Last reviewed 15 April 2021

Caroline Raine discusses how to work safely with hazardous products and substances that are commonly found on construction sites. She discusses the steps to be taken and give tips on best practice.

Work on construction sites can involve the risks of exposure to numerous hazardous substances, most of which are substances hazardous to health or materials that are capable of forming flammable or explosive atmospheres. The Control of Substances Hazardous to Health Regulations 2002 (COSHH) apply to substances that are hazards to health and the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR) apply to dangerous substances, materials that are capable of forming flammable or explosive atmospheres.

This article will concentrate on substances hazardous to health rather than those capable of forming flammable or explosive atmospheres.

Risk assessments

COSHH requires employers to carry out a full risk assessment before any work is undertaken with any substance hazardous to health. The assessment should identify the steps required to prevent employees being exposed to substances hazardous to health or, if prevention is not reasonably practicable, to adequately control the exposure.

The risk assessment requires:

  • information to be gathered about the hazardous substances at the workplace and ways they are used

  • evaluation of the likelihood of exposure and risks to health

  • determination of the measures required to prevent employees being exposed to the substances or to adequately control the exposure.

The assessment must be recorded and reviewed.

Typically the Five Step approach to COSHH is undertaken.

  • Step 1 — Gather the information.

  • Step 2 — Evaluate the risks.

  • Step 3 — Decide on the necessary measure to prevent or to adequately control exposure of employees to the substances.

  • Step 4 — Record the assessment.

  • Step 5 — Review the assessment.

Steps 1, 2, 4 and 5 are self-explanatory. Step 3 needs to consider the following.

  • Prevention or control of exposure to substances hazardous to health

  • Use of control measures

  • Maintenance, examination and testing of control measures

  • Monitoring exposure

  • Health surveillance

  • Sufficient information, instruction and training

  • Arrangements to deal with accidents, incidents and emergencies.

In order of priority, the measures include: avoiding use of the hazardous substance; altering process design; and working procedures and altering engineering controls. If control measures cannot be achieved by other means, the use of personal protective equipment (PPE) in addition to the other measures may be introduced. It is important to note that PPE must be used as a last resort; other control must be considered and implemented first.

Having discussed what should be done in the way of risk assessment to ensure the safety of all those involved in the use of the hazardous substances, let’s now consider some specific products and substances.

Cement and concrete

Cement is commonly found on construction sites and can cause skin and eye irritation. Cement is typically delivered pre-mixed in bags for instance use, which cuts down on the dust created while mixing on site. However, the dust from the pre-mixed product can still cause problems, for example in windy conditions, or when sweeping up cement dusts. Therefore, when carrying out a COSHH assessment all conditions and uses must be taken into account.

There are a number of processes and controls that can be introduced to protect the worker, for example using a vacuum cleaner instead of sweeping. Make sure that there is adequate ventilation and that bags are not shaken when emptying the product. Wet down all dusts to minimise dust creation. Ensure that a manual handling assessment is undertaken for those moving the bags. Consider health monitoring and train staff to recognise the symptoms of dermatitis. Provide gloves and cream to staff to ensure their hands are protected. As mentioned above, PPE should be the last resort and once all other controls have been considered and implemented, gloves and goggles are likely to be required.

It is worth noting that wet concrete introduces other hazards; for example, alkali burns may result from prolonged skin contact and wet concrete can easily become trapped inside PPE making contact with the skin. Introduce procedures to ensure that PPE is regularly inspected and kept clean.

Construction work often involves the removal of concrete, and during that process dusts can be created; these dusts can create similar respiratory problems. Controls including the use of vacuums and dust suppression techniques (eg use of water, damping down) can be used.

It is especially important to consider the fact that the concrete may contain silica. Silica causes a condition of the lungs called silicosis, which causes shortness of breath and lung infections such as tuberculosis (TB). This condition is irreversible and usually follows many years of exposure, although short term high exposure has also been found to be responsible.


Petrol is often stored and used on site in construction machinery. Petrol may be fatal if swallowed and cause drowsiness or dizziness if it enters the airways. It can also cause skin irritation and could, it is suspected, damage fertility, harm the unborn child, and cause genetic defects or cancer. Procedures need to be put in place to prevent vapour being inhaled, swallowed or coming into contact with the skin. These include: training in the correct procedures when handling petrol, use of the correct personal protective equipment and washing properly with plenty of soap and water after finishing work, or at any time when petrol or oil comes into contact with hands. Employees should be made aware of the hazards and not to attempt to siphon petrol using their mouths. When dispensing or decanting petrol adequate ventilation must be available.

The COSHH assessment should consider all uses and applications; in addition to handling, the storage and transport of the petrol must also be taken into account.

Petrol is an extremely flammable liquid and vapour and, as required by DSEAR, requires a risk assessment to prevent the risks to employees from fires or explosions. This should ensure there are safe handling procedures, it is not stored in close proximity to where hot works are being carried out, there are no sources of ignition near to storage areas and any smoking area is well away from the petrol storage area.

Dangerous Substances (Notification and Marking of Sites) Regulations 1990 (NAMOS)

It is a legal requirement under NAMOS to notify the Fire and Rescue service (FRS) and the enforcing authority for the Health and Safety at Work, etc Act 1974 (eg the Health and Safety Executive or local authority) about any site with a total quantity of 25 tonnes or more of dangerous substances.

Any notification should include the following.

  • Name and address of the person making the notification.

  • Full address of the site.

  • Simple details of the business at, or planned for, the site.

  • The planned or estimated date such quantities will be present.

  • Classification of dangerous substances which are or are liable to be present at the site:

    • non-flammable compressed gas

    • oxidising substance

    • toxic gas

    • organic peroxide

    • flammable gas

    • toxic substance

    • flammable liquid

    • corrosive substance

    • flammable solid

    • harmful substance

    • spontaneously combustible substance

    • other dangerous substance

    • substance that emits flammable gas when in contact with water.

If there is present at any one time a total quantity of 25 tonnes or more of dangerous substances at the site. safety signs must be displayed at such places as will give adequate warning that dangerous substances are present to firemen before entering the site in an emergency.

Further information

  • L5 —The Control of Substances Hazardous to Health Regulations 2002. Approved Code of Practice and Guidance, HSE