Abstract  These guidelines revise and replace the U.S. Environmental Protection Agency’s (EPA’s, or the Agency’s) Guidelines for Carcinogen Risk Assessment, published in 51 FR 33992, September 24, 1986 (U.S. EPA, 1986a) and the 1999 interim final guidelines (U.S. EPA, 1999a; see U.S. EPA 2001b). They provide EPA staff with guidance for developing and using risk assessments. They also provide basic information to the public about the Agency's risk assessment methods.

Abstract  The Guidelines for Exposure Assessment describe the general concepts of exposure assessment including definitions and associated units, and by providing guidance on the planning and conducting of an exposure assessment. Guidance is also provided on presenting the results of the exposure assessment and characterizing uncertainty. Although these Guidelines focus on exposures of humans to chemical substances, much of the guidance also pertains to assessing wildlife exposure to chemicals, or human exposures to biological, noise, or radiological agents. The Guidelines include a glossary which helps standardize terminology used by the Agency in exposure assessment. They emphasize that exposure assessments done as part of a risk assessment need to consider the hazard identification and dose-response parts of the risk assessment in the planning stages of the exposure assessment so that these three parts can be smoothly integrated into the risk characterization. The Guidelines discuss and reference a number of approaches and tools for exposure assessment, along with discussion of their appropriate use. The Guidelines also stress that exposure estimates along with supporting information will be fully presented in Agency risk assessment documents, and that Agency scientists will identify the strengths and weaknesses of each assessment by describing uncertainties, assumptions, and limitations, as well as the scientific basis and rationale for each assessment.

Abstract  1-Bromopropane (1-BP; CAS number 106-94-5), also known as n-propyl bromide, is a halogenated short-chain alkane used as an organic solvent with numerous commercial and industrial applications, including garment dry cleaning and vapor degreasing of metals. The purpose of this study was to determine the dermal absorption characteristics and corrosivity of 1-BP. Heat-separated human epidermal membranes were mounted on static diffusion cells. Different exposure scenarios were studied (infinite dose, finite dose, and transient exposure) using neat 1-BP and saturated aqueous solution as donor. Steady-state fluxes for infinite-dose neat 1-BP exposure averaged 625 to 960 μg cm(-2) h(-1). The finite-dose (10 μl/cm(2) = 13.5 mg/cm(2)) unoccluded donor resulted in penetration of <0.2% of the applied dose (22 μg/cm(2)). A 10-min transient exposure to infinite dose resulted in total penetration of 179 μg/cm(2). Steady-state 1-BP fluxes from neat application of a commercial dry cleaning solvent were similar (441 to 722 μg cm(-2) h(-1)). The permeability coefficient of 1-BP in water vehicle was 0.257 ± 0.141 cm/h. The absorption potential of 1-BP following dermal exposure is dependent upon the type and duration of exposure. Donor losses due to evaporation were approximately 500-fold greater than dermal absorption flux; evaporation flux was 420 mg cm(-2) h(-1). 1-BP is cytotoxic but not corrosive, based on results from a cultured reconstructed human epidermal model (EpiDerm Skin Corrosivity Test).

Abstract  p-Chloro-o-toluidine and its hydrochloride salt are reasonably anticipated to be human carcinogens based on limited evidence of carcinogenicity from studies in humans and evidence of carcinogenicity from studies in experimental animals.

Abstract  This draft risk evaluation for 1,4-dioxane was performed in accordance with the Frank R. Lautenberg Chemical Safety for the 21st Century Act and is being disseminated for public comment and peer review. The Frank R. Lautenberg Chemical Safety for the 21st Century Act amended the Toxic Substances Control Act, the Nation’s primary chemicals management law, in June 2016. As per EPA’s final rule, Procedures for Chemical Risk Evaluation Under the Amended Toxic Substances Control Act (82 FR 33726), EPA is taking comment on this draft, and will also obtain peer review on this draft risk evaluation for 1,4-dioxane. All conclusions, findings, and determinations in this document are preliminary and subject to comment. The final risk evaluation may change in response to public comments received on the draft risk evaluation and/or in response to peer review, which itself may be informed by public comments.

Abstract  A method involving classification of employee job tasks into exposure zones is proposed to guide the industrial hygienist in assigning personal samples to employees in a facility. Workers are assigned to an exposure zone on the basis of similar profiles of chemical exposures, ventilation characteristics, and job tasks. Two facilities are used to illustrate the power of the exposure zone method to reduce the number of required samples while increasing the confidence of identifying workers at high risk. Details of the zoning and calculation procedures are described in detail.

Abstract  Abstract: Exposure to 1,4-dioxane from the atmosphere around high-emission plants and from consumer products used in daily life that contain the substance may have adverse health effects; however, its emission into the atmosphere is not regulated. In this study, the health risk posed by 1,4-dioxane is assessed to investigate whether measures should be undertaken to reduce exposure to 1,4-dioxane. The notion of the margin of exposure (MOE), given by the ratio of no observed adverse effect level (NOAEL) to actual or projected exposure level, is used to assess risk. In exposure assessment, two types of exposure channel are considered: (a) the use of consumer products that contain 1,4-dioxane and (b) the inhalation of air around high-emission plants. To estimate exposure via channel (a), we measured the concentration of 1,4-dioxane in consumer products and estimated the interindividual variability of exposure by Monte Carlo simulation that reflects the measured data. To estimate exposure via channel (b), we employed a local-level atmospheric dispersion model to estimate the concentration of 1,4-dioxane immediately around high-emission plants. For hazard assessment, we derived the inhalatory and oral NOAELs for liver adenomas and carcinomas and the uncertainty factor. The results suggest that measures are not needed to reduce exposure to 1,4-dioxane from consumer products. As for inhalation exposure around high-emission plants, some residents may be exposed to health risks if certain conservative analytical conditions are assumed. Even in this case, we conclude that it is not necessary for Plant A to stop the use of 1,4-dioxane immediately and that medium- to long-term emission reduction measures should be sufficient. nmental sciences : an international journal of environmental physiology and toxicology e field[29]: 1,4-Dioxane

Abstract  Fragranced consumer products-such as air fresheners, laundry supplies, personal care products, and cleaners-are widely used in homes, businesses, institutions, and public places. While prevalent, these products can contain chemicals that are not disclosed to the public through product labels or material safety data sheets (MSDSs). What are some of these chemicals and what limits their disclosure? This article investigates these questions. and brings new pieces of evidence to the science, health, and policy puzzle. Results from a regulatory analysis, coupled with a chemical analysis of six best-selling products (three air fresheners and three laundry supplies), provide several findings. First. no law in the U.S. requires disclosure of all chemical ingredients in consumer products or in fragrances. Second, in these six products, nearly 100 volatile organic compounds (VOCs) were identified, but none of the VOCs were listed on any product label, and one was listed on one MSDS. Third. of these identified VOCs. ten are regulated as toxic or hazardous under federal laws, with three (acetaldehyde, chloromethane, and 1,4-dioxane) classified as Hazardous Air Pollutants (HAPs). Results point to a need for improved understanding of product constituents and mechanisms between exposures and effects. (C) 2008 Elsevier Inc. All rights reserved.

Abstract  U.S. Department of Health and Human Services released the 14th Report on Carcinogens November 2016. The RoC is a congressionally mandated, science-based, public health document that NTP prepares for the HHS Secretary. This cumulative report currently includes 248 listings of agents, substances, mixtures, and exposure circumstances that are known or reasonably anticipated to cause cancer in humans.