Faculty Research Summary
This is a list of brief bios and faculty areas of research, listed alphabetically.
Download the Faculty Research Summary (pdf)
For the past 24 years, Dr. Balmes has been primarily interested in studying the effects of exposures to occupational and environmental agents on respiratory health, especially with regard to asthma and airway inflammation. In the Human Exposure Laboratory in the UCSF Lung Biology Center, he conducts controlled human exposure studies with sampling of respiratory tract lining fluid to characterize acute exposure-response relationships for oxidant pollutant-induced airway inflammation. He is currently funded to investigate whether common polymorphisms in xenobiotic metabolizing enzyme genes (GSTM1, GSTP1, and NQO1) are associated with increased risk of ozone-induced enhancement of airway inflammatory responses to allergens in sensitized asthmatic subjects; to determine whether exposure to ambient levels of ozone can induce acute cardiovascular effects; and to assess the acute upper airway effects of secondhand tobacco smoke.
To study the chronic effects of occupational and environmental agents on respiratory health, Dr. Balmes collaborates on epidemiological studies at UCSF and UC Berkeley. At UCSF, he has collaborated on studies of the effects of occupational exposure to respiratory tract irritants and environmental exposure to tobacco smoke on COPD outcomes (NHLBI) and the effects of environmental exposure to traffic and air pollutants on asthma outcomes (NIEHS). At UC Berkeley he has collaborated with Dr. Ira Tager to study the effects of cumulative lifetime exposure to ozone on lung function in healthy adolescents and short-term exposures to air pollutants on growth of lung function and disease severity in children with asthma in Fresno (NHLBI). With Dr. Kirk Smith, he co-leads a longitudinal study of the effects of exposure to biomass smoke on the growth of lung function in children in Guatemala (NIEHS). With Drs. Allan Smith and Craig Steinmaus, he has been investigating the role of ingested arsenic from contaminated drinking water on respiratory health in Bangladesh and Chile (NIEHS). With Dr. Michael Bates, he is investigating the effects of chronic low-level exposure to hydrogen sulfide on lung function. Dr. Balmes is PI/Director of a CDC-funded program, the UCB Center for Environmental Public Health Tracking, which is developing methods for surveillance of health outcomes that may be related to environmental exposures.
Professor Michael Bates, PhD
Co-Director, STEER Program
Dr. Bates is Adjunct Professor of Epidemiology in the School of Public Health, but based in the Division of Environmental Health Sciences. Dr Bates had a background in chemistry and toxicology before obtaining his PhD in epidemiology at Berkeley. His research focus is on the health effects of occupational and environmental exposures to chemicals. Dr Bates is Principal Investigator of a NIEHS-funded epidemiologic study being carried out in New Zealand. This study is investigating whether long-term, low-level exposures to hydrogen sulfide gas in the Rotorua geothermal area cause any health effects. With Prof Katharine Hammond he is working on an epidemiologic study in the Bay Area of whether exposures to n-hexane solvent in parts cleaners cause persistent neurological or reproductive effects, and with Prof Kirk Smith he is investigating whether exposure to indoor cooking smoke is a risk factor for tuberculosis or cataract in studies in India and Nepal.
Other areas of research interest of Dr Bates include health effects of organochlorine compounds, such as dioxins and PCBs; whether dental amalgam fillings, which contain mercury, cause any health effects; cancer risks in fire fighters, and cancer risks associated with ingestion of arsenic in drinking water.
Research Scientist Asa Bradman, PhD
Dr. Bradman is the Associate Director for the Center for Children's Environmental Health Research, a center that he helped found in 1997, and that is part of the School of Public Health. He is an environmental health scientist who focuses on environmental exposures to pregnant women and children. In this capacity he helps direct multiple biomonitoring and exposure studies investigating the relationship of environmental exposures and health in children living in the Salinas Valley, California. Dr. Bradman also leads an initiative to improve environmental health in California child care facilities. He was recently appointed by Governor Schwarzenegger to the Scientific Guidance Panel for the California Environmental Contaminant Biomonitoring Program. He also serves on the Science Advisory Council for the National Center for Healthy Homes, the California Childcare Health Program Advisory Committee, and contributed to the Exposures to Chemical Agents Working Group for the National Children's Study.
