Peter J. Baxter

Hunter's diseases of occupations

PART ONE - GENERAL CONSIDERATIONS Section One: History and Development of Occupational Medicine Donald Hunter and the history of occupational health: precedents and perspectives Joseph Melling and Tim Carter The changing face of occupational diseases Peter J Baxter, Tar-Ching Aw, Anne Cockcroft, Paul Durrington and J Malcolm Harrington Section Two: Diagnosis of Occupational Disease The occupational history Tar-Ching Aw Occupational exposure to hazardous substances John W Cherrie and Sean Semple Biological monitoring John Cocker and Howard J Mason Section Three: Extent and Attribution of Occupational Disease Epidemiological methods and evidence-based occupational medicine David Coggon Attribution of disease Anthony Newman Taylor and David Coggon Compensation schemes Anthony Newman Taylor and David Walters Section Four: Legal Issues Medicolegal reports and the role of the expert witness Diana M Kloss PART TWO - DISEASES ASSOCIATED WITH CHEMICAL AGENTS Section One: Occupational Toxicology Occupational toxicology: general principles Peter G Blain and Robert D Jefferson Risks and hazards in occupational and environmental exposures Robert L Maynard Section Two: Metals Introduction Tar-Ching Aw Aluminium Perrine Hoet Antimony Malcolm R Sim Arsenic Malcolm R Sim Beryllium Lee S Newman and Holly M Christensen Cadmium Perrine Hoet Chromium Tom Sorahan Cobalt Perrine Hoet Copper Peter Aggett Gold Peter Linnett Iron Peter Aggett Lead Peter J Baxter and Hideki Igisu Magnesium Peter Aggett Manganese Grant McMillan and Finlay D Dick Mercury Peter J Baxter and Hideki Igisu Molybdenum Malcolm R Sim Nickel Tom Sorahan Phosphorus Malcolm R Sim Platinum group metals Peter Linnett Polonium Iain Blair Silver Peter Linnett Thallium Hideki Igisu and Tar-Ching Aw Tin Tar-Ching Aw and Hideki Igisu Tungsten Perrine Hoet Uranium Iain Blair Vanadium Finlay D Dick Zinc Peter Aggett Section Three: Gases Gases Peter J Baxter Reactive airways dysfunction syndrome and irritant-induced asthma Jon G Ayres Deliberate use of chemicals in warfare and by terrorists Robert L Maynard Section Four: Other Chemical Exposures Organic chemicals Tiina Santonen, Antero Aitio and Harri Vainio Pesticides and other agrochemicals Ian Brown, Annalisa Chiodini, Chiara Somaruga and Claudio Colosio Welding Grant McMillan The semiconductor industry David Koh and Judy Sng PART THREE - DISEASES ASSOCIATED WITH PHYSICAL AGENTS Section One: Noise Sound, noise and the ear Richard T Ramsden and Shakeel R Saeed Section Two: Vibration Hand-arm vibration syndrome Ian J Lawson, Frank Burke, Kenneth L McGeoch, Tohr Nilsson and George Proud Whole body vibration Massimo Bovenzi and Keith Palmer Section Three: Heat and Cold Heat and cold E Howard N Oakley Section Four: Barometric Pressure Diving and work at increased pressure Stephen Watt and Andrew Colvin Working at high altitude Peter JG Forster Flying and spaceflight Mike Gibson, David Gradwell and Alyson Calder Section Five: Radiation Ionizing radiations Chris Sharp and Fred A Mettler Jr Non-ionizing radiation and the eye Michael E Boulton and David H Sliney Extremely low frequency electric and magnetic fields Leeka Kheifets and Gabor Mezei Radiofrequency fields Gabor Mezei and Leeka Kheifets PART FOUR - DISEASES RELATED TO ERGONOMIC AND MECHANICAL FACTORS Section One: The Musculoskeletal System Repeated movements and repeated trauma affecting the musculoskeletal system Cyrus Cooper and Keith Palmer Section Two: Back and Spinal Pain Occupational back pain Jos H Verbeek and Frederieke Schaafsma PART FIVE - OCCUPATION AND TRANSMISSIBLE DISEASES Section One: Occupational Infections Occupational infections Julia Heptonstall and Anne Cockcroft Zoonoses Alastair Miller and Julia Heptonstall Section Two: Bioterrorism and Biotechnology Bioterrorism Julia Heptonstall Genetic modification and biotechnology David Roomes PART SIX - WORK AND MENTAL HEALTH Section One: Work and Stress Introduction to work and stress Peter Baxter, Tar-Ching Aw and Anne Cockcroft Work, stress and sickness absence: a psychosocial perspective Maurice Lipsedge and Michael Calnan Mental health at work: psychological interventions Adrian Neal Section Two: Work and Psychiatric Disorder Work and psychiatric disorder: an evidence-based approach Nick Glozier, Max Henderson, Neil Greenberg and Simon Overland Section Three: Substance Abuse Substance abuse and the workplace Jonathan D Chick PART SEVEN - RESPIRATORY DISORDERS Section One: General Issues Imaging in occupational lung disease Paul M Taylor Work and chronic air flow limitation David J Hendrick Health effects of ultrafine/nanoparticles Ken Donaldson, Robert J Aitken, Jon G Ayres, Brian G Miller and C Lang Tran Health effects related to non-industrial workplace indoor environments Jouni JK Jaakkola and Maritta S Jaakkola Section Two: Organic Dust Diseases Occupational asthma Paul Cullinan and Anthony Newman Taylor Byssinosis and other cotton-related diseases CAC Pickering and Robert Niven Extrinsic allergic alveolitis Paul Cullinan and Anthony Newman Taylor Section Three: Inorganic Dust Diseases Inorganic dusts: general aspects Anne Cockcroft Asbestos and asbestos-related diseases David Weill and Anne Cockcroft Epidemiology of asbestos-related diseases Robin M Rudd Other fibrous mineral dusts Anne Cockcroft Silica and silica-related diseases Anne Cockcroft Epidemiology of silica-related disease Kyle Steenland Other non-fibrous mineral dusts Anne Cockcroft Metal dusts and fumes Benoit Nemery Berylliosis Holly M Christensen and Lee S Newman PART EIGHT - OTHER EFFECTS OF WORKPLACE EXPOSURES Section One: Occupational Diseases of the Skin Occupational diseases of the skin John English and Jason Williams Section Two: Occupational Cancers Occupational cancer: epidemiology, biological mechanisms and biomarkers Manolis Kogevinas, J Malcolm Harrington and Roel Vermeulen Section Three: Other Systemic Effects Nephrotoxic effects of workplace exposures Rema Saxena, Pearl Pai and Gordon M Bell Neurotoxic effects of workplace exposures Michael J Aminoff and Marcello Lotti Hepatotoxic effects of workplace exposure Thomas W Warnes and Alexander Smith Workplace exposures and reproductive health Jens Peter Bonde Haemopoietic effects of workplace exposures: anaemias, leukaemias and lymphomas Edward Gordon-Smith, Anthony Yardley-Jones and Atherton Gray Section Four: Shift Work Shift work and extended hours of work Giovanni Costa, Simon Folkard and J Malcolm Harrington

