​​1. INTRODUCTION

There are a number of circumstances where STFC staff may come into contact with lead (Pb) in the course of their work. These mostly relate to:

• areas where solid elemental lead is used as shielding to restrict exposure to ionising radiation, or where used as weatherproofing on buildings
• work on lead or the use of lead-based solder during fabrication
• removal or repair of lead-based paint during building refurbishments
• repairs or modifications to old lead pipework and mechanical or electrical services
• lead in lead-acid batteries
• lead in soil (usually as contamination from former processes or disposals)
• organic lead compounds such as lead alkyls or naphthenate.

Lead, including its compounds, is a substance that has long been known to have the potential to damage health. The Control of Lead at Work Regulations (CLAW) 2002 place a number of duties on employers to:

1. protect the health of people at work by preventing or, if not reasonably practicable, by adequately controlling their exposure to lead; and
2. monitor the amount of lead that employees absorb so that individuals whose work involves significant exposure (as defined by the Regulations) to lead at work can be redeployed before their health is affected.​

2. ROUTES OF ENTRY AND SIGNIFICANT EXPOSURES

Exposure may occur where elemental lead, lead alloys or lead compounds enter the body by three principal routes, thereby causing adverse health effects:

• ingestion (e.g. lead powder, dust, paint or paste)
• skin absorption (e.g. lead alkyls or lead naphthenate)
• inhalation (e.g. lead dust, fume or vapour)

If there is a substantial risk of the employee ingesting it; or if there is a high risk of skin contact with lead alkyls or substances containing lead which can be absorbed through the skin, exposure may be significant.

Exposure to lead via the inhalation route is also considered to be significant if exposure exceeds half the occupational exposure limit (OEL) for lead in the atmosphere to which any employee is exposed. This means:

1. a concentration of 0.15 mg/m3 of lead (other than lead alkyls);
2. a concentration of 0.10 mg/m3 of lead contained in lead alkyls.

The OELs for lead have been established by atmospheric monitoring over an 8-hour time-weighted average (TWA) reference period, which reflects a standard 8-hour shift. (Shorter sampling periods are possible and the results can be extrapolated, provided the sampling period is representative of a normal working exposure.)

However, there is no direct relationship between the amount of lead the body absorbs and the concentration of lead in the atmosphere and employees whose exposure is assessed as being significant, must be placed under medical surveillance. Regular biological monitoring of the level of the lead in their blood or urine (for work with lead alkyls) can detect any absorption of lead before clinical effects become evident. Biological monitoring helps employers evaluate the effectiveness of their control measures in keeping lead in blood or urine levels at acceptable concentrations.

3. WORK WITH LEAD AT STFC

The Approved Code of Practice (ACoP) for work with lead (L132) has a simple flow chart which can help with assessing requirements under the CLAW Regulations. It also lists the types of activity with lead which may present a risk of significant exposure, and where the detailed requirements of CLAW must be applied.

A copy of the ACoP can be downloaded free from the HSE​.

However, the general activities involving the use of lead at STFC, as described in section 1, above, are unlikely to result in significant exposures, providing sensible precautions and good hygiene practices are followed.

The principles of exposure control applied to hazardous substance use under the COSHH Regulations will generally also satisfy CLAW for STFC’s use of lead.

All work with lead should be assessed using the STFC COSHH assessment template. If the COSHH assessment indicates that the precautions provided in the guidance are likely to be ineffective in controlling exposure to lead, by any potential exposure route, resulting in a potentially significant exposure then the SHE Group must be consulted.

4. CONTRACTORS WORKING AT STFC

Where external contractors are employed to work with lead, their risk assessment must also include consideration of the potential lead exposure of STFC employees in the vicinity of their activities.

All STFC staff coordinating or managing such contractors (for example Project Managers and Contract Supervising Officers) must review their contractors’ risk assessment and method statements (RAMS) to ensure that that these risks are adequately considered, and that all lead-exposure control measures are clearly detailed.

