SIM 03/2011/01
A Cathode Ray Tube (CRT) unit is the part of a computer or TV monitor consisting of two different types of glass (see Figure 1). Televisions and monitors that are based on CRT technology are increasingly being replaced by flat-screen TVs that use LCD (liquid crystal display) or plasma screens resulting in an increasing amount of CRTs in the waste stream. CRTs contain heavy metals including lead. In addition to the glass, there are other materials to be recycled including ferrous and non ferrous metals, coatings (typically a mixture phosphors and aluminium oxides) to the screen and funnel sections, and plastic housing casings.
The viewing section (known as screen, panel or face plate) is made of glass, typically containing a significant level of barium oxide but no lead oxide.
Both the funnel glass and the neck glass contain lead oxide. The funnel section contains up to 25% lead oxide. The neck section, housing the electron gun, is up to 40% lead oxide. The three glass components are joined together using a low melting temperature solder glass that also contains high levels of lead oxide (up to 60%).
The primary health risk from the separation and process of the CRT glass components is personal and environmental exposure to lead dust despite the presence of other chemicals, such as those found in the coatings. As such this inspection commentary concentrates primarily on the control of exposure to lead. However if this exposure is properly controlled then the control of exposure to other substances should also be adequate.
For example, personal exposure to lead has been recorded up to twenty times the occupational exposure limit in semi automatic sawing processes (see below) whilst secondary exposure to phosphor coating and aluminium oxide was half the respective workplace exposure limits.
The recycling of CRTs can be broken down into a number of discrete stages: receipt, initial dismantling and treatment of the glass components (see Figure 2).
TV and computer monitors are collected from a number of sources including public amenity sites, private individuals, and private companies. TVs and computer monitors in good condition are often put through a test regime to determine if they are suitable for refurbishment or resale outside of the European Community (EC). These are stored on site to be moved on and sold.
The TV/computer monitors are delivered to recycling sites in vehicles ranging from panel vans to articulated lorries. Many TV/computer monitors arrive at the recycling centres damaged, with broken screens being common. TV/computer monitors are typically transported by hand to the recycling line or the load tipped adjacent to the recycling line.
Typically TV/computer monitors are transported for dismantling via roller or belt conveyors and the dismantling activity takes place on open work benches (see Photograph 1). The plastic outer cases and other components (outer cases, wiring looms, transformers and printed circuit boards) are removed by hand. Removed items are typically stored on site prior to further processing. The plastic has an intrinsic value and maybe be processed on site (granulated) or intact cases dispatch to other companies for further processing.
At this stage the glass CRT assembly has been moved down the recycling line to be processed separately, typically by separating the panel from the funnel.
The inside of the screen panel is coated with a mixture of phosphors and a layer of aluminium oxides. The funnel section has an outer coating of graphite and an inner coating of iron oxide and there is a metal screen (shadow mask). At this stage the electron gun assembly is still in situ and the screen will be surrounded by an anti implosion metal band.
The first action is to remove the electron gun assembly which is attached to the neck of the funnel section. This is removed by hand by tapping the assembly with a hammer. The electron gun assembly is stored for further processing.
The next stage typically involves the separation of the screen panel from the funnel. A variety of separation methods have been observed for this.
Photograph 2 shows a manual separation process with an open faced recirculation extraction booth. In this example measurement of exposure showed personal exposure to lead by inhalation to be ten times the occupational exposure limit (OEL). The booth had not been subject to a thorough examination and test and did not offer adequate extraction.
Prior to the separation of the glass component’s the anti implosion band is removed by a mechanical cutting tool. If a saw is used to score the glass prior to separation, the score line is made inside of the frit line on the panel side of the joint thereby ensuring that the panel glass is lead free. Once separated the metal shadow mask is removed for further processing and the phosphor coating is removed by manual vacuuming.
NB: The phosphor coating is required to be removed as part of the licensing requirements placed upon companies by the Environment Agency.
Photograph 3 shows an example of a semi automatic sawing process carried out in ventilated enclosure. Although the ventilation was found to be effective the process design was found to be flawed due to insufficient clearance time. Operators were required to manipulate the work piece to the complete separation. A visible dust cloud indicates a high level of lead in air (e.g. 20 times lead in air OEL).
Photograph 4 shows an open face downdraught booth. These can be effective. However, in this example observations found that the filters had become blocked leading to greatly reduced performance resulting in three times the lead in air OEL). The extraction systems were fitted with air flow indicator devices (red indicating poor operation requiring maintenance/change of filters) but poor systems of work meant the required maintenance wasn’t carried out.