Professor Patricia Buffler, PhD
Dr. Buffler is a Professor of Epidemiology (and Dean Emerita) at the University of California (UC), Berkeley, School of Public Health. She holds an adjunct faculty position at the UC San Francisco (UCSF), School of Medicine and is an affiliate member of the UCSF Comprehensive Cancer Center. She is an internationally known cancer epidemiologist with considerable experience in epidemiologic investigations of childhood cancers and environmental exposures. For the past 16 years, her research focus has been on the epidemiology of childhood cancers. As Principal Investigator (PI), she has successfully conducted the California Childhood Leukemia Study (CCLS) since 1995. Funded by the National Institute of Environmental Health Sciences (NIEHS), the CCLS is a multi-institutional comprehensive molecular epidemiology study of childhood leukemia that has pioneered the use of a multidisciplinary approach to study the molecular, toxicologic, genetic, environmental and epidemiologic factors related to the development of childhood leukemia.
For the past two years, Dr. Buffler has also served as PI for an NIEHS-funded longitudinal study examining home exposure to carcinogens using interview data, and measuring dust levels of potentially carcinogenic compounds in the homes of childhood leukemia case and control subjects (validation/reproducibility study). This home exposures study measure levels of PCBs, PAHs and nicotine in house dust samples and evaluates the relationships between home exposures to potential carcinogens and the risks of childhood leukemia and major leukemia subtypes using corrected and uncorrected statistical approaches.
Recently, Dr. Buffler was awarded a program-project grant, jointly funded by the NIEHS and the US Environmental Protection Agency, for a new Children’s Environmental Health Center. This Center – called the Center for Interdisciplinary Research on Childhood Leukemia and the Environment (CIRCLE) -- will examine the effects of in utero and early life exposure to potentially carcinogenic chemicals present in homes. The CIRCLE includes three projects: Project 1, the Childhood Leukemia International Consortium Studies, will identify the exposures to the most relevant time periods and childhood leukemia subtypes and identify important genetic polymorphisms that can modify the association between childhood leukemia and parental tobacco smoking or home pesticide exposure by pooling data from 19 studies worldwide; Project 2, Exposure Assessment for Childhood Leukemia, will assess carcinogen exposures, based upon analysis of house dust and blood specimens, with special interest in tobacco-related contaminants, PCBs, and PBDEs; and Project 3, Prenatal Exposures, DNA Methylation, & Childhood Leukemia, will provide a clearer understanding of the association between parental smoking, pesticides, PCBs, PBDEs exposures and DNA methylation patterns in childhood leukemia, using neonatal bloods.
Professor Jack Colford, MD, MPH, PhD
(Not available Summer of 2012) Dr. Colford is a Professor of Epidemiology at the School of Public Health. He is a graduate of the Johns Hopkins School of Medicine and the UCB School of Public Health. He completed a residency in internal medicine and a fellowship in infectious diseases at UCSF and was Chief Medical Resident at Stanford. Dr. Colford teaches courses in advanced epidemiologic methods and intervention trial design and has received several teaching awards, including two awards from students at the School of Public Health.
Colford is an author of more than 65 peer-reviewed scientific publications, including numerous peer-reviewed articles on the health effects of waterborne diseases. He has received more than $19 million in research funding and was the Principal Investigator of four triple-blinded, randomized controlled trials of drinking water and health effects funded by the National Institutes of Health, the Centers for Disease Control, the Environmental Protection Agency, and the University of California. These have included large trials in the United States as well as a drinking water study in 22 villages in Bolivia. Dr. Colford was the Principal Investigator of the Mission Bay Epidemiology study about the health effects of recreational water exposure, funded by the California Regional Water Quality Control Board. Student opportunities in Dr. Colford’s group might include both the collection and analysis of epidemiological field data.
