Larry J. Elliott

Inhalation Exposure to Formaldehyde: An Overview of Its Toxicology, Epidemiology, Monitoring, and Control

Increasing production and use of formaldehyde in consumer products have resulted in widespread recognition of its acute irritant effects at exposure levels below the current occupational health standard [3 parts per million parts of air (ppm)]. Formaldehyde is an allergic (immunologically mediated) skin sensitizer which may also cause or exacerbate respiratory distress in individuals with preexisting or formaldehyde-induced bronchial hyperreactivity. Formaldehyde gas is a very reactive alkylating agent which is mutagenic in several in vitro test systems. At exposure levels less than one order of magnitude greater than those often found in human occupational and nonoccupational environments, it induces squamous cell carcinomas in the nasal cavity of rats. Recent reviews suggest that formaldehyde exposure should be treated as though it poses a carcinogenic risk to humans and should be reduced to the lowest feasible level. This report reviews information on the epidemiologic evaluation of health effects which may result from hazardous levels of exposure to formaldehyde. Methods for monitoring exposure are discussed in detail because of considerable diversity in the methods used by state health departments for recognition, evaluation and control of nonoccupational exposures. Current guidelines for the evaluation and control of exposures to formaldehyde gas are suggested.

Proposed model for estimating dose to inhabitants of 60Co contaminated buildings

A model to predict the time weighted exposures to gamma radiation was developed for buildings constructed with structural steel having some contamination from 60Co. Several buildings throughout sixteen city blocks in downtown Taipei were built about ten years ago with this material. These buildings were used for residential, business, and educational purposes with radiation levels ranging from background to five hundred times background. A comprehensive epidemiologic study by the National Yang Ming University Medical School in Taipei is underway to study the effects of this exposure to the building occupants. An evaluation of external radiation exposure was performed using survey instruments and thermoluminescent dosimeters. Exposure data from the survey instruments were used in a computer model developed to calculate cumulative radiation exposure estimates for the epidemiologic research. While the survey instrument data provided radiation levels at a point in time, the thermoluminescent dosimeters were placed in fixed locations and on several volunteers for a period of one month to verify the modeling results. The model itself is a mathematical algorithm that provides estimates with minimum and maximum range values by taking into account differences in the survey data between adults and children, variable occupancy patterns, background radiation, and radioactive decay. Several assumptions (background rates, height adjustment values, and occupancy factors) are easily adjusted to improve the estimated radiation exposures. The model predicted the exposures as measured by the thermoluminescent dosimeters with greater reliability for adults than for children. The differences between the two methods were about 10-15% for the adults and about 60% for the child. This strategy, its advantages, limitations, and its performance against actual thermoluminescent dosimeter measurements are presented.

Ethylene Oxide Exposures in Hospitals

Abstract Ethylene oxide (EtO) is used in hospitals as a sterilant of heat-and/or moisture-sensitive hospital supplies and surgical instruments. Comprehensive industrial hygiene surveys were conducted at 12 hospitals to characterize EtO exposure levels for workers in the sterilization areas. Hospitals included in the study were selected to represent a wide range of exposure situations as a result of various engineering controls, administrative controls, and work practices. Sampling results indicated that 8-hour time-weighted average (TWA) personal EtO exposure levels ranged from less than the limit of detection (LOD) of the method to 6.7 ppm, and short-term personal EtO exposures ranged from less than the LOD to 103 ppm. Based upon information regarding the degree of engineering controls and work practices employed, the hospitals were placed in one of four categories. The exposure results for each group of hospitals were compared with the criteria on engineering controls and work practices for that categor...

An Exposure Characterization of a Large Scale Application of a Biological Insecticide, Bacillus Thuringiensis

Abstract The gypsy moth, Lymantria dispar, is one of the most destructive insect pests of trees and shrubs in the United States. Since its introduction in the United States in 1869, the gypsy moth has extensively infested areas of 13 northeastern and mid-atlantic states. Smaller, localized infestations have been found in recent years in 17 other states across the nation. When DDT was available, the gypsy moth was almost eradicated from the United States, but as DDT use was curtailed, the gypsy moth infestations became widespread. The State of Oregon has chosen to primarily use the biological insecticide Bacillus thuringiensis var kurstaki (Bt) to eradicate the gypsy moth from approximately 250,000 acres of forested and urban areas in Lane County, Oregon. Personal exposure and area air monitoring for Bt was conducted to determine occupational and general public exposure potential to Bt. Portable sampling pumps with membrane filters (MF) were used to conduct the sampling. Analysis of the MF for Bt involved ...

