Construction hazardous substances: Key points

Construction workers are exposed to many different types of hazardous substances such as dust, lead or cement. You need to be aware of the substances you are working with, how these could get into your body and what the potential health effects are. Below are some key points.


Hazardous substances come in a number of different forms:

  • Solids - including particles of solid material that get into the air such as dust, fibres, smoke and fume.
  • Liquids - including fine sprays, mists and aerosols made up of small droplets of liquid – eg sprayed paint.
  • Vapours - gaseous forms of a liquid or solid, eg solvent vapour.
  • Gases - some processes can generate gases like carbon monoxide or engine exhaust gases.
  • Micro-organisms - microscopic organisms, like bacteria, viruses and fungi can be found almost everywhere.

Under certain conditions, a substance can exist in more than one form at the same time (eg paint spraying can produce fine mists of liquid droplets and also solvent vapour). Knowing the correct form(s) a hazardous substance takes is important for getting the right controls.

Exposure route

Hazardous substances can get into the body in a number of ways. There are three main routes:

  • Lungs and airways – hazardous substances can be inhaled in the air you are breathing. The lungs and airways are vulnerable to many of these substances like dust or isocyanates. Your lungs are also closely linked to the circulatory system so the oxygen we breathe in the air can be transferred to the blood and on to all the tissues and organs in the body. This means that harmful substances, like solvent vapours, could also get into your blood  and be distributed around your body.
  • Skin – some substances, such as cement, can directly affect your skin through contact leading to problems like dermatitis or burns. Other substances, eg solvents, can be absorbed through your skin into the blood. Harmful micro-organisms can also get into your body through cuts and wounds.
  • Mouth – everyone eats and drinks. Some people also smoke. You can therefore transfer hazardous substances into your body eg when eating or smoking with hands contaminated with lead dust.


Different substances can harm your health in different ways. Some of these occur more immediately, like dizziness, headaches and nausea from solvents or burns from cement. Others, such as lung diseases, can take much longer and sometimes many years to develop.

Construction is a high-risk industry for health issues. Hazardous substances cause many of these issues, particularly in relation to occupational cancers where the industry has the largest burden amongst the industrial sectors.

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Updated 2022-11-01