A hierarchical approach to control measures must be applied, with avoidance of the activity being the best strategy. If the work cannot be avoided then the approach should be to restrict the activity to a specified time thereby minimising the number of persons potentially exposed, for example restricting the work with lead to weekends.​

5. GUIDANCE

The following guidance is intended to minimise worker exposure to, and environmental contamination from, lead. In this context ‘lead work’ is any work activity where lead is handled, processed, repaired, maintained, stored or disposed of, and includes:

• Handling or stacking lead bricks
• Disposing of legacy lead
• Machining lead (cutting, shaping, or finishing lead materials using powered tools)
• Welding or torch soldering on lead material (including leaded pipes)
• Using lead-containing solder
• Grinding, sanding, wire brushing, or otherwise abrading lead-containing paint
• The use of heat guns to remove old lead paint
• Vehicle maintenance (including FLTs) and disposal of damaged lead batteries (which also contain other corrosive hazardous substances).

5 (a) Routes of Entry and their Control Measures

The relative contribution of each activity to an individual’s potential lead exposure will vary according to the form in which the lead is being used, and the way in which it is being handled or machined.

The principal exposure routes for the activities undertaken at STFC are considered to be by inhalation or ingestion, and much less so via the skin, unless the skin is broken or the lead is carried through the skin’s protective oily barrier in organic lead compounds. However, the following control measures for specific activities should address the potential for exposure to lead by all routes.

5 (b) Lead Brick Shielding and Lead Sheeting

Inhalation

1. Newly purchased lead bricks should be doped with Antimony (Sb) at 4% w/w, to harden the lead and lessen surface oxidisation.
2. Lead bricks should be stored in dry conditions, and not kept in the open where they are susceptible to the elements. If stored outside they should be protected from the weather.
3. Lead bricks should ideally be surface coated or painted to prevent further surface oxidisation, as this has the potential to generate dust when blocks are handled.
4. Lead bricks must be handled and placed carefully to avoid surface damage and release of lead particles, and once structures have been built, work areas must be wiped down.
5. If lead bricks remain unpainted then the external surface of the assembled shielding structure should be protected (by use of plastic sheeting or similar) to prevent accidental surface damage or abrasion during routine work, which has the potential to generate dust.
6. Respiratory Protective Equipment (RPE), with FFP3 particulate filters, should be worn when assembling or disassembling uncoated lead shielding which is within the worker’s breathing zone.
7. Respirators must be tight fitting and fit tested.
8. Reusable respirators must be cleaned after use, and stored to prevent contamination (in a plastic zip-lock bag, for example). Reusable respirators must be checked and ‘maintained’ (a check of the seals, valves and straps, for example) to ensure an effective seal to the user’s face and continued user protection.
   Disposable respirators must be disposed of at the end of each work period (they are intended to be single use).
9. The machining of lead bricks or lead sheeting using a powered tools such as milling machines, drills, etc, should only be undertaken in designated areas, and precautions taken to wet down to prevent dust / debris generation.
10. Machine tools and bits should be cleaned with dampened disposable paper towels after use.
11. Lubricants and cutting oils used for machining lead should be changed frequently and disposed of as lead-containing waste.
12. Lead and lead-contaminated dust must be cleaned up carefully, by wet wiping only, to avoid raising dust.
13. All surfaces and bench tops must be kept as free as practicable from any accumulation of lead dust or debris.
14. Domestic vacuum cleaners may not be used.
15. Compressed air lines may not be used to clean dust laden surfaces.
16. Only the following cleaning methods are allowed:
    1. Vacuum cleaners must be equipped with a high-efficiency particulate air (HEPA) filters, and labelled ‘for lead clean up only’. When replacing the filter it must be removed carefully without releasing dust and the filter sealed in a plastic bag for disposal as lead-containing waste.
    2. Wet wiping surfaces with disposable wet paper towels. Dry sweeping of lead debris is not permitted.
    3. Lead dust on floors may be wet mopped. However, the mop head must be kept separate and labelled ‘for lead clean up only’.

