Managing Lead and Mercury Exposure During Refurbishment Works

The Challenge

During refurbishment works involving the removal of parquet flooring and door frames, concerns were raised regarding potential exposure to lead-containing dust and mercury vapour. Both substances pose serious health risks, particularly during disturbance of legacy building materials.

Independent occupational hygiene support was required to:

• Assess airborne concentrations of lead and mercury.
• Determine whether Workplace Exposure Limits (WELs) were being approached or exceeded.
• Provide clear guidance on appropriate PPE and RPE requirements.
• Reassure operatives, visitors and duty holders that risks were being properly managed.

The Approach

Sysco Environmental carried out a structured metal air monitoring programme in accordance with HSG 248 and MDHS 14/4.

The scope of works included:

• Static air monitoring across multiple floors where removal activities were taking place.
• Separate analysis for lead in airborne dust and mercury vapour.
• Sampling undertaken during normal working activities to reflect realistic exposure conditions.
• Laboratory analysis using validated methods, with results corrected for blanks and flow rates.
• Interpretation of results against EH40 Workplace Exposure Limits.

Environmental conditions and site activities were recorded to ensure results were representative and defensible.

The Findings

The monitoring programme identified a clear distinction between the two metals assessed:

Lead:

• Airborne lead concentrations were below 0.015 mg/m³, representing less than 10% of the WEL.
• Exposure to lead-containing dust was assessed as very low risk under the conditions monitored.
  
  Mercury:
• Airborne mercury concentrations ranged from below detection to approximately 0.08 mg/m³.
• In certain areas, results exceeded the WEL of 0.02 mg/m³.
• This indicated a credible risk of over-exposure during routine activities in specific locations.

The findings confirmed that while lead exposure was well controlled, mercury presented a significant occupational health risk without additional controls.

The Recommendations

Based on the results, Sysco Environmental provided clear, task-specific recommendations, including:

• Mandatory use of appropriate PPE and RPE in areas where mercury vapour exceeded the WEL. Including coveralls, gloves, eye protection and full-face masks or PAPRs with ABEKHgP3 filters.
• Strict controls on contaminated waste disposal, including clothing, filters and cleaning materials.
• Enhanced personal hygiene measures, including handwashing and prohibition of eating in affected areas.
• Cleaning of tools and surfaces using damp methods to prevent re-suspension of contaminants.
• Restricting access to areas where elevated mercury concentrations were identified until controls were in place. 

The Outcome

The assessment provided:

• Clear, evidence-based confirmation that lead exposure was not a concern.
• Early identification of mercury exposure risks, preventing uncontrolled over-exposure.
• Practical guidance enabling the correct level of protection to be implemented immediately.
• Reassurance to duty holders that risks were understood, measured and appropriately controlled.

Most importantly, the monitoring ensured that worker and visitor health was protected, even in a complex refurbishment environment involving legacy materials.

Why This Matters

Metal exposure risks during refurbishment are often hidden until materials are disturbed. This case study highlights the importance of targeted occupational hygiene monitoring — not just to confirm when risks are low, but to identify and control serious hazards before harm occurs.