COSHH · Mandatory · Pre-Construction

COSHH Assessment — Lead at Work (General)

A COSHH assessment for lead exposure beyond decorative paint, covering lead sheet roofing, flashings, soldering, bossing, lead pipework, lead-primed structural steel, and demolition. WEL 0.15 mg/m³ inhalable dust and fume. Hot lead work (soldering, bossing, burning) generates fume requiring supplied air RPE, not just FFP3. Blood lead monitoring required under CLAW 2002 where significant exposure occurs. Suspension levels: 60 µg/dL males, 30 µg/dL females.

Last reviewed: 2 April 2026 — This guide reflects UK law as of this date. Control of Lead at Work Regulations 2002 + COSHH 2002 remains current with no amendments enacted as of 2 April 2026. Next scheduled review: 2 April 2027.

Primary legislation	Control of Lead at Work Regulations 2002 (CLAW 2002), supported by COSHH 2002 and MHSWR 1999
Lead sources in construction	Lead sheet roofing (flashings, gutters, valleys, church roofs), lead pipework, lead solder, lead-primed structural steel, demolition of buildings containing lead components
Key distinction	DUST vs FUME — cold work (cutting, sanding) generates lead dust; hot work (soldering, bossing, burning) generates lead fume. Fume particles are smaller, penetrate deeper into the lungs, and are absorbed faster. Controls differ significantly
Workplace Exposure Limit	0.15 mg/m³ (8-hour TWA) for lead and inorganic lead compounds
Suspension levels	Males: 60 µg/dL blood lead. Females of reproductive capacity: 30 µg/dL. Young persons (under 18): 15 µg/dL

1. Not Just Lead Paint

When construction professionals think of lead exposure, they almost invariably think of lead paint. There is a dedicated COSHH assessment for that hazard — and rightly so, given the volume of pre-1980 buildings that still contain it. But lead in the construction industry extends far beyond decorative coatings. Lead sheet has been used for centuries in roofing: flashings, gutters, valleys, and entire roof coverings on churches and historic buildings. Lead pipework remains in older water supply systems. Lead solder was the standard joining method for copper plumbing until its prohibition for potable water systems. Lead-based primers were used extensively on structural steelwork. And demolition of any pre-1980 building may disturb multiple lead-containing materials simultaneously.

The Control of Lead at Work Regulations 2002 (CLAW 2002) apply to all work that is liable to expose employees to lead — not just work involving lead paint. A roofer laying, cutting, or dressing lead sheet is exposed to lead dust from the cutting and handling process. A plumber soldering lead pipework or working with lead solder on copper joints is exposed to lead fume from the molten solder. A steelwork contractor cutting, grinding, or welding lead-primed steel is exposed to lead dust and fume. Each of these exposures requires a specific COSHH assessment under CLAW 2002, tailored to the particular task, lead source, and form of exposure.

Lead is a cumulative poison. Unlike many hazardous substances where the body can metabolise and excrete the material, lead is stored in bone tissue and accumulates over a working lifetime. A roofer who has laid and dressed lead sheet for thirty years may have significantly elevated blood lead levels that persist long after retirement. The damage is progressive and largely irreversible — affecting the nervous system, kidneys, reproductive system, and cardiovascular system. This is why CLAW 2002 imposes strict duties on employers: the consequences of inadequate control may not become apparent for decades, but by then the harm is done.

Hot lead work generates fume — not dust. Controls are fundamentally different.

Hot lead work — soldering, bossing, lead welding, and burning — generates lead fume, not lead dust. This distinction is critical because fume particles are far smaller than dust particles, penetrate much deeper into the lungs, and are absorbed into the bloodstream significantly faster. An FFP3 dust mask, which is adequate for cold lead cutting, is not adequate for hot lead work. Supplied air or air-fed respiratory protective equipment is required for any process that melts or vaporises lead. Using a dust mask for lead fume work is a critical control failure that exposes the worker to rapid and significant lead absorption.

2. Content

A COSHH assessment for lead at work under CLAW 2002 must address the specific lead source, work process, and form of lead generated. The following table sets out the key fields and the level of detail required in each.

