COSHH for Construction: What It Means and How to Comply on Site

Health risks from long-term exposure to hazardous substances are the leading cause of death in construction. Past exposures in the construction sector cause over 5,000 occupational cancer cases and approximately 3,700 deaths each year. Despite this, many sites still fail to adequately assess and control these dangers. Understanding COSHH and implementing proper safeguards can prevent serious ill health and protect employees from substances that cause cancer, lung disease, and dermatitis.

What Is COSHH in Construction?

COSHH stands for Control of Substances Hazardous to Health. It is a set of regulations designed to protect workers from exposure to harmful substances in the workplace.

In the construction industry, COSHH applies to substances that are used, stored, or created during construction activities, including building materials brought onto site and substances generated by cutting concrete or bricks, or mixing cement.

COSHH covers airborne particulates, fumes, vapours, mists, liquids, and biological agents. The construction industry accounts for over 40% of occupational cancer deaths, making it one of the highest-risk sectors for COSHH exposure.

Why COSHH Is Especially Important on Construction Sites

The biggest killer in construction is not falls or accidents, but long-term occupational disease. Workers face cumulative exposure across multiple sites throughout their careers. Temporary sites with changing health hazards make management more complex. What starts as groundwork becomes structural work, then fit-out, with different dangerous substances introduced at each stage.

High workforce turnover and extensive subcontracting mean personnel may not receive consistent training or surveillance across different workplaces. These factors combine to create an environment where hazardous material exposure can easily go uncontrolled, causing serious health consequences decades later.

Common COSHH Hazards in Construction

Building sites commonly use hazardous substances such as cement, paints, plaster, lead, and fuels. The following covers the frequent COSHH exposures on site and the health risks they present.

Construction Dusts

Dust is one of the most significant COSHH risks on construction sites. Construction workers often overlook the risks associated with hazardous substances due to their frequent use, but dust inhalation causes permanent, life-changing damage.

• Silica dust is created when cutting bricks, grinding, or drilling materials containing silica, including concrete, blocks, and mortar. It is a significant health risk in construction, as it can lead to serious lung diseases.

• Wood dust, including MDF, is produced during cutting, sanding, and machining timber. Exposure can bring health issues, including asthma and cancer.

• Cement dust becomes airborne during pouring, mixing, and demolition of concrete structures.

Health effects from construction particulates include:

• Silicosis (permanent scarring of lung tissue)
• COPD (chronic obstructive pulmonary disease)
• Asthma
• Lung cancer
• Dermatitis (from cement particles on skin)

Cement and Wet Concrete

Cement is both alkaline and corrosive. Direct contact causes skin and eye damage within minutes, and prolonged exposure leads to dermatitis. Cement particles can penetrate clothing and footwear, causing chemical burns. Mixing cement or working with wet concrete without proper protection creates immediate risk of harm.

Solvents, Paints, Adhesives, and Sealants

These substances release vapours during application and curing. Skin contact with certain chemicals can lead to sensitisation or dermatitis. Isocyanates found in some paints and sealants, and epoxies used in flooring and coatings, are common during finishing and fit-out work. These can cause severe respiratory issues and skin reactions, with effects that may be permanent.

Welding and Cutting Fumes

Welding produces toxic and potentially carcinogenic fumes. The specific risks depend on the metals being welded and any coatings present. This applies to both indoor and outdoor work, as fumes can accumulate even in seemingly well-ventilated areas.

Fuels, Oils, and Exhaust Fumes

Diesel exhaust from plant and machinery contains harmful substances linked to lung cancer. Emissions from construction equipment in confined or semi-enclosed spaces can quickly reach dangerous concentrations. Fuels, oils, and other chemicals used for plant maintenance also present exposure risks through skin contact and inhalation.

Who Is Responsible for COSHH on a Construction Site?

COSHH regulations clearly define shared responsibilities on construction environments.

The principal contractor has overall responsibility for coordinating compliance across the site, ensuring control measures are in place, and facilitating information exchange between employers.

• Employers and subcontractors must identify hazardous substances their employees will use or be exposed to, conduct risk assessments, implement countermeasures, provide training, and arrange health monitoring where required. They must provide employees with suitable and sufficient information, instruction, training, and supervision regarding hazardous substances.

• Site managers and supervisors must ensure harm mitigators are used correctly, maintained properly, and that work methods follow the risk assessment.

• Workers have a duty to cooperate with their employers to enable compliance with regulations. This includes using PPE and following safe work procedures.

The idea that "it's the subcontractor's issue" fails legally. All duty holders remain responsible for protecting anyone affected by their work.

COSHH Risk Assessments in Construction

Employers must identify the hazardous substances in the workplace and assess the risks they pose to people's health. A risk assessment should be carried out by a competent person who understands regulations and the relevant Approved Codes of Practice.