Health hazards and disaster potential of ground gas emissions at Furnas volcano, São Miguel, Azores

A health hazard assessment of exposure to soil gases (carbon dioxide and radon) was undertaken in the village of Furnas, located in the caldera of an active volcano. A soil survey to map the area of soil gas flow was undertaken, gas emissions were monitored at fumaroles and in eight houses, and a preliminary radon survey of 23 houses in the main anomaly area was performed. Potential volcanic sources of toxic contamination of air, food, and water were also investigated, and ambient air quality was evaluated. About one-third (41 ha) of the houses were located in areas of elevated carbon dioxide soil degassing. Unventilated, confined spaces in some houses contained levels of carbon dioxide which could cause asphyxiation. Mean indoor radon levels exceeded UK and US action levels in the winter months. A tenfold increase in radon levels in one house over 2 h indicated that large and potentially lethal surges of carbon dioxide could occur without warning. Toxic exposures from the gaseous emissions and from contamination of soil and water were minimal, but sulphur dioxide levels were mildly elevated close to fumaroles. In contrast, evidence of dental fluorosis was manifested in the population of the nearby fishing village of Ribeira Quente where drinking water in the past had contained elevated levels of fluoride. The disaster potential of volcanic carbon dioxide in the area could also be associated with the hydrothermal system storing dissolved carbon dioxide beneath the village. Felt, or unfelt, seismic activity, or magma unrest, especially with a reawakening of explosive volcanic activity (30% probability in the next 100 years) could result in an increase in gas flow or even a gas burst from the hydrothermal system. A survey of all houses in Furnas is advised as structural measures to prevent the ingress of soil gases, including radon, were needed in some of the study houses. Evaluations of the human hazards of volcanic gases should be undertaken in all settlements in volcanic and hydrothermal areas associated with soil gas emissions.

