12. Chemical and biological health hazards

There are many substances used at work that are potentially hazardous to health. They are typically described as either chemical hazards (which cause harm to body) or biological hazards (which cause illness).

Reference – ‘COSHH: A brief guide to the Regulations’ available free at http://www.hse.gov.uk/pubns/indg136.pdf

Reference – ‘EH40/2005 Workplace exposure limits – Containing the list of workplace exposure limits for use with the Control of Substances Hazardous to Health Regulations 2002 (as amended)’ available free at https://www.hse.gov.uk/pubns/priced/eh40.pdf

Safety issues related to hazardous substances

Sources of hazardous substances

People can be exposed to hazardous substances in a number of ways, including:

  • Substances being used directly in work activities (e.g. adhesives, paints, cleaning agents);
  • Substances generated during work activities (e.g. fumes from soldering and welding);
  • Naturally occurring substances (e.g. grain dust);
  • Biological agents such as bacteria and other micro-organisms.

Potential consequences of exposure to hazardous substances

The type of harm that may occur if someone is exposed to a hazardous substance includes:

  • Skin irritation or dermatitis as a result of skin contact;
  • Asthma being triggered by a substance at work;
  • Losing consciousness as a result of being overcome by fumes;
  • Cancer, which may appear long after the exposure to the chemical that caused it;
  • Infection from bacteria and other micro-organisms (biological agents).

Exposure can cause immediate ‘acute’ effects or create longer term ‘chronic’ health problems (e.g. people become sensitised or develop cancer and other illnesses).

Also, people can have allergic reactions to substances. This is where the immune system over-reacts to a substance that is safe for most people (e.g. food stuff).

Hazardous chemicals

Chemicals can cause harm if they are:

  • Breathed in (inhaled) – can damage lungs or enter the blood stream via the lungs;
  • Eaten or drunk (ingested) – if present in food or drink, or is on someone’s hands when they are eating or put their hand in their mouth;
  • In contact with the skin or eyes;
  • Absorbed through the skin – can affect internal organs;
  • Injected into the body – includes accidental puncture wounds with a contaminated item.

The effects can be

  • Local – only affect the part of the body exposed (skin, eyes, mouth, stomach, lungs);
  • Systemic – spread through the body (blood, bones, liver, nervous system);
  • Cumulative – may not have an effect on first exposure, but repeated exposure causes problems.

Chemical hazard classifications

Chemicals are generally classified into one or more of the following:

  • Very toxic;
  • Toxic;
  • Harmful;
  • Corrosive;
  • Irritant;
  • Sensitising;
  • Carcinogenic;
  • Mutagenic;
  • Toxic for reproduction.

Material Safety Data Sheets (MSDS) should be available for all hazardous chemicals being used or produced. As well as the classification, the sheets should include chemical and physical properties, precautions for use, first aid and fire fighting.

European Regulation (EC) No 1272/2008 on Classification, Labelling and Packaging (CLP) of substances and mixtures came into force on 20 January 2009 in all EU Member States, including the UK.

The CLP Regulation adopts the United Nations’ Globally Harmonised System on the classification and labelling of chemicals (GHS) across all European Union countries, including the UK.

Reference – “The CLP Regulation” available free at http://www.hse.gov.uk/chemical-classification/legal/clp-regulation.htm

Chemical exposure limits

In the UK Workplace Exposure Limits (WEL) are set for a number of substances hazardous to health. They are the maximum concentrations of an airborne substance, averaged over a reference period (15 minutes for short term and 8 hours for long term exposure), to which employees may be exposed by inhalation.

It is worth noting that even supposedly inert dusts (i.e. non-toxic) can cause health affects if inhaled, and so have a WEL of 10 mg/m3

Biological hazards

Substances considered to be biological hazards are any micro-organism, cell culture, or human endoparasite, whether or not genetically modified, which may cause infection, allergy, toxicity or otherwise create a hazard to human health.

They are classified into hazard groups as follows:

1. Unlikely to cause human disease;

2. Can cause human disease and may be a hazard to employees. Unlikely to spread to the community and there is an effective prophylaxis or treatment available;

3. Can cause severe human disease and may be a serious hazard to employees. May spread to the community, but there is an effective prophylaxis or treatment available;

4. Causes severe human disease and is a serious hazard to employees. Is likely to spread to the community and there is no effective prophylaxis or treatment available.

Reference – ‘ The HSE has a page dedicated to biosafety at https://www.hse.gov.uk/biosafety/information.htm

Managing risks of hazardous substances

The following stages are required to manage the risks of hazardous substances:

1. Assess the risks to health from hazardous substances;

2. Decide what precautions are needed whenever employees may be exposed;

3. Prevent exposure. Where this is not reasonably practicable, then control it;

4. Ensure that control measures are used and maintained;

5. Monitor the exposure of employees to hazardous substances (if shown as necessary by the risk assessment or is required by regulations);

6. Carry out appropriate health surveillance (if shown as necessary by the risk assessment or is required by regulations);

7. Prepare plans and procedures to deal with accidents, incidents and emergencies;

8. Ensure employees receive necessary information, instruction and training.

Specific substances

Requirements for specific hazardous substances are shown in Appendix B.

Control of Substances Hazardous to Health 2002 (COSHH) regulations

The COSHH regulations apply to chemical and biological hazards. They require employers to control exposure to hazardous substances to prevent ill health. It is necessary to protect both employees and others who may be exposed.

Reference – Approved Code of Practice L5 ‘The Control of Substances Hazardous to Health Regulations 2002 (as amended)’ available free at http://www.hse.gov.uk/pubns/priced/l5.pdf

Registration, Evaluation and Authorisation of Chemicals (REACH)

Introduced in June 2008, REACH is the system for controlling chemicals based on European legislation. Its main aim is to ensure adequate information about the potential health effects of chemical use is known.

REACH places most duties on the manufacturers and importers, who are required to gather information on the properties of the substances they supply, register this on a central database and pass it on to their customers. Users of chemicals do have some duties, particularly where they use chemicals that are different to those considered by the manufacturer or importer.

A wealth of information is available from http://www.hse.gov.uk/reach

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