Professor Ellen A. Eisen, ScD
Dr. Eisen’s research in epidemiologic methods and applied public health bridges three fields of study—occupational health, biostatistics and epidemiology. Dr. Eisen is an adjunct faculty appointment in the Division of EHS and a member of the Graduate Groups in both EHS and Epidemiology. She also retains an adjunct professorship in Environmental and Occupational Epidemiology and Medicine Program in the Department of Environmental Health, at Harvard SPH. Dr. Eisen is the author of over 150 scientific publications related to occupational epidemiology. As a trained biostatistician, she is particularly interested in structural models that address this bias due to healthy worker survivor effect (HWSE), and yield exposure-response parameters with causal interpretation. She began her career studying pulmonary function and other nonmalignant respiratory effects of silica and cotton dust. She studies large occupational cohorts, e.g. autoworkers exposed to metalworking fluids, textile workers, and aluminum manufacturing workers, for a wide range of health outcomes. Supported by R01s from NCI and NIOSH, she trains students in the application of statistical and epidemiologic modeling methods for analyzing occupational cohort data, including nonparametric smoothing and causal inference methods. She has co-mentored students involved in occupational studies of a wide range of adverse health outcomes, including cardiovascular disease mortality, pulmonary function, cancer incidence, wrist tendonitis, delayed time to pregnancy, and cardiovascular biomarkers in relation to a wide variety of workplaces exposures.
Professor Brenda Eskenazi, PhD
Dr. Eskenazi is a Professor of Maternal and Child Health and Epidemiology at the University of California, Berkeley. She is a neuropsychologist and epidemiologist whose long-standing research interest has been the effects of toxicants including lead, solvents, environmental tobacco smoke, dioxin, and pesticides on human reproduction (both male and female) and child development. She is the Principal Investigator and Director of an NIH/EPA Center for Excellence in Children's Environmental Health Research (the "CHAMACOS" Project) which investigates the exposure pathways and health effects of pesticide exposure in farm workers and their children and develops interventions to prevent future exposure. She is also the Principal Investigator on other NIEHS-funded projects on endocrine disruption: one based in Seveso Italy investigating the reproductive health of a cohort of women exposed to high levels of dioxin, and another examining the effects of persistent and nonpersistent endocrine-disruptors on neurodevelopment. She is also the PI of a grant from EPA examining the whether children with certain PON1 genotypes are at higher risk from exposure to pesticides. Dr. Eskenazi is currently conducting a study on the effects of benzene exposure on genetic and nongenetic markers in human sperm.
Dr. Eskenazi has contributed widely to the field of children’s environmental health, including the Surgeon Generals Report on Smoking and Women’s Health, The World Health Organizations Tobacco-Free Initiatives report on Environmental Tobacco Smoke, and the United States-Vietnam Committee on the Human Health and Environmental Exposures of Agent Orange and Dioxin in Viet Nam. She served on the State of California’s Scientific Advisory Board for the Toxics Initiative (Proposition 65), which identifies chemicals as reproductive or developmental toxicants. Dr. Eskenazi has served on the Scientific Advisory Board of the Children’s Health Environmental Coalition and on the Study Design Working Group of the National Children’s Study. She is currently a member of the Expert Committee for the Stockholm Convention.
Dr. Hammond studies the exposures of people to toxic air contaminants. These might be environmental exposures such as secondhand smoke or occupational exposures. This research is usually coupled with studies of the health effects associated with these exposures. Some members of her team, which consists of students and staff, do chemistry laboratory work while others primarily work on evaluation of the data, using computers and statistical programs to evaluate and model exposures. Students would learn the methods associated with these studies under the direction of Professor Hammond.
She directs a laboratory, which contains equipment to sample the air and also chemistry instrumentation to analyze the samples collected. Several computers are available in the laboratory with software to conduct these analyses, including geographic information system software and statistical packages. Student projects could include any of the following:
- Evaluate data on allergen or endotoxin levels on dust collected from the beds of children with asthma
- Collect pine needle samples to evaluate airborne levels of polycyclic aromatic hydrocarbons (PAHs) and analyze samples using liquid chromatography and gas chromatography/mass spectrometry
- Develop methods to distinguish wood smoke from automobile exhaust
- Analyze samples of coal from China for PAHs and develop models to estimate exposure to coal emissions and PAHs in the past
- Evaluate the exposure of asthmatic children in various states across the U.S. as a function of smoke free environmental laws in those states
- Develop retrospective estimates of secondhand smoke concentrations on airplanes.
Professor Nina Holland, PhD
Dr. Holland is an adjunct professor at the School of Public Health and a director of the School's bio-repository and the Children's Environmental Health Laboratory. She has a background in genetics with extensive experience in molecular epidemiology, human cytogenetics, reproductive toxicology and biobanking. Dr. Holland has an international reputation for her research in the area of biomarkers of effect, and has conducted a number of studies on functional genetics and analysis of genetic susceptibility to environmental factors and predisposition to disease. Her main scientific interest is in molecular epidemiology of children's environmental health. She has organized and chaired several sessions on this topic at national and international meetings.