Evidence-based volcanology: application to eruption crises

Abstract The way in which strands of uncertain volcanological evidence can be used for decision-making, and the weight that should be given them, is a problem requiring formulation in terms of the logical principles of Evidence Science. The basic ideas are outlined using the explosion at Galeras volcano in Colombia in January 1993 as an example. Our retrospective analysis suggests that if a robust precautionary appraisal had been made of the circumstances in which distinctive tornillo signals were detected at Galeras, those events might have been construed as stronger precursory evidence for imminent explosive activity than were the indications for quiescence, given by the absence of other warning traits. However, whilst visits to the crater might have been recognised as involving elevated risk if this form of analysis had been applied to the situation in January 1993, a traditional scientific consideration of the available information was likely to have provided a neutral assessment of short-term risk levels. We use these inferences not to criticise interpretations or decisions made at the time, but to illustrate how a structured, evidence-based analysis procedure might have provided a different perspective to that derived from the conventional scientific standpoint. We advocate a formalism that may aid such decision-making in future: graphical Bayesian Belief Networks are introduced as a tool for performing the necessary numerical procedures. With this approach, Evidence Science concepts can be incorporated rationally, efficiently and reliably into decision support during volcanic crises.

Building vulnerability and human casualty estimation for a pyroclastic flow: a model and its application to Vesuvius

Abstract Pyroclastic flows clearly present a serious threat to life for the inhabitants of settlements on the slopes of volcanoes with a history of explosive eruptions; but it is increasingly realised that buildings can provide a measure of protection to occupants trapped by such flows. One important example is Vesuvius, whose eruption history includes many events which were lethal for the inhabitants of the neighbouring Vesuvian villages. Recent computational fluid dynamics computer modelling for Vesuvius [Todesco et al., Bull. Volcanol. 64 (2002) 155–177] has enabled a realistic picture of an explosive eruption to be modelled, tracing the time-dependent development of the physical parameters of a simulated flow at a large three-dimensional mesh of points, based on assumed conditions of temperature, mass-flow rate and particle size distribution at the vent. The output includes mapping of temperature, mixture density and mixture velocity over the whole adjacent terrain. But to date this information has not been used to assess the impacts of such flows on buildings and their occupants. In the project reported in this paper, estimates of the near-ground flow parameters were used to assess the impact of a particular simulated pyroclastic flow (modelled roughly on the 1631 eruption) on the buildings and population in four of the Vesuvian villages considered most at risk. The study had five components. First, a survey of buildings and the urban environment was conducted to identify the incidence of characteristics and elements likely to affect human vulnerability, and to classify the building stock. The survey emphasised particularly the number, location and type of openings characteristic of the major classes of the local building stock. In the second part of the study, this survey formed the basis for estimates of the probable impact of the pyroclastic flow on the envelope and internal air conditions of typical buildings. In the third part, a number of distinct ways in which human casualties would occur were identified, and estimates were made of the relationship between casualty rates and environmental conditions for each casualty type. In the fourth part of the study, the assumed casualty rates were used to estimate the proportions of occupants who would be killed or seriously injured for the assumed pyroclastic flow scenario in the Vesuvian villages studied, and their distribution by distance from the vent. It was estimated that in a daytime eruption, 25 min after the start of the eruption, there would be 480 deaths and a further 190 serious injuries, for every 1000 remaining in the area. In a night-time scenario, there would be 360 deaths with a further 230 serious injuries per 1000 after the same time interval. Finally, a set of risk factors for casualties was identified, and factors were discussed and ranked for their mitigation impact in the eruption scenario. The most effective mitigation action would of course be total evacuation before the start of the eruption. But if this were not achieved, barred window openings or sealed openings to slow the ingress of hot gases, together with a reduction of the fire load, could be effective means of reducing casualty levels.