Radiation Dose Reconstruction Program of the National Institute for Occupational Safety and Health: overview.

Over the past 65 years, hundreds of thousands of workers have been engaged in nuclear weapons-related activities for the U.S. Department of Energy or its predecessor agencies. To date, almost 27,000 such employees (or their survivors) have filed claims under Part B of the Energy Employees Occupational Illness Compensation Program Act of 2000, which provides monetary compensation and medical benefits to energy employees who have developed certain types of cancer that have been determined, under the guidelines of the program, to have resulted from occupational radiation exposure covered under the Act. Although it is difficult to predict the number of cancer claims that will be evaluated under this program, the number could double or triple. In each case, the processing of a claim requires that the National Institute for Occupational Safety and Health reconstruct the radiation dose received by the employee followed by a determination by the U.S. Department of Labor as to whether the employee was “at least as likely as not” to have sustained the cancer as a result of his or her occupational exposure to ionizing radiation. Although some of the dose assessments are straightforward, many are extremely complex due to (1) missing, non-interpretable, or undocumented records; (2) a wide variety of external and internal exposure conditions; and/or (3) highly variable work assignments and work loads. The program objectives are to process claims in an effective, efficient, and timely manner. One of the initial challenges was to develop the necessary infrastructure to meet these objectives. Subsequent challenges included documenting that assessments are fair and scientifically consistent. Ensuring that each claimant receives the “benefit of the doubt” in any cases where the required background information and data are ambiguous or not available is also an important objective. Fortunately, there are some aspects of the processing requirements that have tended to reduce the complexity, two examples being that compensation is based on exposures that occurred during covered employment after a cancer has developed and that the required dose estimates are for individual body organs, not effective doses. Throughout the process, every effort has been made to ensure that the dose assessments have the support of the best available science.

The National Institute for Occupational Safety and Health Radiation Dose Reconstruction Program: commentary and conclusions.

THE NATIONAL Institute for Occupational Safety and Health (NIOSH) Radiation Dose Reconstruction Program is a complex scientific effort that draws from most of the technical aspects of the health physics profession. As described in the papers of this special edition, these activities involve the assessment of internal and external doses for individuals who were exposed to workplace, environmental, and occupationally related medical sources of ionizing radiation at one or more of over 300 Atomic Weapons Employer (AWE) and U.S. Department of Energy (DOE) facilities. Workers were potentially exposed to one or more of 15 defined categories of ionizing radiation (NIOSH 2002a and b), further complicating the assessments because the records, if available, are often more than 50 years old, and their correct interpretation frequently necessitates detailed reviews of many historical program documents. In many respects, the dose reconstruction component of this program can be best described as health physics archaeology. Throughout the development and conduct of activities under the Energy Employees Occupational Illness Compensation Program Act (EEOICPA), the NIOSH staff, in concert with its technical contractors, has adhered to four underlying principles: (1) all activities should be supported by a strong scientific foundation; (2) this foundation should be consistently and uniformly applied; (3) every effort should be made to perform the dose reconstructions in a timely, efficient, and equitable manner; and (4) the public should be provided ample opportunities to participate, that is, the program should be conducted in what is called as “transparent” a manner as possible while, at the same time, maintaining the privacy of the workers and claimants. The methods through which these principles are being implemented are reflected in the sections that follow.

Ethylene Oxide Exposures to Hospital Sterilization Workers from Poor Ventilation Design

Abstract Employees in the central supply (CS) department of a Midwestern hospital, which used ethylene oxide (EtO) to sterilize medical supplies, reported experiencing multiple symptoms including headaches, dizziness, mucous membrane irritation, vomiting, and smelling a “sweet” odor during a portion of the operating cycle of the sterilizers. To identify the causative agent, air samples were collected and analyzed for EtO, organics, aldehydes, hydrochloric acid, chlorine, carbon monoxide, and carbon dioxide. In addition, air exhaust system flow rates were measured in and around the sterilizers, and the integrity of floor drains below the sterilizers was evaluated. Time-weighted average personal exposure concentrations for EtO ranged from 0.23 to 0.56 ppm among CS employees. These concentrations were below the Occupational Safety and Health Administration permissible exposure limit of 1 ppm, but above the National Institute for Occupational Safety and Health recommended criterion of maintaining EtO exposure...