Cancer Incidence Among Hardmetal Production Workers: The Swedish Cohort

: The cancer incidence was determined for 3713 workers from three plants from 1958 to 2011. The exposure measures were ever/never exposed, duration, cumulative, and mean cobalt concentrations.The incidence of all malignant neoplasms was increased at one plant, but standardized incidence ratio (SIR) was 0.96 for all workers. Lung cancer incidence was increased for all workers, SIR 1.38 (1.01 to 1.85). The lung cancer incidence was associated with shorter employment time and showed no exposure-response. There was decreased incidence for skin cancer. Increased lip cancer incidence found at one of the production plants might be related to diagnostic intensity.Lung cancer incidence showed no correlation to cobalt exposure based on internal comparison. The increased SIR for all workers might be associated with other factors.

A pilot study to determine medical laser generated air contaminant emission rates for a simulated surgical procedure

The U.S. Occupational Safety and Health Administration (OSHA) estimates that half a million health-care workers are exposed to laser surgical smoke each year. The purpose of this study was to establish a methodology to (1) estimate emission rates of laser-generated air contaminants (LGACs) using an emission chamber, and to (2) perform a screening study to differentiate the effects of three laser operational parameters. An emission chamber was designed, fabricated, and assessed for performance to estimate the emission rates of gases and particles associated with LGACs during a simulated surgical procedure. Two medical lasers (Holmium Yttrium Aluminum Garnet [Ho:YAG] and carbon dioxide [CO2]) were set to a range of plausible medical laser operational parameters in a simulated surgery to pyrolyze porcine skin generating plume in the emission chamber. Power, pulse repetition frequency (PRF), and beam diameter were evaluated to determine the effect of each operational parameter on emission rate using a fractional factorial design. The plume was sampled for particulate matter and seven gas phase combustion byproduct contaminants (benzene, ethylbenzene, toluene, formaldehyde, hydrogen cyanide, carbon dioxide, and carbon monoxide): the gas phase emission results are presented here. Most of the measured concentrations of gas phase contaminants were below their limit of detection (LOD), but detectable measurements enabled us to determine laser operation parameter influence on CO2 emissions. Confined to the experimental conditions of this screening study, results indicated that beam diameter was statistically significantly influential and power was marginally statistically significant to emission rates of CO2 when using the Ho:YAG laser but not with the carbon dioxide laser; PRF was not influential vis-a-vis emission rates of these gas phase contaminants.

Urinary concentrations of toxic substances: an assessment of alternative approaches to adjusting for specific gravity

Alternative approaches of adjusting urinary concentration of cadmium for differences in specific gravity of biological samples were assessed. The main analysis used 2922 cadmium-in-urine samples collected in the period 1968-1989 from workers at a UK nickel-cadmium battery facility. Geometric means of cadmium-in-urine, adjusted and unadjusted for specific gravity, were obtained for 21 different values of specific gravity ranging from 1.010 to 1.030. There was a highly significant positive trend (P < 0.001) of unadjusted cadmium-in-urine with specific gravity. Conventional adjustment for specific gravity led to a highly significant negative trend (P < 0.001) of adjusted cadmium-in-urine with specific gravity, SG. An approach proposed by Vij and Howell, involving the introduction of a z coefficient, led to satisfactory adjustment. Conventional adjustment of specific gravity leads to overcompensation of the confounding effects of specific gravity. An alternative method is available and should probably be adopted when interpreting urine biological samples for all chemical substances.

Summary of measurements of employee exposure to airborne dust and fiber in sixteen facilities producing man-made mineral fibers

The results of an industry-wide study to determine the exposure of workers to man-made mineral fibers are summarized. The purpose of the study was to determine current employee exposures to airborne fibers and to utilize results to estimate past exposures. Measured exposures of workers to airborne total particulate matter and fibers are presented; samples were evaluated by phase contrast and electron microscopy. Results of the three year study, which encompassed 16 facilities and over 1500 eight hour samples, show that although there is a wide variation in concentrations of airborne fibers and particulate matter between and within the facilities surveyed, the concentrations of airborne particulate matter and fibers are generally less than 2.5 mg/m3 and 0.5 fibers/cm3, respectively. The norminal fiber size of the fibers manufactured and average airborne fiber concentration were highly correlated.

Retrospective industrial hygiene surveys

The true test of the long-term response of workers exposed to a hazardous agent is usually the epidemiological studies performed on same. This necessitates the long-term knowledge of exposure levels. Usually, the extent to which the exposures measured during recent experiences are representative of past exposures is difficult to assess as only limited historic measurements are available, and oftentimes the limited data are difficult to relate to today's measurement techniques. It is fallacious to assume that the conditions were worse in the past as it is fallacious to assume that they were better. The methodology of estimating past exposures to an agent based on industry-wide survey techniques is discussed.

The inertial behavior of fibers

The inertial deposition is given considerable credit in the deposition of inhaled particulate matter in the upper respiratory tract. A determination of the parameters governing the impaction of fibers must be the basis of evaluating the role of impaction in the respirability of fibrous dusts. The study reported here describes an experimental method of defining the inertial behavior of fibers. The results of the experiments show that the aspect ratio of the fibers plays a much more important role than hitherto considered. The results of the experimental work gave an empirical mathematical model for the prediction of the impaction of fibers from the physical properties of fibers such as density, fiber diameters and aspect ratio. In addition an equivalent diameter based on inertial properties of the fiber is developed.