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Organization and Management of a Laser Safety Program
Published in Kenneth L. Miller, Handbook of Management of Radiation Protection Programs, 2020
The American Conference of Governmental Industrial Hygienists (ACGIH) has issued threshold limit values (TLVs) for noise levels.33 Ear protection should be worn when an individual may be exposed to noise levels above 90 dB for 8 hr a day. For periods less than 15 min, permissible noise levels can be as high as 115 dB.
Critical Organs, Critical Concentrations, and Whole Body Dose-Response Relationships
Published in Lars Friberg, Tord Kjellström, Carl-Gustaf Elinder, Gunnar F. Nordberg, Cadmium and Health: A Toxicological and Epidemiological Appraisal, 2019
Occupational standards [threshold limit values (TLV)] have been set in a number of countries.10 Most of these countries use the TLV set by the American Conference of Governmental Industrial Hygienists at 50 μg/m3. Finland has a TLV of 20 μg/m3 for dust and 10 μg/m3 for fume. Sweden has a TLV of 50 μg/m3 for total dust, 20 μg/m3 for respirable dust and fume in existing workplaces, and 10 μg/m3 for respirable dust and fume in new workplaces.
Statistical Change-Point Analysis
Published in Albert Vexler, Alan D. Hutson, Xiwei Chen, Statistical Testing Strategies in the Health Sciences, 2017
Albert Vexler, Alan D. Hutson, Xiwei Chen
Gurevich and Vexler (2005) considered generalized maximum likelihood asymptotic power one tests that aim to detect a change point in logistic regression when the alternative specifies that a change occurred in parameters of the model. A guaranteed nonasymptotic upper bound for the significance level of each of the tests is presented. For cases in which the test supports the conclusion that there was a change point, the authors proposed a maximum likelihood estimator of that point and present results regarding the asymptotic properties of the estimator. An important field of application of this approach is occupational medicine, where for a lot of chemical compounds and other agents, so-called threshold limit values (TLVs) are specified. The authors demonstrated applications of the test and the maximum likelihood estimation of the change point using an actual problem that was encountered with real data.
Toxicological assessment of electronic cigarette vaping: an emerging threat to force health, readiness and resilience in the U.S. Army
Published in Drug and Chemical Toxicology, 2022
Marc A. Williams, Gunda Reddy, Michael J. Quinn, Amy Millikan Bell
As discussed above, a marked concern is poor appreciation of the potential health effects of the components that are found in e-cigs but not in conventional cigarettes. For example, glycols (propylene glycol and glycerin) are major components of e-cigs. An internal technical report that was specifically commissioned by users and vendors of e-cigs concluded that the estimated exposure levels to glycols approached threshold-limit values. This conclusion raised concerns that the threshold limit values were derived from uncertainty rather than formal knowledge (Burstyn 2013, Pissinger and Dossing 2014). This issue is made more complex by a poor understanding of the consequences of e-cig users’ switching among different e-cig brands and devices. This habit exposes the e-cig user to a myriad of more complex exposures, unlike those of conventional cigarette users, who tend to remain brand loyal. Furthermore, there are likely health effects from exposure to glycol and other contaminants or toxicants found in the various brands of e-cigs, as discussed above. Although many of these identified substances were detected at very low concentrations, e-cig use remains an intense and chronic process from a device that is highly efficient at delivering nicotine and other toxicants/contaminants to the lungs of the e-cig user.
Occupational heat strain in outdoor workers: A comprehensive review and meta-analysis
Published in Temperature, 2022
Leonidas G. Ioannou, Josh Foster, Nathan B. Morris, Jacob F. Piil, George Havenith, Igor B. Mekjavic, Glen P. Kenny, Lars Nybo, Andreas D. Flouris
The International Organization for Standardization (ISO), the American Conference of Governmental Industrial Hygienists (ACGIH), and the National Institute for Occupational Safety and Health (NIOSH) have each published Threshold Limit Values (TLVs) relating to safe work durations at different levels of WBGT exposure. Safe work durations are expressed as the percent of work time that should be spent working or resting (typically in a 1-hour bout). The advice can be further modified based on expected work intensity (expressed in Watts or Watts per square meter of body surface area) and clothing [122]. Higher work rates and clothing insulation values necessitate a reduction in safe allowable work durations for a given WBGT. The advice is intended to limit core temperature of an average group of workers from exceeding 38°C, such that those at the upper end of the distribution would be prevented from exceeding 41°C, a risk for heat stroke development. The advice from the ACGIH and ISO standard have been used to form predictions of labor capacity [123,124]. For example, Dunne and colleagues [123] combine ACGIH TLVs for light, moderate and heavy labor into a single metric, such that % workability can be determined against the same WBGT axis along a continuum ranging from 25 to 32.2°C. A similar approach has been used by Bröde and colleagues [124], who compared results using the TLVs from ISO:7243 or NIOSH.
Effects of work schedule and period of exposure on changes in urinary chromium and nickel excretion among rotating shift workers in a stainless-steel plant
Published in Chronobiology International, 2019
Hiroaki Itoh, Rui-Sheng Wang, Syou Maki, Qiao Niu, Huizhen Shang, Yougong Su, Zuquan Weng, Hiroyuki Saito, Nobuhiko Miura, Masaya Takahashi
Therefore, based on the findings reported herein, the use of a single reference value, such as threshold limit values, for permissible exposure levels of metals across shifts should not be appropriate, especially for shift workers who are exposed to metals at different times of day. Currently, a permissible exposure level of chromium by the American Conference of Governmental Industrial Hygienists (ACGIH) is based on the level in spot urine samples (25 μg/L at the end of a shift, at the end of the workweek) (CDC 2013). With a time-dependent variation in urinary metal excretion, permissible exposure values need to be adjusted according to work schedules or with the consideration of the time phase when the excretion is least. In other words, a regulator such as ACGIH would be needed to set work shift-specific permissible urinary excretion levels of metals. Evening shift may also be the time when the metals are likely to transfer to an organ (Further, rotating shift work itself may increase the transfer). Consequently, setting a single flat value of threshold limit values or biological exposure indices all day and night would not always be appropriate, particularly among rotating shift workers. A similar concept has been presented in Smolensky et al. (2017).