 and no = 0 for PEL, AL, and STEL, respectively). Independent variables included year of observation (1985 through 2001), as well as a quadratic year term for time, to test for nonlinearities, suggested by previous descriptive analyses.19,20 The data held no other covariates.
A random effect for hospital was included in each regression model to permit the estimation of within-hospital slopes over time. Random effect models were selected over population-averaged generalized estimating equations or fixed effect models because of our goals for surveillance and policy analysis. The advantage of random effect regression is that it uses all available data and permits inference to the larger population of hospitals. Fixed effects regression is more appropriate, making inferences specific to hospitals in the same sample, and often results in the underuse of some information. Population-averaged generalized estimating equation estimators yield parameters more akin to between-hospital effects.26–28 In addition, we used robust standard errors to account for clustering and misspecification.28–30 However, it is important to note that all findings were robust to model choice, giving us greater confidence in our conclusions. All analyses were conducted using Stata version 7.0 (Stata Corp, College Station, Tex).
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
displays hospital-level descriptive statistics. The first row shows that each hospital typically reported workshift samples over 4 to 5 years. At least 1 hospital was observed in only 1 year, and at least 1 was observed in all 17 years. Other descriptive statistics on monitoring activity may be similarly read from Table 1. Figure 1 displays the number of worker-level samples collected and the number of hospitals conducting monitoring over time. It is clear that EtO measurement/monitoring increased in the first several years after the 1984 and 1988 standards were set, followed by a decline since the early 1990s.
|
|
displays the percentages of hospitals exceeding the EtO exposure limits 1 or more times in a given year. For workshift samples (PEL), this percentage ranged from 0.9% (in 2001) to 21.0% (in 1988). For short-term samples (STEL), the range was from 6.9% (in 1996) to 32.2% (in 1988). General trends for the 2 exposure outcomes are similar in that percentages declined steadily over the first several years after the promulgation of the respective exposure limits: the 1984 workshift exposure limit (in the original full Standard) and the 1988 short-term exposure limit (amended Standard). However, the most recent 5 years of data (1997—2001) suggest an increase in the percentage of hospitals exceeding the short-term OSHA exposure limit.
|
displays (random effects) logistic regression models with coefficients for time (in calendar years). Parameter estimates for both logistic (data not shown) and random effects logistic models indicate that the probabilities of exceeding each of the OSHA limits decreased significantly over the first several years after the 1984 Standard and the 1988 amendment were set. Of note are the coefficients for the squared year term in the STEL and AL models. These are positive and significant, indicating that these exposure trends are curvilinear or increasing.
|
, we present the predicted probabilities of exceeding the exposure limits over time in Figure 2b. We omitted 95% confidence intervals from this panel because they were indistinguishable from their respective trend lines on the scale presented. This graphic conveys clearly the implications of the positive quadratic parameter for short-term exposures. It can be seen that the probability of a hospital’s exceeding 1 of the OSHA limits decreased sharply over the first several years after the Standard was set. But also clearly visible is an upward trend in exceeding the short-term limit from 1996 through 2001—no upward trend is apparent for workshift exposures. The positive quadratic parameter for AL exposures reflects a slight curvilinearity in the early years after the passage of the 1984 Standard.
The decreasing numbers of hospitals conducting personal exposure monitoring in recent years (Figure 1) raises the possibility that attrition bias may explain the recent upward trend in short-term exposures (i.e., that hospitals with more overexposures might be more likely to continue monitoring than those with lower exposures, enriching the sample in later years for hospitals with higher exposures). Although we cannot rule out this confounding explanation with certainty, because the random effects model enables assessment of exposure trends over time within hospitals, the explanatory power of the threat is minimized. Moreover, analyses of hospitals with lengthy observation periods show trends consistent with those reported here. For instance, restricting analysis to hospitals reporting 5 or more years of data only marginally changed coefficients (from –0.450 to –0.423 for year and from 0.015 to 0.014 for year-squared in the STEL model) and did not affect statistical significance.
National EtO-specific OSHA regulatory pressure in the health services industry is summarized in Figure 2c. Of note is the coincidence of a sharp drop-off in OSHA regulatory pressure (around 1996) and the upward trend in short-term exposures (Figure 2a and 2b).
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
Our results indicate widespread implementation of exposure-monitoring requirements of the 1984 EtO Standard by hospitals across the country. In a previous detailed study of the implementation of the EtO Standard in Massachusetts hospitals, we observed that most hospitals conducted initial exposure monitoring 1 or more years after OSHA-required dates.20 The steep upward trend in the number of hospitals conducting monitoring from 1984 through 1990 in this article suggests that this was also the case nationally. This increase occurred despite the high visibility of OSHA’s EtO rule making (e.g., EtO legislation was closely followed in professional journals concerned with health care material management) and the considerable outreach efforts on the part of both OSHA and NIOSH (reviewed elsewhere24). This delayed response suggests the need for additional strategies to improve the timeliness of implementation of OSHA requirements.