NOTE: Due to the high surface area associated with lead wool and the tendency for significant surface oxidation and potential for dust generation and deposition, its use is strongly discouraged and must be justified in a COSHH assessment.​

Absorption through skin

1. When handling lead bricks workers should be double gloved. A pair of disposable gloves should be worn underneath non-absorbent and non-permeable work gloves.
2. Reusable work gloves used for handling lead must be only be used for this purpose and not for any other activity. Leather gloves should be avoided as they are relatively permeable and lead dust can accumulate on them.
3. Once removed these gloves should be placed in a plastic zip-lock bag, or similar, and labelled ‘for lead handling only’. They must be separately packaged from reusable respirators which are used for lead work.
4. Disposable gloves should be changed regularly, and when damaged, and at the end of each handling period they must be disposed of promptly and not left lying around.
5. Coveralls, if worn during lengthy periods of handling, should be of the disposable type to avoid contaminating washing machines or other clothing, and disposed of at the end of each work period.

Ingestion

1. Wash hands, and face, immediately after working with lead, or disposing of lead contaminated materials.
2. In areas where there is no ready access to soap and water hand wipes should be made available for cleaning hands. However, washing with soap and water should be undertaken as soon as practicable.
3. Never eat, drink (smoke or vape) in, or around, areas where lead is handled or stored.
4. Food or drink must never be stored in an area where lead work is undertaken.

These general principles apply for ALL work with elemental lead and lead-containing materials, however additional precautions may apply in the following cases:

5 (c) Working on Leaded Paint

The age of many of STFC’s buildings means that lead paint may have been used (typically on surfaces in pre-1960 buildings, and in some up to the 1980s). Painted woodwork, particularly on or around windows and doors, must therefore be treated with caution and not dry sanded. However, in older buildings other painted surfaces may potentially contain lead and should also be treated with caution.

1. If paint is in good condition, it may be overpainted and sealed with a new coat. However, if paint is flaking and in otherwise poor condition, then removal is the best option. Consideration should be given to chemical paint removal, rather than dry sanding, providing this does not introduce additional risks.
   NOTE: Such use of chemical agents is subject to further COSHH assessment.
2. ​Only heat guns operating below 500°C​ should be used to heat-strip old paint, to avoid generating lead fumes which can be inhaled.
   
3. If paintwork must be sanded, only wet sanding techniques should be used, and all dust slurry must be wet-wiped immediately.
4. Disposable gloves should be worn and changed frequently, or when damaged, and at the end of each work period they must be disposed of promptly.
5. Respiratory Protective Equipment (RPE), should be worn, which is tight fitting and fit tested, with filtration to FFP3.
6. The cleaning and maintenance requirements for RPE, as highlighted above in Section 5(b), also apply.
7. The controls highlighted above for ingestion (and skin absorption) exposure routes must also be applied, as do the arrangements for cleaning up when work is complete, and for waste disposal.
   

5 (d) Lead in Piped Services, on Electrical Cables or in Building Fabric

1. Avoid hot cutting lead pipes during repair and / or dismantling of old pipework, consider other work methods such as cold / mechanical cutting where practicable. Mechanical methods must take account of the potential to generate lead dust and therefore dust suppression measures applied.
2. Avoid surface abrasion of lead-containing cables or lead pipework as far as possible.
3. When working on any lead pipes disposable gloves, and ideally coveralls, should be worn and discarded at the end of the job.
4. Respiratory Protective Equipment (RPE), must be worn where there is a risk of either lead fume or lead dust generation, and this must be tight fitting and fit tested, with filtration to FFP3.
5. The cleaning and maintenance requirements for RPE, as highlighted above, also apply.
6. The hygiene controls highlighted above to prevent lead exposure by ingestion and skin absorption must also be applied, as do the arrangements for cleaning up when work is complete, and for hazardous waste disposal.​
   

5 (e) Lead Solder and Solder Flux

During soldering lead fumes are generated, which are toxic. For this reason lead-free solders should be substituted for lead wherever possible. However, lead-free alternatives are often considered to be technically inferior to leaded solders, for both soldering and for certain applications e.g. electrical properties and long term reliability of circuits.

Where leaded solder is absolutely required then suitable extraction must be provided to prevent personal exposure to lead fumes and workplace contamination.