Photograph 5 shows an example of a hot wire separation machine. A single wire is, either manually or mechanically, wrapped around the panel. The wire is then heated electrically for approximately one minute. Following this a short blast of cold air is used to thermally shock the glass to aid separation.
Following separation the glass may be then be further processed by washing and/or breaking up using a trommel. The different glass may be washed separately or combined as a mixed glass. Washing removes the phosphor coating, lining the inside of the screen. The action of the rotating washer breaks the glass up into smaller pieces (see Photograph 6).
Following processing, leaded glass, unleaded glass or mixed glass is bulk stored prior to dispatch to customers. The panel glass can be used as an aggregate or can be exported to manufacture new panel glass. Funnel glass can be exported to make new panel glass. It is not suitable for use as an aggregate (unless de-leaded).
Lead is a silver grey, very soft and malleable metal. When inhaled (more important route for occupational exposures) or ingested as dust, aerosol, fume and vapour, the degree of absorption is dependent on particle size and solubility. The percentage of inhaled lead reaching the bloodstream is estimated to be 30 to 40 percent. Inorganic lead is not absorbed through the skin. Once absorbed, lead binds strongly to red blood cells, and is then deposited in bone, teeth, liver, lungs, kidneys, brain and spleen, where it accumulates, reaching the highest concentrations in bone.
Although lead is excreted by several routes (including sweat and nails), only the renal and gastrointestinal pathways are of practical importance. In general, lead is excreted quite slowly from the body (with the biologic half-life estimated at 10 years). Since excretion is slow, accumulation in the body occurs easily. The lead that accumulates in the bone ultimately provides a source for remobilisation and continued toxicity after exposure.
Lead exposure can cause damage to the brain, organs, and nervous system and even at low levels it can cause irreversible damage without causing symptoms.
Lead exposure can cause:
| Weakness | poor concentration and memory |
| Anaemia | abdominal pain, nausea, poor appetite |
| weight loss | constipation |
| Fatigue | sore muscles |
| headaches | kidney damage |
| difficulty sleeping | nervous system effects |
| Depression | reproductive problems |
Lead can be passed from mothers to their unborn children and can cause miscarriages and premature births. In an infant, lead exposure can cause permanent cognitive impairment, behavioural disorders, and developmental delays.
In addition to its acute and chronic poisoning effects, lead is classified as ‘probably carcinogenic to humans (Group 2A)’ by The World Health Organization (WHO) International Agency for research on Cancer (IARC) though it does not have an EU classification for cancer yet.
The occupational exposure limits (OEL) for lead in the atmosphere are set out in the Control of Lead at Work Regulations 2002 (CLAW). The limits are 8-hour TWA concentrations as follows:
The Regulations also refer to "significant exposure" to lead. This is defined in Regulation 2 as exposure where any employee is, or is liable to be, exposed to a concentration of lead in the atmosphere exceeding half the OEL for lead. Therefore, significant exposure to lead (other than lead alkyls) corresponds to anything greater than 0.075 mg/m3. An employee may also be significantly exposed where there is a substantial risk of any employee ingesting lead. If exposure is significant, the employer must monitor lead-in-air concentrations and provide the exposed employee with suitable and sufficient protective clothing and place the employees concerned under medical surveillance (discussed below).
Currently there are no UK standards set for levels of surface contamination for lead. However, for comparison only, in 2001 the United States (US) Environmental Protection Agency (EPA) published limits, based on wipe sampling, identifying hazardous levels of dust in public housing occupied by children. They are:
Also for comparison, HSL suggest that Portable X-Ray Fluorescence (PXRF) results:
The Control of Lead at Work (CLAW) Regulations 2002 places a number of duties on employers who carry out work which is liable to expose employees to lead. These include:
Employers should inform employees if their exposure to lead is ‘significant’. If it is, the employer has a duty to:
The Control of Substances Hazardous to Health (COSHH) Regulations 2002 (as amended) also imposes duties on employers to assess the risks to health arising from exposure to hazardous substances and to ensure that exposure to these substances is prevented or, where this is not reasonably practicable, adequately controlled. These requirements will cover many of the substances other than lead contained in the CRTs.
It is necessary to carry out a suitable and sufficient COSHH risk assessment (Regulation 6). The assessment should be used to determine the measures to prevent or control exposure to other hazardous substances that may be airborne other than lead.
Where it is ‘reasonably practicable’ (i.e. the costs in reducing exposure would not be grossly disproportionate to the benefits) COSHH requires the prevention of exposure to substances hazardous to health. This can be achieved by changing the process so that the substance is no longer used and/or produced; replacing it with a safer alternative or completely enclosing the process.