In terms of the observed exposure trends, this article verifies previously documented downward EtO exposure trends for the first several years after the 1984 Standard and its 1988 amendment19,20,31 but does so using a single, internally consistent, much larger, and much more broadly representative exposure data source. This initial downward exposure trend is consistent with previous findings that health services industries responded along the lines of OSHA’s recommended control strategies and that OSHA’s control strategies were both technologically and economically feasible.20,24,31 However, the findings of this study suggest that there has been a backsliding in prevention and control efforts in recent years. The high statistical power afforded by this new data source has enabled the detection of a recent upward trend in exposures exceeding the short-term exposure limit. Studies of most OSHA-regulated hazardous substance exposures have shown steady declines or a flattening of exposures over the similar time scales of 15 or more years after regulation began.25,32 Because of the potential policy and practice implications of this unusual finding, careful examination of the strengths and limitations of the evidence is warranted.
Study Strengths and Limitations
There are several points to review in relation to our data source. The benefits of analyzing the employer-collected data in this study include the following: (1) the quantity of the data dwarfs all other sources described in published reports to date; (2) the large number of exposure measurements were drawn from a large number of hospitals that were distributed geographically widely across the United States; and (3) we had the opportunity to gain insights into a primary goal of OSHA regulation, that is, to stimulate organizations to continuously assess and improve occupational health and safety conditions. Limitations include potential biases owing to the nonrandom nature of the sampling and the limited information on potential determinants of exposure levels (e.g., no information on job tasks or titles through which subgroup variation could be assessed). The lack of information on other covariates, such as job tasks and titles, is offset to some extent by the specific focus on hospitals, where there is a small number of task or exposure groups: those involved with operation of sterilization equipment and changing EtO gas cylinders as well as those working in the vicinity of the sterilization equipment.33–35 Yet overall and in practical terms, the size of the database and knowledge from other studies of the prevalent practice in hospitals of routine rather than worst-case monitoring20 suggest that the data presented in this article more closely represent nationwide exposure conditions than other available sources.
Possible Explanations of Upward Trends
Although the descriptive and random effects analysis support the finding of an upward short-term exposure trend in recent years,36 possible explanations of this as an artifactual finding must be considered. Selection or attrition bias as an explanation is mitigated by use of the random effects regression. It is also possible that the recent upward STEL trend could be explained by changes in prevalent sampling practices. We do not have data to assess this possibility and therefore cannot strictly rule out a systematic change in sampling practices within hospitals. However, in order for this to account for the observed trends, hospitals across the country would have had to have moved consistently from routine periodic monitoring to worst-case monitoring over the same calendar years. We believe this to be extremely unlikely and are not aware of any evidence to suggest that this might be the case.
We believe that the observed upward STEL trend most likely represents an increase in the probability of overexposures in hospitals in recent years. If this is the case, then a finding from the previous Massachusetts hospital study20 suggests that there may also be a parallel increase in accidental releases of EtO that result in short-term high-level exposures to small groups of workers that are not detected by personal monitoring; in this study, it was shown that even though a minority of hospitals across Massachusetts had exceeded OSHA limits over the 1990–1993 period, many more had experienced accidental releases that were not captured by personal monitoring.20 Short-term high-dose exposures are of particular concern because of EtO’s dose-rate effect in terms of adduct formation, which is relevant to EtO health effects ranging from carcinogenicity and reproductive toxicity to allergic sensitization and asthma.16,20 A more stringent exposure limit (0.1 ppm PEL) was considered for the 1984 Standard based on low-dose health effects but was ruled out because 1 ppm was the lowest exposure level that was then technically feasible to measure.31 Combining knowledge of emerging and established EtO health concerns, such as asthmas and cancers, respectively, indicates that the upward exposure trends suggested by this study’s findings will have health significance.
The upward STEL trend follows a drop-off in OSHA inspections, citations, and fines under the EtO Standard. This suggests that decreased OSHA regulatory pressure may be an important determinant of this observed trend. This interpretation is consistent with the deterrence theory on which OSHA regulations are based and is supported by well-designed studies of the impacts of OSHA enforcement on injury outcomes, working conditions, and regulatory compliance.37–39 Other possible contributors to the observed trend could include decreased OSHA and NIOSH outreach and diversion of employers’ attention from EtO hazards because of more recent emphases on other hospital hazards (e.g., blood-borne pathogens, tuberculosis). From October 2000 through September 2001, the EtO Standard accounted for 14 citations out of a total 4097 in the Health Services major group (Standard Industrial Code 80).40 EtO was the 38th most frequently cited OSHA Standard out of 80 cited. By comparison, the most frequently cited OSHA Standards in Health Services over the same time period were blood-borne pathogens (1213 citations) and hazard communication (323 citations).
