4.7 Lead in Buildings: Control of Lead at Work Regulations 2002 & Blood-Lead Surveillance

Why Lead Has Its Own Regulations

Section 4.1 established that a small group of substances is deliberately carved out of the Control of Substances Hazardous to Health (COSHH) Regulations 2002 because each needs a bespoke regime: asbestos under CAR 2012, radioactive substances under the Ionising Radiations Regulations 2017, and lead under the Control of Lead at Work Regulations 2002 (CLAW). CITB lists lead as a separate learning outcome in Module 2 of the SMSTS syllabus, and it deserves the space. Lead is a cumulative systemic poison: it is absorbed by inhalation and ingestion, stored in bone, and released back into blood over years. Its effects — anaemia, kidney damage, nervous system damage, raised blood pressure and impaired fertility — build silently, so the worker who is being harmed feels fine.

The site management problem is that lead is almost never on the job description. It arrives inside other tasks: stripping a roof, burning off paint, cutting out old pipework, demolishing a Victorian terrace.

Where Lead Turns Up on UK Sites

A pattern is visible: heat and abrasion are the two mechanisms that turn stable lead into a respirable fume or dust. Lead fume is generated above roughly 500°C, which any oxy-fuel torch, hot air gun or welding process comfortably exceeds. Cold, undisturbed lead sheet on a roof is not an exposure risk; the same sheet being cut with a disc cutter is.

The CLAW 2002 Duty Structure

CLAW imposes a familiar hierarchy but with tighter, prescriptive additions:

1. Assess the risk before work starts — identify whether lead is present (a refurbishment and demolition survey, paint sampling, or building age and construction), what form it is in, and whether the planned method will disturb it.
2. Prevent exposure where reasonably practicable — substitute lead-free materials, remove components intact rather than cutting them in situ, use chemical strippers or infrared systems instead of burning off, or engage a specialist contractor.
3. Control exposure where prevention is not reasonably practicable — local exhaust ventilation, on-tool extraction, wet methods, enclosure, and only then respiratory protective equipment with face-fit testing.
4. Prohibit eating, drinking and smoking in any area where lead exposure could occur. This is not housekeeping advice; ingestion from contaminated hands is a major route of lead uptake, and it is the route most often underestimated on site.
5. Provide washing and changing facilities and separate storage for contaminated work clothing. Lead dust taken home on overalls has poisoned workers' children — a documented UK phenomenon known as take-home exposure.
6. Air monitoring where required to check the effectiveness of controls.
7. Medical surveillance by an HSE appointed doctor where exposure is significant.
8. Information, instruction and training for every exposed worker, and maintenance of records.

The Numbers You Must Know

Occupational exposure limit in air

Note how much higher these are than the workplace exposure limit for respirable crystalline silica (0.1 mg/m³) covered in Section 4.2 — but unlike silica, lead also has a biological monitoring regime, because air sampling alone does not capture the ingestion route.

Significant exposure

Exposure is treated as significant — triggering the full regime including medical surveillance — where any of the following applies: air concentration exceeds half the occupational exposure limit; there is a substantial risk of ingestion; or there is a risk of skin contact with a readily absorbed form such as a lead alkyl. The "half the limit" trigger is easy to miss: you can be well inside the legal air limit and still be required to place workers under surveillance.

Blood-lead action and suspension levels

Biological monitoring measures blood-lead concentration in micrograms per decilitre (µg/dl). Two thresholds matter, and they differ by worker group:

The action level is a management trigger, not a limit: the employer must immediately determine why the level rose, review the controls, and take steps to bring it down. The suspension level is a medical decision by the appointed doctor to remove the worker from lead work entirely.

Women of reproductive capacity have the lowest thresholds because lead crosses the placenta and is a reproductive toxin. CLAW also restricts the employment of young persons and women of reproductive capacity in certain high-exposure lead processes.

Appointed doctors must report blood-lead results and any suspensions to HSE annually, and health records must be kept for 40 years — the same retention period as for asbestos and other long-latency exposures.

A change on the horizon — but not yet in force

HSE has been consulting on substantially lowering these thresholds, on the evidence that harm occurs well below the 2002 figures — effects on blood, nervous system and kidneys have been observed above 40 µg/dl, and raised blood pressure in middle-aged men around 30 µg/dl. Proposals discussed have included staged reductions of the general suspension level from 60 µg/dl towards 30 and then 15 µg/dl, with corresponding reductions in action levels and a much lower threshold for workers capable of conceiving. None of this is law yet. For examination and site purposes, the figures in the table above are the ones currently in force under CLAW 2002. This is a good illustration of the SMSTS habit of checking whether a rule you have heard about is actually in force or merely proposed.

Practical Site Controls for the Common Case

The single most common construction lead scenario is removing or disturbing old paint during refurbishment. The control decision follows the hierarchy:

• Eliminate: leave sound, intact lead paint in place and overcoat it, or remove the whole component off site for controlled treatment.
• Substitute the method: chemical or infrared paint removal generates neither fume nor fine dust, unlike burning, blasting or dry sanding. Choosing the method is a design and planning decision that belongs in the risk assessment, not a decision for the operative with the hot air gun.
• Engineer: on-tool extraction fitted with an H-class filter (as covered for silica in Section 4.2), full enclosure with negative pressure for large-scale removal, and wet methods where compatible with the substrate.
• Administrative: restrict access, exclude non-essential workers, prohibit eating and smoking, enforce hand washing before every break, and use disposable coveralls and a designated changing area.
• RPE last: face-fit tested, with the assigned protection factor matched to the measured or predicted exposure.

The manager's test question when a refurbishment method statement lands on the desk is simple: does this method heat or abrade a surface that may contain lead, and if so where is the CLAW assessment? If the answer is silence, the work does not start.