The principles of good occupational hygiene practice as outlined in COSHH Schedule 2A Regulation 7(7) for the control of exposure to substances hazardous to health should be applied to achieve control below any relevant Workplace Exposure Limits (WELs) for those substances in air or for those substances not assigned a WEL to a level which nearly all the working population could be exposed, day after day at work, without adverse affects to health.
NB: It is expected that if exposure to lead is well controlled then exposure to other inhalable dust and component substances should also be adequately controlled.
As outlined above under the Control of Lead at Work Regulations 2002 duty holders should be able to demonstrate that they are managing the risks of exposure to lead in CRT recycling. They should have:
NB: Similar provisions are also contained within the Control of Substances Hazardous to Health Regulations with respect to other hazardous substances.
Each company should have carried out a suitable and sufficient assessment of the exposure to lead in the CRT recycling process.
The assessment should include details on the number of workers likely to be exposed to lead during the overall recycling process, the length of time of the potential exposure and a description of the measures used by the company to prevent or control lead exposure.
The OELs for lead relate to a workers personal exposure to lead in air. The measurement of exposure will normally involve the collection of a sample of air from the employee’s breathing zone using personal sampling equipment and techniques.
The monitoring shall be carried out at least every 3 months – it can be increased to a maximum of 12 months where there has been no material or work change since the last occasion of monitoring and if the lead in air concentration for each group of employees or work area has not exceeded 0.10 mg/m3 on the two previous consecutive occasions on which monitoring was carried out.
The risk of poisoning increases with the absorption of lead and lead compounds into the body. Biological monitoring of lead workers is a tool for assessing the uptake of lead and can indicate those who are at risk of lead poisoning. The Control of Lead at Work Regulations 2002 requires that medical surveillance, including biological monitoring, be carried out on employees where exposure is ‘significant’ (see under Health Surveillance below).
The duty in Regulation 6(2) to prevent exposure should be achieved by measures other than the use of personal protective equipment. In the first instance, employers can comply with this requirement by eliminating completely the use or production of lead in the workplace. This might be achieved by:
Where prevention of exposure to lead is not reasonably practicable (such as in recycling processes) employers must comply with the secondary duty to adequately control exposure. Adequate control of exposure to lead should be achieved with measures other than the use of PPE which should only be used as a last resort and then in addition to other control measures.
The processes used to recycle CRTs vary from company to company. It might involve dismantling of the CRTs and processing of the glass components or alternatively processing of the glass components only. However, they should all be designed to ensure that exposure to lead is either prevented or as low as reasonably practicable at all stages. This can be achieved for example, by totally enclosing process and handling systems, partially enclosing the process where possible to reduce the release of contaminants by the use of effective LEV at the contaminant source, appropriate organisational measures by designing the work methods to minimise the number of exposed operatives.
It may not always be necessary to apply all the controls described above but it will be necessary to use a combination of them. The employers aim should be to select those control measures which in practice will work best to protect the health of employees. The employer should give priority to those controls that contain or minimise the release of contaminants. Administrative and procedural options for control are also important elements which the employer should consider.
The CRTs should be handled carefully to prevent accidental damage and the subsequent release of lead. Sufficient general ventilation should be provided and where appropriate to provide make-up air for the installed LEV system(s).
If total enclosure is not reasonably practicable effective and efficient LEV should be designed and installed to minimise exposure to lead. Partial enclosures, such as booths, which enclose the lead at source and prevent its escape outside the enclosure by using an exhaust draughts, are preferable. If not reasonably practicable the LEV capturing hood should be of such a size so as to contain and extract the contaminant as near as practicable to the point of source. The hood should be positioned to take advantage of the speed and direction of the airflow from the contaminant source. The ductwork should have an airflow that is adequate to carry away the contaminant. The design of the hood should be such that is consistent with the way the operatives handle the CRTs.
The LEV system needs to have a dust and or/fume collection unit with necessary filtration equipment. Preferably, filtered air from the exhaust system should not be returned to the workplace. If it is returned back into the workplace the employer’s risk assessment must demonstrate that there is no significant additional risk to employee’s health. To ensure, this employers should:
High efficiency filtration will usually mean using fabric filters more than 99% efficient, with facilities for monitoring filter performance and detecting filter failure.
Preferably filtered air from the exhaust system(s) should not be returned to the workplace. If it is, the employer’s assessment must demonstrate that there is no significant additional risk to the employee’s health..
The performance of the LEV systems should be checked regularly (daily, weekly and monthly) to ensure that they are controlling lead exposure efficiently and effectively. Airflow indicators can be fitted to a LEV system to indicate that there has been no pressure drop and that it is working effectively.
