Monitoring for Health Hazards at Work

John Cherrie, Sean Semple, Marie Coggins

• Publisher: Wiley-Blackwell
• Year: 2021
• ISBN:
  9781119614999
• Edition: 5
• Topic: Technology & Engineering
• Subtopic: Industrial Health & Safety
• Index: Technology & Engineering

MONITORING FOR HEALTH HAZARDS AT WORK

Monitoring for Health Hazards at Work remains the seminal textbook on measuring and ­controlling the risk of workplace exposure to physical, chemical, and biological hazards. Designed for students studying occupational hygiene and exposure science, this comprehensive and accessible volume provides step-by-step guidance on identifying hazards and quantifying their risks in various workplace environments. Complete with checklists and practical examples, the authors present clear explanations of all types of hazards that can arise in the workplace, including dust, particles, fibrous aerosols, gases, vapours, and bioaerosols.

The fifth edition features revised material throughout, and remains an essential resource for students and professionals in occupational hygiene, reflecting global standards and recent developments in monitoring equipment, modelling methods, exposure assessment, and legislation on workplace safety.

• Several new or substantially revised chapters cover topics such as human biomonitoring, exposure modelling, hazardous substances, physical agents, evaluating ventilation, PPE, and other control measures
• Updated sections discuss the equipment currently available, the importance of risk communication, assessing dermal and inadvertent ingestion exposures, and more
• Examines common workplace comfort issues such as noise, vibration, heat and cold, and lighting
• Offers practical advice on conducting and presenting risk assessments and reports
• Discusses the future of the development and application of hazard measurement equipment and methods

Monitoring for Health Hazards at Work, is required reading for students and professionals in occupational hygiene, environmental health and safety, occupational health and safety, and exposure science.

PART 1
Introduction

CHAPTER 1
Occupational Hygiene and Risk Assessment

1.1 INTRODUCTION

When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind…

Source: Popular lectures and addresses by Kelvin, William Thomson, In Three Volumes Vol. I. Constitution of Matter, London Macmillan 1889.

Scientists have always known that measurement is fundamental to making accurate statements about the world around us. The pioneers of occupational health were also enthusiastic about measuring exposure, even when this involved considerable effort to get reliable data. In recent years, it has become less fashionable to rely on measurement data and we have seen the development of sophisticated computer‐based systems to estimate exposures, or health and safety professionals rely on their judgement to come to a conclusion about the risks in a particular situation. We support these approaches, but we also recognise that which was clear to Lord Kelvin more than 100 years ago: measurements can provide a precise, reliable and objective description of a situation that is generally superior to the alternatives.

The science of human exposure encompasses assessment and control of exposure to hazardous agents that arise from work, in the home or elsewhere in the environment. It does not really matter whether you want to measure the exposure to diesel engine exhaust particulate of someone working as a truck driver or the exposure of someone else in the street where the truck is unloading: the underlying science is the same. Where differences do arise, they are in relation to who has responsibility to manage the exposures and what legislative regime applies to control exposure. Occupational health professionals are concerned with establishing and maintaining a safe and healthy working environment. Occupational hygienists are the occupational health professionals who are focused on the prevention of ill health by intervening in the workplace to eliminate or reduce exposures to hazardous agents. There are other occupational health and safety specialists who may deal with different aspects of health and work, for example occupational physicians and nurses, safety advisors and ergonomists. However, no matter what the specific expertise of the individuals they should be aware of the principles of occupational hygiene to help them in their job.

Hazardous agents may be chemicals, loud noise, unseen radiations or many other things. The discipline of occupational hygiene groups hazardous agents into three categories: physical, chemical or biological agents. Psychological stressors are generally seen as being outside the remit of occupational hygiene, and we do not consider them in this book. Similarly, ergonomic hazards, such as the risks form lifting loads or repetitive movements, are outside the scope of this book. Physical agents include noise, vibration, electromagnetic radiation, ionising and non‐ionising radiation, excessively hot or cold environments and abnormal atmospheric pressures. Chemical agents include harmful dusts, liquids, gases and vapours. Biological agents include bacteria, viruses and other materials of biological origin that are harmful to health. For convenience, chemical and biological agents are often grouped together as substances hazardous to health.

The basis for occupational hygiene is the link between exposure to a hazard and the risk of illness arising from that exposure, where the ‘hazard’ is the potential for harm and the ‘risk’ is the chance that that harm may arise in a particular situation. In general, it is assumed that the higher the exposure someone experiences, the greater the risk to their health. Figure 1.1 shows an idealised exposure–response relationship for a hazardous agent, which epitomises the causal link between these two measures. The point at which the line cuts the horizontal axis is the threshold for this particular agent and exposure less than this value will not cause any adverse effects. It is clear that limiting the exposure below the threshold will prevent anyone becoming ill and, in these circumstances, an occupational exposure limit (OEL) should ideally be defined at this point; i.e., it is a health‐based OEL. Note that in this book we use the term OEL to refer in a general way to limit values for workplace exposures.

Figure 1.1 An idealised exposure–response relationship.

One of the main reasons that this book does not attempt to encompass psychological hazards or other hazardous exposures encountered at work such as lifting heavy loads is because they often do not have a simple exposure–response relationship, and so greater stress at work does not always imply that there will be more ill‐health occurring.

In practice, the setting of OELs is more complex than the identification of a simple unambiguous threshold on an exposure–response curve, but the general principle of restricting exposure below some value, to ensure risk is minimised, is still valid. In some cases, we cannot identify whether the exposure–response relationship contains a threshold below which the hazardous agent has no effect; i.e. the exposure–response line does not reach zero risk. The main types of hazardous agents that may be in this category are carcinogens that act on the structure of DNA – so‐called genotoxic carcinogens. Also, people express a range of different susceptibilities to hazardous agents and although in theory, there may be a threshold for a given agent it may be that some individuals will still be affected at lower exposures. For example, someone with asthma may react to quite low concentrations of an irritant gas when others do not experience any ill effects. Finally, there may be factors that make it impracticable to set a limit at a threshold, for example it may not be technically or economically feasible to restrict exposure to the level of a low threshold and society deems that the benefits from production or use of this material outweigh the health risks from the exposure.

There are many systems that are in place to derive OELs: some are based on national legislation and are used to enforce the law in the workplace; some are national or international advisory limits without any direct link to legislation and some are international limits with the intention of harmonising practice. In Britain, there is a system for workplace exposure limits (WELs) for substances hazardous to health, which are linked to the legal provisions of the control of substances hazardous to health (COSHH) regulations. Each country in Europe has its own limits, but the European Union has set uniform minimum standards for OELs for some hazardous substances, in the past through the efforts of the Scientific Committee for Occupational Exposure Limits (SCOEL) and more recently through the European Chemicals Agency (ECHA) Committee for Risk Assessment (RAC). The European Commission then uses the scientific advice to make proposals for indicative occupational exposure limits based only on the scientific advice given or binding limits where socioeconomic or technical feasibility factors are taken into account in the decision. In the USA, the non‐governmental organisation, the American Conference for Governmental Industrial Hygienists (ACGIH) has had a lo...