Currently, Dr. Holland is principal investigator on a study investigating functional genomics of paraoxonase in the cohort of Latino mothers and children. This longitudinal birth cohort has been followed by Dr. Holland in conjunction with Dr. Brenda Eskenazi, for many years. In addition, Dr. Holland is assessing the effects of GSTM1/T1 and multiple polymorphisms on ozone-induced allergic airway inflammation, as well as health effects and biomarkers in Guatemalan children exposed to biofuel indoor pollution, in conjunction with Professors Kirk Smith, Katharine Hammond, and John Balmes. Drs. Holland and Eskenazi also recently completed a study evaluating endocrine disrupting effects of organochlorine pesticides on Latino children and mothers in agricultural communities. There is major student participation in Dr. Holland's laboratory with as many as seven undergraduates, three-four master's and doctoral students working concurrently. Students undergo training in an active lab environment where undergraduates work as team members with the graduate students under the direction of Dr. Holland and her research team. Undergraduate students receive degree credit through an independent study mechanism, present at the lab seminars, and complete their honors projects.
Professor Michael Jerret, PhD
Dr. Jerrett, received his PhD in geography from the University of Toronto (Canada), and is an associate professor in the Division of Environmental Health Science, School of Public Health, University of California, Berkeley. For the past 14 years, Dr. Jerrett has researched how to characterize population exposures to air pollution, what the social distribution of air pollution is among different groups (e.g., poor vs. wealthy), and how to assess the health effects from air pollution exposures. Building on expertise in Health Geography, Geographic Information Science, and Spatial Analysis, Dr. Jerrett assesses the role of the built environment on numerous health risks and outcomes. His topical areas of focus are (a) air pollution exposure modeling and health effects assessment; (b) obesity and the built environment (i.e., how the built landscape influences physical activity and food intake); and (c) the social distribution of environmental exposures. He has published some of the most widely cited studies on air pollution health effects, social susceptibility to environmental risks, and environmental inequality. Dr. Jerrett recently co-wrote “Traffic-Related Air Pollution: A Critical Review of the Literature on Emissions, Exposure, and Health Effects” published by the Health Effects Institute. This report is the most comprehensive and systematic review to date of the scientific literature on emissions, exposure, and health effects from traffic-related air pollution. The United States National Academy of Science recently recognized Dr. Jerrett’s accomplishments by appointing him to the Committee on “Future of Exposure Assessment in the 21st Century.”
Dr. McKone’s research group explores and quantifies how human exposure comes about, how exposure relates to health detriment, and how precisely these links can be quantified for a number of important pollutants. To pursue this effort, the research team has worked on:
- Defining and modeling chemical transport and transformation in the environment;
- Biotransfer and bioconcentration;
- Measuring and modeling dermal and inhalation exposures to contaminants in tap water and household dust;
- Chemical mass transport at inter-media contacts such as air/water, air/soil, air/vegetation, skin/water, etc.
- Assessing model uncertainty and reliability
- Public health and ecological impacts of energy, industrial, and agricultural systems
Dr. McKone has research facilities and equipment at both the University of California Berkeley and at the Lawrence Berkeley National Laboratory (LBNL). At these two institutions, the research team devotes much of its research to the development of probabilistic, multi-pathway, multimedia human and exposure/impact models. This group has two operating environmental chamber facilities designed for investigating emissions of pollutants from indoor sources under simulated, controlled indoor environmental conditions. Other relevant facilities at LBNL and UC Berkeley available to Dr. McKone include the Gas Chromatography/Mass Spectrometry/Data Analysis System and Laboratory; the Organic Chemical Analysis Laboratory, and the Aerosol Research Laboratory.
Professor Mark Nicas, PhD, MPH, CIH
Dr. Nicas is adjunct professor of environmental health sciences and director of the Industrial Hygiene Program. He advises one PhD student, and 8 MPH students. He is an active researcher and has 56 publications in the peer-reviewed environmental health literature. His current work focuses on two related areas. First, he develops mathematical models of contaminant emission rates and transport-and-fate in indoor air environments. Second, he is engaged in microbial risk assessment research, and is interested in the potential interaction of different exposure pathways for the same pathogen--for example, emission into air due to coughing, leading to pathogen deposition onto surfaces, thereby permitting hand-to-surface-to-mucous-membrane transmission.