The LEV systems should be thoroughly examined and tested at least once every 14 months. Records should be kept of the results.
Protective clothing should help achieve control of lead dust/fume/vapour by protecting personal clothing and the body from being contaminated by lead. It also helps prevent the spread of lead by reducing the chance of contaminated clothing being taken home. For protective clothing to be suitable and adequate it must be appropriate for the work concerned and the conditions where exposure to lead my occur and cover all parts of the employees’ own clothing, and so far as is reasonably practicable, effectively resist penetration by lead in the form of dust/fume/vapour and protect the employee’s own clothing. It is expected that operatives should wear overalls, safety glasses, gloves, safety boots or shoes and hearing protection and High-Viz jacket (replaced regularly).
CLAW imposes a hierarchy of control measures and indicates that RPE should always be regarded as the final step in the control regime to protect workers. Suitable RPE should be worn where there is the potential for lead exposure e.g. during the glass component recycling stage. At this stage it may not be feasible to solely achieve adequate control with a LEV system so suitable RPE should be used in addition to secure adequate control. It is important that the RPE filter(s) (P3 particulate filter) used provide adequate protection from lead exposure. The filters should be changed regularly.
Operatives wearing tight-fitting RPE should have been fit tested. HSE recommends that the maximum wear time for tight fitting RPE is one hour. If tasks are likely to exceed this time then RPE should be worn that does not rely on a tight fit for example, using a powered (fan-assisted) respirator with a visor and appropriate P3 particulate filters.
The RPE (including PPE) should be well maintained and correctly used – employees should be properly trained in its use and supervised. This is to ensure that the equipment continues to provide the degree of protection for which it was designed. Maintenance includes cleaning, disinfection, examination, repair, testing, safe storage and record keeping.
Where possible, the CRT processing should be in a segregated area and within easy access of washing facilities and changing areas. The workers should clean and wash their hands with soap and water after handling the CRTs and immediately if their skin becomes contaminated.
There should be adequate facilities for workers to change, remove and store their PPE/RPE e.g. provision of clean and dirty areas with lockers or coat hooks. The changing facilities should contain adequate washing facilities. The company should provide laundry facilities for contaminated overalls to be cleaned.
A high standard of personal hygiene plays a crucial role in controlling lead absorption. Suitable and sufficient washing facilities, including showers where appropriate, are required by Regulation 21 of the Workplace (Health, Safety and Welfare) Regulations 1992. This is an important requirement for those exposed to lead at work. Also, lead can be easily absorbed through ingestion.
To avoid this risk, the Regulations impose duties on employers to make sure that employees do not eat, drink or smoke in any place which is liable to be contaminated by lead. To emphasise the importance of this aspect of controlling exposure, the Regulations also place a duty on employees not to eat, drink or smoke in places which they believe may be contaminated by lead. There should be no eating and drinking in the CRT processing areas. Food and drink should not be stored in the work areas. No one should enter the canteen/mess room areas until they have removed dirty overalls and have washed their hands.
In laying out their facilities, the employer’s aims should be to ensure that they can be conveniently used, and to minimise the spread of contamination. To help achieve these objectives, employers should:
Design features are also important in helping to prevent lead contamination. Walls, ceilings, floors, washbasins, baths and showers should have smooth impervious surfaces which can be easily washed or cleaned and which cannot trap lead and dirt in corners and crevices. Smooth painted washable surfaces, ceramic surfaces and stainless steel surfaces are all suitable.
There should be good housekeeping (e.g. cleaning of wash basins, toilets, changing facilities, the canteen area) to reduce surface contamination.
Regular cleaning and or collection of spillages should so far as reasonably practicable, only be carried out by non dust generating methods e.g. use of wet cleaning methods or use of vacuum cleaner fitted with High Efficiency Particulate Arrestor (HEPA) filters.
There should be appropriate supervision to ensure that workers are following good practice and procedures at all times.
Where exposure to lead is significant, as defined in Regulation 2 Control of Lead at Work Regulations 2002, the employer should ensure that the employee is under medical surveillance by either a medical inspector or an appointed doctor. Where a doctor is of the opinion that work practices, welfare facilities or where an individual’s personal hygiene is poor they may place an employee/s under medical surveillance even if they are not significantly exposed to lead (Regulation 10).
Medical surveillance should be carried out by a HM Medical Inspector or by a doctor appointed by HSE. Guidance notes for Appointed Doctors are included in Appendix 5 of the Regulations. The purpose of the surveillance is:
The surveillance consists of an initial assessment and periodic medical assessments determined by the Appointed Doctor to be carried out at least annually.