Conclusions
Hospital worker exposures to EtO declined steadily in the several years after OSHA’s 1984 workshift and 1988 short-term exposure limit were set. However, in recent years there has been an early warning sign of upward exposure trend in short-term exposures. This indicates the need for renewed regulatory and other intervention efforts to protect health care workers from EtO’s carcinogenic, allergic-sensitizing, reproductive, and other hazards. The coincident drop in OSHA regulatory pressure suggests that without an adequately resourced and active OSHA, substantial improvements in working conditions such as those made in the first decade after the 1984 EtO Standard was set could be eroded.
The goal of public health surveillance is to provide early warning of potential problems to enable their timely control.5,41 For occupational health hazards whose health effects are not amenable to surveillance—a characteristic of EtO that also is shared by most other hazardous occupational exposures—only exposure or hazard surveillance has the potential to effect timely feedback and control.42 Occupational exposure or hazard-focused surveillance efforts should be expanded for this reason as well as for their value in providing insights into the effectiveness of OSHA regulations and other interventions, and for meeting government performance requirements.4,7
|
Acknowledgments |
|---|
The authors sincerely thank Douglas Kruger at Kem Medical Products Corporation for making this study possible by kindly providing access to EtO exposure data, Dr Joe Dubois at OSHA for providing Integrated Management Information System regulatory enforcement data, and Drs R. F. Herrick and J. Stewart for their contributions at the beginning of the study.
Human Participant Protection
The study’s protocol was reviewed and approved by the institutional review boards of the Dana-Farber Cancer Institute, the Harvard School of Public Health, and the University of Minnesota.
|
Footnotes |
|---|
Accepted for publication April 25, 2003.
|
References |
|---|
|
TOPABSTRACTINTRODUCTIONMETHODSRESULTSDISCUSSIONReferences |
|---|
2. National Occupational Research Agenda. Atlanta, Ga: Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; 1996.
3. Rosenstock L, Olenec C, Wagner GR. The national occupational research agenda: a model of broad stakeholder input into priority setting. Am J Public Health. 1998;88:353–356.
4. LaMontagne AD, Herrick RF, Van Dyke MV, Martyny JW, Ruttenber AJ. Exposure databases and exposure surveillance: promise and practice. Am Ind Hyg Assoc J. 2002;63:205–212.
5. Fine LJ. Surveillance and occupational health. Int J Occup Environ Health. 1999;5(1):26–29.[Medline]
6. Leigh JP, Markowitz SB, Fahs M, Shin C, Landrigan PJ. Occupational injury and illness in the United States. Estimates of costs, morbidity, and mortality. Arch Intern Med. 1997;157:1557–1568.
7. Gomez MR. Exposure surveillance tools needed in agency GPRA plans. Am Ind Hyg Assoc J. 1998;59:371–374.
8. Gomez MR. Exposure assessment must stop being local. Appl Occup Environ Hyg. 2000;15:15–20.[Medline]
9. Stewart PA, Rice C. A source of exposure data for occupational epidemiology studies. Appl Occup Environ Hyg. 1990;5:359–363.
10. Boiano JM, Hull RD. Development of a National Occupational Exposure Survey and Database associated with NIOSH hazard surveillance initiatives. Appl Occup Environ Hyg. 2001;16:128–134.[Medline]
11. Goldenhar LM, LaMontagne AD, Katz T, Heaney C, Landsbergis P. The intervention research process in occupational safety and health: an overview from the NORA Intervention Effectiveness Research Team. J Occup Environ Med. 2001;43:616–622.[Web of Science][Medline]
12. LaMontagne AD. Evaluation of OSHA health standards. In: Levy BS, Wegman DH, eds. Occupational Health: Recognizing and Preventing Work-Related Disease. 4th ed. Philadelphia: Lippincott Williams & Wilkins; 2000:134–135.
13. Stayner L, Kuempel E, Rice F, Prince M, Althouse R. Approaches for assessing the efficacy of occupational health and safety standards. Am J Ind Med. 1996;29:353–357.[Medline]
14. LaMontagne AD, Kelsey KT. OSHA’s renewed mandate for regulatory flexibility review: in support of the 1984 ethylene oxide standard. Am J Ind Med. 1998;34:95–104.[Medline]
15. Ethylene oxide. In: Some Industrial Chemicals. Lyons, France: International Agency for Research on Cancer, World Health Organization; 1994:73–159. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans; Vol 60.
16. LaMontagne AD, Kelsey KT. Ethylene oxide. In: Rom WN, ed. Environmental and Occupational Medicine. 3rd ed. Philadelphia: Lippincott-Raven Publishers; 1998:1145–1155.