Undergraduate students working with Professor Nicas would have the opportunity to participate in research related to chemical or microbial exposure assessment. Depending on the research project being conducted at the time of participation, the student might be involved in making exposure measurements; learning how to formulate a mathematical model; writing computer code; or performing a critical literature review.
Research Scientist, Dr. Amanda Northcross
Co-Director, STEER Program
Dr. Northcross works with both Dr. Kathie Hammond and Dr. Kirk Smith. Her research is focused on measuring exposures to airborne contaminants. With Dr. Smith she works to quantify exposures to wood smoke from inefficient cookstoves as a part of a longitudinal cookstove intervention study in the rural highlands of Guatemala. The Smith research group is also developing a low cost particle monitor with a measurable concentration range that will be functional both in the United States as well as in homes using solid fuel for cooking which have orders of magnitude higher concentrations. With Prof. Hammond, Dr. Northcross’ work is focused on the chemical analysis of airborne particles. She is working to develop a method to measure reactive oxidative species in particles, which are hypothesized to be one of the key actors in the mechanism of injury for airborne particles from many sources including cigarette smoke, diesel smoke and wood smoke to name a few.
A STEER intern will gain experience using aerosol measurement instruments and will assist with chemical analysis of airborne samples.
(Not available Summer of 2012) Dr. Rappaport is active in research involving both environmental and biological monitoring. His current research focuses on development and application of biomarkers of exposure to toxic chemicals arising from exposures to both exogenous and endogenous sources. Dr. Rappaport has also published extensively in areas related to the assessment of long-term exposures to chemicals for purposes of controlling workplace hazards and of investigating exposure-response relationships. The principal opportunities for research experiences for students in this program are laboratory-based, relating to his biomarker work.
Research Scientist, Megan Schwarzman, MD, MPH
In the Program in Green Chemistry and Chemicals Policy, we work at the nexus of the environmental health sciences and public policy to advance the field of green chemistry: the design, manufacture and use of chemicals and products to reduce or eliminate adverse affects on human health and ecosystems. We work within the University, as well as with community groups and state and federal government to advance chemicals policy and address the implications for human health and the environment of the production, use and disposal of chemicals and products. Our work focuses specifically on: occupational health, endocrine disruption, sustainable production, exposure assessment, reproductive health, the cumulative impacts of multiple stressors on ecosystem health, and European Union chemicals policy. (More at: http://coeh.berkeley.edu/greenchemistry)
STEER students would participate in elements of our daily work as well as conducting a research project on a specific topic. Although we work with students to tailor a project to their interests, possible projects could address the following topics: Climate Change and Green Chemistry, Shaping State Policy: Reviewing Assessment Tools (life cycle assessment, chemical prioritization, or alternatives assessment).
Professor Edmund Seto, PhD
Dr. Seto is Associate Adjunct Professor of Environmental Health Sciences and director of the UC Berkeley Health Impact Group (UCBHIG) and Public Health Assisting Smart Technologies (PHAST) group. Dr. Seto's expertise is in measuring and modeling individual exposures to environmental hazards, including exposures to infectious agents and air, water, and noise pollution. His group, which consists of PhD, Masters, and Undergraduate students, conducts research on the health implications of proposed policies, plans, projects, and technologies. His research is funded by the National Institutes of Health, Centers for Disease Control, and through partnerships with industry leaders, including Nokia, Qualcomm, LG, and Verizon.
Dr. Seto is looking for a highly motivated and creative undergraduate researcher to work with his group to help develop and test a novel personal environmental exposure monitor that can be easily built from inexpensive sensors, and which would greatly enable community-based participatory environmental health studies.
Professor Kirk R. Smith, PhD
Prof. Smith is Professor of Global Environmental Health and is also founder and coordinator of the campus-wide Masters Program in Global Health and Environment. Previously, he was founder and head of the Energy Program of the East-West Center in Honolulu before moving to Berkeley in 1995. He serves on a number of national and international scientific advisory committees including the Global Energy Assessment, National Research Council’s Board on Atmospheric Science and Climate, the Executive Committee for WHO Air Quality Guidelines, and the International Comparative Risk Assessment. He participated, along with many other scientists, in the Intergovernmental Panel on Climate Change’s 3rd and 4th assessments and is Convening Lead Author for Climate and Health for the 5th Assessment. Prof. Smith’s research focuses on environmental and health issues in developing countries, particularly those related to health-damaging and climate-changing air pollution from household energy use, and includes field measurement and health-effects studies in India, China, Nepal, Mexico, and Guatemala as well as development and application of tools for international policy assessments. He also develops and deploys small, smart, and cheap microchip-based monitors for use in household air pollution studies.
