A Brief Account of Chemicals and Human Health

Our environment contains various toxic chemicals. Beginning indoors, where we live and spend most of our time, and in the materials we use and come into contact with, there are a number of chemicals, any of which can affect human health in different ways and to different extents. 

Humans, and most vertebrate animals, may be seriously affected by exposure to certain chemicals under certain conditions, directly or indirectly these may constitute serious health hazards (leading to diseases), as well as physical hazards, including risk of death. 

The US Federal Organization of Safety and Health Administration (OSHA) categorises these chemicals in general, as follows  

Any of these substances can be a solid, a liquid, a gas, a vapour (which is the gaseous phase of a liquid or solid material at ambient temperature and pressure), an aerosol (a dispersion of microscopic solid or liquid particles in a gaseous medium), a smoke (an aerosol usually of carbon particles with less than 0.1 [xm diameter), or a fog (a visible liquid aerosol). 

In this book, hazards from exposure to chemicals will be considered, with special attention given to plastics and rubbers, since we use them extensively in almost all aspects of our everyday life and it is very important to understand their part as chemical health hazards. 

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