In construction, COSHH assessments must be task-specific and reflect actual site conditions, including ventilation, confined spaces, and the number of personnel exposed. They should link directly with method statements so staff understand what protections apply. The assessment involves evaluating who is at risk, how often they are exposed, and how substances may enter the body through inhalation, skin contact, or ingestion.

Controlling COSHH Risks on Construction Sites

COSHH regulations require businesses to prevent exposure to substances hazardous to health or, if prevention is not reasonably practicable, to adequately manage hazardous substances.

Safeguards must follow a hierarchy:

1. Elimination: Change the design or method to avoid creating or using the hazardous substance entirely.

2. Substitution: Replace hazardous materials with safer alternatives, such as pre-mixed products, to reduce risk.

3. Engineering controls: Use on-tool extraction when cutting or grinding, water suppression, and local exhaust ventilation systems.

4. Administrative controls: Plan work to minimise exposure time, sequence tasks to reduce the number of employees affected, and implement permit systems for high-risk activities.

5. Personal protective equipment: Provide respiratory protective equipment, protective clothing, gloves, and barrier creams only when other safeguards are inadequate.

PPE should be provided only as a last resort and never as a replacement for other protections. It can reduce harm for only one user at a time and does not eliminate the danger.

Dust Control on Construction Sites (COSHH Expectations)

Airborne particulate management is a primary focus during inspections. The Health and Safety Executive typically expects to see the following in place:

• On-tool extraction: Power tools fitted with extraction attachments connected to vacuum systems rated for the particulate type.

• Water suppression: Wet cutting methods for concrete, masonry, and stone to prevent material becoming airborne.

• Enclosures and segregation: Physical barriers or designated areas to contain work and protect nearby staff.

• Good housekeeping: Regular cleaning using vacuum systems rather than brushing or compressed air. Proper ventilation and substituting hazardous substances with safer alternatives can also significantly reduce the danger.

Safeguards must be kept in efficient working order and properly maintained. Regular checks should ensure procedures are being followed and risks remain well managed.

COSHH Training and Information on Site

Employers must educate workers on the substance, the risk that it poses, and how the risk can be reduced.

Site induction should cover general COSHH awareness, how to identify hazardous substances, and where to gain access to safety reports and safety data sheets. Task-specific COSHH training must be provided before workers start activities involving hazardous substances. This should explain the specific risks, demonstrate correct use of control measures, and cover emergency procedures.

Toolbox talks provide opportunities to reinforce workplace messages and address health and safety as site conditions change. Language and literacy considerations are essential on diverse construction sites. Visual aids, demonstrations, and translated materials may be necessary to ensure understanding.

Employers must ensure that employees are trained to use control measures, including PPE, correctly.

Health Surveillance in Construction

Health surveillance is required when staff are exposed to substances that can cause identifiable disease, and there is reasonable likelihood of this occurring under actual working conditions.

This typically includes:

• Regular health checks for those exposed to silica or wood particulates (including lung function tests)
• Skin surveillance for those regularly handling cement or wet concrete
• Respiratory well-being checks for welders
• Monitoring for those using isocyanates, epoxy resins, and other sensitisers

Employers are responsible for arranging and funding surveillance. Records must be kept and personnel informed of results. Monitoring air quality or substance concentrations helps ensure they remain below Workplace Exposure Limits.

COSHH and Subcontractors

COSHH duties apply to all employers on site, regardless of contract structure. Shared duties mean the principal contractor and subcontractors must work together.

Information exchange is critical. Subcontractors need to know what hazardous substances are already present on site. The principal contractor needs to understand what substances subcontractors will introduce and what safeguards they will use.

Coordination of controls prevents gaps. If one trade creates dust, other trades working nearby need protection. The argument that "it's the subcontractor's issue" fails legally because all duty holders remain responsible for protecting anyone affected by their work.

Common COSHH Failures on Construction Sites

Many construction sites still fail to adequately assess the risks from exposure to hazardous substances. Understanding where sites commonly go wrong helps prevent these failures.

• Generic assessments: Using template assessments that do not reflect actual site conditions or specific tasks

• PPE-only control: Relying solely on personal protective equipment without implementing other mitigators

• Poor dust control: Working without on-tool extraction or water suppression when cutting or grinding

• Unlabelled decanted substances: Transferring chemicals into unmarked containers, making it impossible to identify hazards

• No health surveillance: Failing to arrange required health checks for workers with ongoing exposure

• No review as site changes: Not updating assessments when work methods, materials, or site conditions change

Failure to identify hazardous substances on site can lead to underestimating potential risks and serious health consequences for workers.