Certain fluxes used for soldering also emit fumes, which are hazardous by inhalation. Acid flux types may contain hydrochloric acid, zinc chloride or ammonium chloride, which are harmful to humans. Prolonged exposure to colophony (or rosin) fumes released during soldering can cause occupational asthma .

As well as inhalation hazards there are also skin hazards. While molten solder has low tendency to adhere to organic materials, molten fluxes, especially of the rosin type, adhere well to fingers, in a manner similar to hot glue, rapidly transferring heat to the skin with potential to cause serious burns. Skin protection is required.

1. Alternatives to the use of lead solder should be sought, and if they are unsuitable for a particular task the continued use of lead solder must be robustly justified in the relevant COSHH assessment.
2. Alternatives to rosin-based fluxes must also be sourced and, as above, recorded in the COSHH assessment (or justification provided where this is not possible).
3. Solder stations should be demarcated wherever possible, for example by the use of tape or signage, to prevent the potential spread of lead contamination.
4. Suitable separate storage for lead solder and fluxes must be provided (e.g. a lockable cupboard).
5. Work benches must be regularly wet-wiped to remove lead / flux dust or debris.
6. Local Exhaust Ventilation (LEV) must be used, either as on-tip extraction or by use of a mobile capture hood, as a control for the inhalation hazard.
7. LEV must be registered with SHE Group for statutory testing, and maintained in accordance with manufacturer’s recommendations, as a minimum.
8. The controls highlighted above for ingestion and skin absorption must also be applied.​
   

5 (f) Organic Lead Compounds

The principal route of entry for organic lead compounds is via skin absorption. Gloves must be carefully selected to take account of relevant breakthrough times during handling, and the selection must be specified in the relevant COSHH assessment. Gloves must be changed frequently and whenever damaged.

5 (g) Lead Batteries

Lead batteries obviously contain lead, which is generally contained unless the battery is damaged. Although exposure is unlikely, the principal route of entry to the body in this case is by ingestion and good hygiene practice will adequately control an individual’s exposure to it. Batteries may also contain acid and during handling precautions must be taken to protect the eyes and skin (wearing safety spectacles or full face visors, and appropriate hand / arm protection) from the corrosive action of battery acid.​

5 (f) Waste Management

1. Lead-contaminated waste (for example wetted paper towels, wet wipes, disposable PPE, etc) is unlikely to exceed threshold limits for disposal in the ‘domestic’ waste stream and may therefore be disposed of in normal black bag waste.
2. However, if a significant quantity of such lead-contaminated waste is generated on a regular basis, a designated container must be provided. Such waste may require disposal as hazardous waste, and further advice should be sought from the SHE Group.
3. Old / oxidised / unwanted lead bricks must be disposed of either as hazardous waste, or returned to the supplier where they may be reprocessed and resold. Old lead bricks must not be used as door stops, props or for other inappropriate purposes.
4. Lubricants, cutting oils and other wetting agents used for machining lead should be disposed of as lead-containing waste, via the hazardous waste disposal route.
5. Old lead batteries should be disposed of as hazardous waste.

5 (g) Other non-lead hazards

1. When building or relocating lead shielding bricks (or moving old lead pipework, or handling batteries) one other significant hazard relates to manual handling. For example, although lead bricks may vary in size to some degree, typically they weigh in the region of 2.2 kg each, with potential for injury due to the repetitive nature of the task.
2. Lead bricks should be handled, one brick at a time, using both hands. Good lifting technique should be applied.
3. In addition to the other PPE and RPE requirements, protective footwear should be worn, i.e. safety-toed shoes or boots.

Further information may be found in Safety Code 12 - Safe manual handling​.

5 (i) Health Surveillance

Implementation of the precautions listed should ensure that there is no significant occupational exposure to lead and health surveillance is not required.

However, in relation to the use of colophony, a cause of occupational asthma (if this cannot be substituted for a suitable alternative and is justified in the COSHH assessment), may require relevant individuals to be registered with STFC’s Occupational Health provider for a health surveillance programme. A review of all relevant control measures would be required to determine whether this is necessary.

The HSE document INDG305 "Lead and You" also has basic information for those working with lead.