Professor Martyn Smith, PhD
Dr. Smith is a professor of toxicology and conducts research aimed at finding the causes of blood cancers (e.g., leukemia and lymphoma) in adults and children. Dr. Smith uses a molecular epidemiology approach using state of the art biomarkers and cultured stem and progenitor cell model systems. He studies benzene as a model because it is an established cause of blood diseases. In addition to the work described above, Dr. Smith aims to develop advanced methods from the detection, quantification, and remediation of human exposure to toxic substances. Dr. Smith's laboratory facilities at UCB are well-located and support his team of post-doctoral researchers, graduate and undergraduate students.
Professor Robert Spear, PhD
Dr. Spear is an engineer with research interests in the assessment and quantification of human exposures to toxic and infectious agents in the environment. His early work concerned the exposure of agricultural workers to pesticides. In recent years his research has concerned the use of mathematical and statistical techniques in the assessment and control of both workplace and community exposures. His current work, in collaboration with colleagues at UCB and at the Sichuan Institute of Parasitic Disease in China, focuses on environmental determinants of the incidence and control of the parasitic disease schistosomiasis. His group has pioneered the use of GIS/GPS technology for mapping and geo-referencing field data, and they have utilized remote sensing technology for the assessment of snail habitat and other landscape features relevant to defining the scale of control strategies. These data and site-specific information from field surveys are integrated through mathematical models that allow both tracking and forecasting of disease intensity over time. Recent work has focused on defining the internal potential of a village to sustain disease transmission and the spatial inter-connectedness of the disease transmission process between villages.
Opportunities for high school and undergraduate students potentially relate to data collection in the field in China and methods for the interpretation and analysis of these field data in Berkeley. A staff of full-time researchers and graduate students are available and experienced in mentoring and supervising undergraduates in research experiences.
Dr. Zhang is an Associate Adjunct Professor of Toxicology in the Division of Environmental Health Sciences (EHS), School of Public Health at the University of California, Berkeley. For the past two decades, her research has focused on understanding the molecular mechanisms of bone marrow toxicity caused by benzene (BZ) and other toxic chemicals including butadiene (BD), formaldehyde (FA), tricholoroethylene (TCE) and arsenic (As). Dr. Zhang’s investigations have mainly involved the detection of biomarkers associated with these chemical exposures in molecular epidemiological studies conducted with national and international collaborators. Her group investigated specific chromosomal aneuploidies and rearrangements in many of these studies, as well as in mature and progenitor human cells in vitro by a molecular cytogenetic method named FISH (fluorescence in situ hybridization). More recently, she has developed and applied the innovative OctoChrome FISH method which simultaneously detects specific rearrangements of all 24 human chromosomes, including common genetic changes associated with leukemia and/or lymphoma. In order to identify additional biomarkers and disease-related mechanisms associated with these chemical exposures, Dr. Zhang and her group have developed and continue to employ many high-throughput technologies, such as single-cell genetic analysis (SCGA) and array-based toxicogenomic (genomics, transcriptomics, proteomics, and metabolomics) and epigenomic (DNA-methylation, histone modification, and microRNA expression) tools. These advanced omic methodologies and RNAi (RNA interference) are also applied to in vitro human cell culture studies of chemical exposure. Besides her long-term involvement and contributions to the Northern California Childhood Leukemia Study (NCCLS), Dr. Zhang has been a co-project leader and/or co-principal investigator in the Center for Interdisciplinary Research on Childhood Leukemia and the Environment (CIRCLE), the Superfund Basic Research Program (SBRP) and the Center for Exposure Biology (CEB) at Berkeley. Building on her concern for the recent increase in China’s environment-related health issues, she has, and actively continues to forge connections with leading Chinese institutions to advance research into this crisis.
© 2008-2012, Center for Occupational and Environmental Health, UC Berkeley