Medical effects of volcanic eruptions

Excluding famine and tsunamis, most deaths in volcanic eruptions have been from pyroclastic flows and surges (nuées ardentes) and wet debris flows (lahars). Information on the causes of death and injury in eruptions is sparse but the available literature is summarised for the benefit of volcanologists and emergency planners. In nuées, thermal injury may be at least as important as asphyxia in causing immediate deaths. The high temperature of the gases and entrained particles readily causes severe burns to the skin and the air passages and the presence of both types of injury in an individual may combine to increase the delayed mortality risk from respiratory complications or from infection of burns. Trauma from missiles or body displacement is also common, but the role of asphyxiant or irritant gases, and steam, remains unclear. The ratio of dead: injured is much higher than in other natural disasters. At the periphery of a nuée being protected inside buildings which remain intact appears to greatly increase the chances of survival. In lahars, infected wounds and crush injury are the main delayed causes of death, and the scope for preventive measures, other than evacuation, is small. The evidence from Mount St. Helens, 1980, and other major eruptions indicates that, although mortality is high within the main zone of devastation and in the open, emergency planning should concentrate on the periphery of a nuée where preventive measures are feasible and could save many lives in densely populated areas.

Risk assessment of residential buildings for an eruption of Furnas Volcano, São Miguel, the Azores

This paper presents the results of a study of the risks to human settlements of a future eruption of the Furnas Volcano in the Azores. It makes use of previous geological studies to estimate the likely impact of the volcanic hazards on the surrounding settlements, given an eruption comparable with the last major eruption in the island in 1630; it presents the results of a comprehensive building-by-building survey of the settlements at risk to determine the exposure of the residential building stock to these hazards; and it uses data from recent experience of volcanic eruptions elsewhere to estimate the vulnerability of the buildings to each hazard and the likely scale of human casualties and building damage. The paper concludes with some recommendations for preparedness and protective measures which could be taken before an eruption to reduce the risk of human casualties from roof and building collapses. Principal among these are recommendations for strengthening the lateral load resistance of buildings built with the traditional vernacular techniques to better resist groundshaking during eruptions and earthquakes; upgrading local building code requirements with view to increasing the live load resistance of roofs, to levels similar to those applied in areas of heavy snowfalls, to prevent roof collapse from tephra loading. Other preparedness measures are also discussed with respect to volcanic earthquakes, volcanic bomb impact, pyroclastic flows and tephra falls. Many aspects of this paper are relevant to other volcanic areas around the world.

Assessment of the exposure of islanders to ash from the Soufriere Hills volcano, Montserrat, British West Indies

Background and Aims: The Soufriere Hills volcano, Montserrat, has been erupting since July 1995 and volcanic ash has fallen on the island throughout most of the eruption. The ash contains substantial quantities of respirable particles and unusually large amounts (15–20%) of the crystalline silica mineral, cristobalite. The purpose of the surveys described here, undertaken between December 1996 and April 2000, was to determine levels of personal exposure of islanders to volcanic ash and cristobalite in order to inform advice on the associated risks to health and the measures required to reduce exposure. Methods: Surveys of personal exposure to respirable dust and cristobalite were undertaken using cyclone samplers. In addition, direct reading instruments (DUSTTRAK) were used to monitor ambient air concentrations of PM10 at fixed sites and also to provide information about exposures to airborne particles associated with selected activities. Results: Environmental concentrations of airborne ash have been greatest in the areas where the most ash has been deposited and during dry weather. Individual exposure to airborne ash was related to occupation, with the highest exposures among gardeners, cleaners, roadworkers, and police at roadside checkpoints. During 1997 many of these individuals were exposed to concentrations of cristobalite that exceeded the ACGIH recommended occupational exposure limit. Since the population became confined to the north of the island in October 1997, even those in relatively dusty occupations have received exposures to cristobalite well below this limit. Conclusions: Most of the 4500 people who have remained on island since the eruption began have not been exposed to sufficiently high concentrations of airborne dust for long enough to be at risk of developing silicosis. However, more than a dozen individuals continued to experience frequent high occupational exposures to volcanic ash, some of whom may have had sufficient exposure to crystalline silica to be at risk of developing mild silicosis. If volcanic activity were to deposit further ash over the occupied areas of the island during the coming years, the risks of silicosis will become more substantial.