Field	Detail required
Task assessed	Specific task description: e.g. “Soldering lead sheet flashings on pitched roof,” “Cutting lead pipework during strip-out,” “Flame cutting lead-primed steelwork.” Must be task-specific, not generic.
Lead source	Identify the specific material: lead sheet (specify gauge and application), lead pipework, lead solder, lead-primed structural steel, or mixed sources in demolition. Reference any survey or testing results confirming lead content.
Work process	Describe the process in sufficient detail to determine the form of lead generated: cold cutting with snips or saw, mechanical grinding, soldering with blowtorch, bossing with heated tools, flame cutting with oxy-acetylene.
Lead form generated	DUST (cold cutting, sawing, sanding, grinding, handling weathered lead sheet) or FUME (soldering, bossing, lead welding, burning, flame cutting). This distinction determines the RPE and ventilation requirements. Some tasks generate both.
WEL	0.15 mg/m³ (8-hour TWA) for lead and inorganic lead compounds. This applies to both dust and fume.
Exposure assessment	Qualitative assessment of likely exposure level relative to the WEL, taking into account the task duration, frequency, quantity of lead disturbed, and whether the work is indoors or outdoors. Air monitoring data from comparable tasks where available.
Controls — Wet methods	Wet cutting, wet sanding, damping down of lead sheet before handling to suppress dust. Misting during grinding or mechanical cutting. Not applicable to hot work (fume control required instead).
Controls — LEV/ventilation	Local exhaust ventilation at the point of fume or dust generation. For indoor hot lead work, LEV is mandatory. For outdoor hot work, natural ventilation with positioning upwind may be acceptable but must be assessed.
Controls — RPE	DUST tasks: minimum FFP3 (APF 20) disposable mask or half-mask with P3 filters. FUME tasks: supplied air or air-fed RPE is required — FFP3 is not adequate for lead fume. All tight-fitting RPE must be face-fit tested.
Controls — Protective clothing	Disposable overalls or dedicated work clothing that is not taken home. Gloves. Boot covers where lead dust contamination of footwear is likely. Clothing must be removed before entering welfare facilities.
Controls — Hygiene	Dedicated washing facilities adjacent to the work area. Hands and face must be washed before eating, drinking, or smoking. No eating, drinking, or smoking in the work area. Separate storage for work and personal clothing.
Controls — Medical surveillance	Blood lead monitoring required where there is reasonable likelihood of significant exposure. Suspension levels: males 60 µg/dL; females of reproductive capacity 30 µg/dL; young persons (under 18) 15 µg/dL. Arranged through occupational health provider. Records kept for 40 years.
Waste disposal	Lead waste (offcuts, dust, contaminated PPE, wipes) is hazardous waste under the Hazardous Waste Regulations 2005. Segregate on site, store in sealed labelled containers, dispose via licensed hazardous waste carrier.
Assessor	Name, qualifications, and competence of the person carrying out the assessment. Must have sufficient knowledge of CLAW 2002 and the specific lead work being assessed.

Dust vs fume: the RPE decision that matters most

The single most important decision in this COSHH assessment is correctly identifying whether the task generates lead dust or lead fume. Cold work on lead (cutting with snips, sawing, sanding, grinding, handling weathered lead sheet) generates dust. Hot work on lead (soldering, bossing, lead welding, burning, flame cutting) generates fume. Dust requires FFP3 filtration as a minimum. Fume requires supplied air or air-fed RPE — particulate filters alone are not adequate because fume particles are too small and too readily absorbed. Getting this distinction wrong means the worker's RPE provides inadequate protection for the actual exposure.

3. Common Mistakes

Assuming the lead paint COSHH assessment (C9) covers all lead work

The lead paint COSHH assessment covers decorative lead paint only — the specific hazard of disturbing lead-based coatings on building surfaces. Lead sheet roofing, lead pipework, lead solder, and lead-primed structural steel are entirely different materials with different work processes, different forms of exposure, and different control requirements. A roofer dressing lead sheet flashings has no connection to a decorator sanding lead paint. Each lead source and work process requires its own COSHH assessment under CLAW 2002. Relying on the lead paint assessment to cover lead sheet, solder, or pipework work leaves those exposures unassessed and uncontrolled.

Using FFP3 dust masks for hot lead work

FFP3 disposable masks and half-masks with P3 particulate filters are designed to filter airborne dust particles. They are adequate for cold lead work where the exposure is to lead dust. However, hot lead work — soldering, bossing, lead welding, and burning — generates lead fume, not dust. Fume particles are significantly smaller than dust particles, and the mechanism of lung deposition and absorption is different. FFP3 masks do not provide adequate protection against lead fume. Supplied air or air-fed respiratory protective equipment is the required standard for any hot lead process. Using a dust mask for fume work is a critical control failure that directly exposes the worker to rapid lead absorption through the lungs.

4. Frequently Asked Questions

When does CLAW 2002 medical surveillance apply?▾

Medical surveillance under CLAW 2002 is required where there is a reasonable likelihood of significant exposure to lead. In practice, this captures lead roofers who regularly work with lead sheet (laying, cutting, dressing, and particularly soldering flashings and joints); plumbers who work with lead solder or lead pipework more than occasionally; and steelwork contractors who cut, grind, or weld lead-primed structural steel. Medical surveillance must be arranged through an occupational health provider and includes regular blood lead level monitoring. The frequency of monitoring depends on the level and regularity of exposure but is typically every three to six months for regular lead workers. Records of blood lead monitoring must be kept for 40 years — reflecting the long latency period of lead-related disease and the cumulative nature of lead stored in bone tissue.

Does this assessment replace the lead paint COSHH assessment?▾

No. This assessment covers lead sources other than decorative lead paint — specifically lead sheet, lead pipework, lead solder, and lead-primed steel. The lead paint COSHH assessment (C9) remains the correct document for work involving lead-based decorative coatings. Where a project involves both lead paint removal and lead sheet roofing work, both assessments are required because the work processes, forms of exposure, and control measures differ. A refurbishment project on a pre-1960 building with lead paint on interior surfaces and lead sheet on the roof needs two separate lead COSHH assessments.

What blood lead level triggers suspension from lead work?▾

CLAW 2002 sets different suspension levels depending on the worker category. For adult males, the suspension level is 60 µg/dL — at this blood lead concentration, the worker must be removed from lead work until their level falls below the threshold. For females of reproductive capacity, the suspension level is 30 µg/dL, reflecting the severe risk that lead exposure poses to fetal development. For young persons (under 18), the suspension level is 15 µg/dL. These are legal limits, not guidelines. An employer who allows a worker to continue lead work after their blood lead level has reached or exceeded the relevant suspension level is committing an offence under CLAW 2002.

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