The initial assessment should be carried out preferably prior to exposure to work involving exposure to lead. As part of the assessment the Appointed Doctor will:
The Control of Lead at Work Regulations 2002 requires that biological monitoring is undertaken as part of the medical assessment. The risk of poisoning increases with the absorption of lead and lead compounds into the body. Biological monitoring of lead workers is a tool for assessing the uptake of lead and can indicate those who are at risk of lead poisoning. The Control of Lead at Work Regulations 2002 requires that medical surveillance should, include biological monitoring and be carried out on employees where exposure is ‘significant’.
Biological monitoring of lead workers can indicate those who are at risk of lead poisoning. The risk of poisoning increases with absorption of lead and lead compounds. However there can be marked variation between individuals.
The taking of these samples is a legal requirement.
Blood-lead levels are usually checked every 3 months, especially if a worker is below 18 or a woman capable of having children. The doctor may check the blood levels of workers less often if exposure and blood-lead level do not usually change very much. This could be every 6 or even 12 months.
Employees should have been provided with suitable and sufficient information on the health risks associated with lead, on the routes of lead exposure and on the measures to prevent or control exposure during the CRT recycling process.
Employees should also have had instruction and training on how and when to use the control measures (e.g. LEV systems including fault detection, RPE and how often to change the filters, PPE and the correct method of removing and refitting gloves), on the methods of work used (e.g. to handle the CRTs carefully at all times), and on the need for a high standard of personal hygiene and good housekeeping.
There should be a system for reviewing and updating the information, instruction and training for example by providing regular “toolbox” talks.
Exposure to lead is considered a “serious health risk” within the Enforcement Management Model (EMM) framework.
Any enforcement action taken should reflect the emphasis in Regulation 6 of CLAW 2002 (as well as Regulation 7 of COSHH 2002 (as amended) and Schedule 2A)) to ensure exposure is prevented or, where this is not reasonably practicable, adequately controlled.
Failures to achieve the expectations outlined below would result in a “substantial” risk gap in EMM and the initial enforcement expectation would be an Improvement Notice. Inspectors should also take into account duty holder and strategic factors before reaching a final decision on what action to take.
The lead assessment should be suitable and sufficient and include all the tasks where exposure to lead is possible including the frequency and duration of the tasks. The assessment should cover how exposure is controlled and the effectiveness of the control measures in place. If the assessment is not adequate consideration should be given to issuing an Improvement Notice (IN) (CLAW Regulation 5 and COSHH Regulation 6).
The company should have a procedure for reviewing and improving exposure controls if personal exposures to lead are high. If there is evidence that such reviews are not taking place consideration should be given to issuing an IN (CLAW Regulation 6 and COSHH Regulation 7).
An employer must take immediate steps to remedy the situation where the OEL for lead has been exceeded. The employer’s first step should be to consider if there is a visible obvious reasons for the results. If it is an isolated result, or one or two results which marginally exceed the OEL the employer should consider whether or not they have real significance and indicate a failure to maintain adequate control, or whether they reflect an error in the measurement method. Additional measurements may be required.
If the employer concludes that the air monitoring results do not indicate adequate control of exposure, the further steps to be taken include:
The employer should check that any remedial action to tighten control has been effective.
LEV, used to control the risk of exposure, should have been thoroughly examined and tested within the last 14 months. If no thorough examination and testing have taken place consideration should be given to issuing an IN (CLAW Regulation 8 and COSHH Regulation 9). If the LEV thorough examination and testing is of a poor quality then it should be followed up with the supplier.
The company should have arrangements for suitable air monitoring for lead. If suitable arrangements are not in place consideration should be given to issuing an IN (CLAW Regulation 9 and COSHH Regulation 10).
The company should have arrangements for suitable health surveillance for lead. If suitable arrangements are not in place consideration should be given to issuing an IN (CLAW Regulation 10 and COSHH Regulation11).
The company should provide adequate training, information and instruction for their employees in controlling the risks of exposure. If provision is deemed inadequate consideration should be given to issuing an IN (CLAW Regulation 11 and COSHH Regulation 12).
NB: Where inspectors come across situations where the control of exposure is clearly grossly inadequate (e.g. evidence of contamination by dust, none or inadequate LEV, none or inadequate PPE/RPE, lack of welfare facilities etc.) coupled with lack of exposure monitoring and/or health surveillance taking place consideration should be given to issuing a Prohibition Notice (PN) under Regulation 6 of CLAW 2002 and 7 of COSHH 2002 as amended (as well as Section 2 of Health and Safety at Work etc. Act 1974).
In cases of doubt the inspectors should consult their relevant local Specialist Inspectors for further advice.