17. Occupational Safety and Health Administration. Occupational exposure to ethylene oxide: final standard. 49 Federal Register 25734–25809 (1984).
18. Occupational Safety and Health Administration. Occupational exposure to ethylene oxide; final standard. 53 Federal Register 11414–11438 (1988).
19. Meridian Research Inc. Ethylene oxide: a case study in hazard identification, OSHA regulation, and market response. Final report. Silver Spring, Md: Submitted to Office of Program Evaluation, OSHA, by Meridian Research, Inc; 1992 July 21. Available by request to OSHA.
20. LaMontagne AD, Kelsey KT. Evaluating OSHA’s ethylene oxide standard: employer exposure monitoring activities in Massachusetts hospitals from 1985–1993. Am J Public Health. 1997;87:1119–1125.
21. Puskar MA, Hecker LH. Field validation of passive dosimeters for the determination of employee exposures to ethylene oxide in hospital product sterilization facilities. Am Ind Hygiene Assoc J. 1989;50:30–36.
22. Szopinski FG, Puskar MA, Hecker LH. Field validation of three passive dosimeters for excursion limit monitoring of ethylene oxide. Am Ind Hyg Assoc J. 1991;52:151–157.[Medline]
23. Steenland K, Stayner L, Greife A, et al. Mortality among workers exposed to ethylene oxide. N Engl J Med. 1991;324:1402–1407.[Abstract]
24. LaMontagne AD, Kelsey KT. Evaluating OSHA’s ethylene oxide standard: exposure determinants in Massachusetts hospitals. Am J Public Health. 2001;91:412–417.
25. Coble JB, Lees PSJ, Matanoski G. Time trends in exposure measurements from OSHA compliance inspections in the pulp and paper industry. Appl Occup Environ Hyg. 2001;16:263–270.[Medline]
26. Brown H, Prescott R. Applied Mixed Models in Medicine. New York, NY: John Wiley & Sons; 1999.
27. Hardin JW, Hilbe JM. Generalized Estimating Equations. New York, NY: Chapman & Hall; 2003.
28. Woolridge JM. Econometric Analysis of Cross Section and Panel Data. Cambridge, Mass: MIT Press; 2002.
29. White H. Maximum likelihood estimation of misspecified models. Econometrica. 1982;50(1):1–26.[Web of Science]
30. Long JS, Ervin LH. Using heteroscedasticity consistent standard errors in the linear regression model. Am Statistician. 2000;54:217–224.[Web of Science]
31. Gauging Control Technology and Regulatory Impacts in Occupational Safety and Health—An Appraisal of OSHA’s Analytical Approach. Washington, DC: US Congress Office of Technology Assessment; 1995. Report OTA-ENV-635.
32. Melville R, Lippmann M. Influence of data elements in OSHA air sampling database on occupational exposure levels. Appl Occup Environ Hyg. 2001;16:884–899.
33. Elliott LJ, Ringenburg VL, Morelli-Schroth P, Halperin WE, Herrick RF. Ethylene oxide exposures in hospitals. Appl Ind Hyg. 1988;3:141–145.
34. Elliott L, Mortimer V, Ringenburg V, Kercher S, O’Brien D. Effect of engineering controls and work practices in reducing ethylene-oxide exposure during the sterilization of hospital supplies. Scand J Work Environ Health. 1988;14(suppl 1):40–42.
35. LaMontagne AD, Kelsey KT, Christiani DC, Plantamura D. Ethylene Oxide Health and Safety Manual: Training and Reference Materials on the Safe Use of Ethylene Oxide in Sterilizing Facilities. 2nd ed. Braintree, Mass: Center for Occupational and Environmental Medicine, Massachusetts Respiratory Hospital; 1990.
36. Berk RA, Freedman DA. Statistical Assumptions as Empirical Commitments. Los Angeles, Calif: University of California; 2001. Report A307.
37. McQuiston TH, Zackocs RC, Loomis D. The case for stronger OSHA enforcement—evidence from evaluation research. Am J Public Health. 1998;88:1022–1024.
38. Weil D. If OSHA is so bad, why is compliance so good? RAND J Economics. 1996;27:618–640.[Web of Science]
39. Gray WB, Scholz JT. Does regulatory enforcement work? A panel analysis of OSHA enforcement. Law Society Review. 1993;27:177–213.
40. Occupational Safety and Health Administration Web site. OSH Statistics. Available at: http://www.osha.gov/oshstats/index.html. Accessed October 15, 2002.
41. Halperin W, Baker EL, Monson RR, eds. Public Health Surveillance. New York, NY: Van Nostrand Reinhold; 1992.
42. Fine LJ. The importance of information dissemination in the prevention of occupational cancer. Environ Health Perspect. 1995;103(suppl 8):217–218.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