Quantifying volcanic hazard at Campi Flegrei caldera (Italy) with uncertainty assessment: 1. Vent opening maps

Campi Flegrei is an active volcanic area situated in the Campanian Plain (Italy) and dominated by a resurgent caldera. The great majority of past eruptions have been explosive, variable in magnitude, intensity, and in their vent locations. In this hazard assessment study we present a probabilistic analysis using a variety of volcanological data sets to map the background spatial probability of vent opening conditional on the occurrence of an event in the foreseeable future. The analysis focuses on the reconstruction of the location of past eruptive vents in the last 15 ka, including the distribution of faults and surface fractures as being representative of areas of crustal weakness. One of our key objectives was to incorporate some of the main sources of epistemic uncertainty about the volcanic system through a structured expert elicitation, thereby quantifying uncertainties for certain important model parameters and allowing outcomes from different expert weighting models to be evaluated. Results indicate that past vent locations are the most informative factors governing the probabilities of vent opening, followed by the locations of faults and then fractures. Our vent opening probability maps highlight the presence of a sizeable region in the central eastern part of the caldera where the likelihood of new vent opening per kilometer squared is about 6 times higher than the baseline value for the whole caldera. While these probability values have substantial uncertainties associated with them, our findings provide a rational basis for hazard mapping of the next eruption at Campi Flegrei caldera.

Physicochemical and toxicological profiling of ash from the 2010 and 2011 eruptions of Eyjafjallajökull and Grímsvötn volcanoes, Iceland using a rapid respiratory hazard assessment protocol.

The six week eruption of Eyjafjallajökull volcano in 2010 produced heavy ash fall in a sparsely populated area of southern and south eastern Iceland and disrupted European commercial flights for at least 6 days. We adopted a protocol for the rapid analysis of volcanic ash particles, for the purpose of informing respiratory health risk assessments. Ash collected from deposits underwent a multi-laboratory physicochemical and toxicological investigation of their mineralogical parameters associated with bio-reactivity, and selected in vitro toxicology assays related to pulmonary inflammatory responses. Ash from the eruption of Grímsvötn, Iceland, in 2011 was also studied. The results were benchmarked against ash from Soufrière Hills volcano, Montserrat, which has been extensively studied since the onset of eruptive activity in 1995. For Eyjafjallajökull, the grain size distributions were variable: 2-13 vol% of the bulk samples were <4 µm, with the most explosive phases of the eruption generating abundant respirable particulate matter. In contrast, the Grímsvötn ash was almost uniformly coarse (<3.5 vol%<4 µm material). Surface area ranged from 0.3 to 7.7 m2 g(-1) for Eyjafjallajökull but was very low for Grímsvötn (<0.6 m2 g(-1)). There were few fibre-like particles (which were unrelated to asbestos) and the crystalline silica content was negligible in both eruptions, whereas Soufrière Hills ash was cristobalite-rich with a known potential to cause silicosis. All samples displayed a low ability to deplete lung antioxidant defences, showed little haemolysis and low acute cytotoxicity in human alveolar type-1 like epithelial cells (TT1). However, cell-free tests showed substantial hydroxyl radical generation in the presence of hydrogen peroxide for Grímsvötn samples, as expected for basaltic, Fe-rich ash. Cellular mediators MCP-1, IL-6, and IL-8 showed chronic pro-inflammatory responses in Eyjafjallajökull, Grímsvötn and Soufrière Hills samples, despite substantial differences in the sample mineralogy and eruptive styles. The value of the pro-inflammatory profiles in differentiating the potential respiratory health hazard of volcanic ashes remains uncertain in a protocol designed to inform public health risk assessment, and further research on their role in volcanic crises is warranted.

Acute health impact of the gas release at Lake Nyos, Cameroon, 1986

Abstract Available medical evidence on the acute health impact of the gas release at Lake Nyos is summarised, including the results of a survey of medical records of 845 survivors treated at Wum and Nkambe hospitals. The main clinical features were compatible with exposure to an asphyxiant gas such as CO 2 but confirmation of the identity of the gas or gases involved was not possible. Exposure to CO 2 over such a large inhabited area and reversible coma lasting for hours after CO 2 gassing do not appear to have been reported before. In some victims, blistering or ulceration of the skin was present which could not be readily explained by local injury from pressure, or burns from acid, or falling near fires. Further epidemiological studies on survivors are unlikely to be feasible, but the possibility of long-term anoxic brain damage among adults and children who had been rendered comatose by the gas should be considered, though overt evidence of major neurological or respiratory disability was not apparent in survivors in the weeks following the disaster. The inadequacy of the toxicological and forensic evidence obtained points to the need for the rapid mobilisation of medical scientists in future disasters of this kind.