Subject to its own set of regulations, Lisa Bushby briefly discusses the risks associated with lead and its compounds, and describes some of the measures required to manage exposure.
Having long been known to have the potential to damage health, lead and its compounds are subject to the requirements of its own set of regulations in the UK, namely the Control of Lead at Work Regulations 2002 (CLAW).
Lead is a silver-grey metal with a melting point of 327°C and a boiling point of 1740°C. It is highly lustrous when freshly cut, but tarnishes when exposed to air. It is very soft and malleable and is easily melted, cast, rolled and extruded. It is widely used in batteries and solders, as an anti-knock additive for motor fuels and also in glasses and glazes in the ceramic industry and as a pigment in paints.
Risk to human health
Lead and its compounds can be absorbed into the body by inhalation of dust, aerosol, fume and vapour, with the degree of absorption dependent on particle size and solubility. Once absorbed, lead binds strongly to red blood cells, and is then deposited in bone, where it accumulates. The elimination half-life for lead in bone is likely to be in excess of 20 years. The first symptoms associated with exposure to lead include headaches, tiredness, irritability, constipation, nausea, stomach pains, anaemia or loss of weight. Continued uncontrolled exposure can lead to kidney damage, nerve and brain damage, and infertility. Young people are at greater risk than other employees, and as an unborn child is at particular risk from exposure to lead, especially in the early weeks before a pregnancy becomes known, CLAW requires additional measures to be taken for women of child-bearing age.
CLAW applies to any type of work activity that is liable to expose employees or any other person to lead in the form in which it is likely to be inhaled (eg lead dust, fume or vapour), ingested (eg lead powder, dust, paint or paste) or absorbed through the skin (eg lead alkyls or lead naphthenate).
Managing “significant” exposure
An employee’s exposure to lead is considered “significant” if one of the following three conditions is satisfied.
Exposure exceeds half the occupational exposure limit for lead.
There is a substantial risk of the employee ingesting lead.
There is a risk of an employee’s skin coming into contact with lead alkyls or any other substance containing lead in a form, such as lead naphthenate, which can also be absorbed through the skin.
If exposure is likely to be significant, employers must:
issue employees with protective clothing
monitor lead-in-air concentrations
place the employees under medical surveillance.
A high standard of personal hygiene plays a crucial role in controlling lead absorption. Suitable and sufficient washing facilities, including showers where appropriate, are an important requirement for those exposed to lead at work. Also, lead can be easily absorbed through ingestion. To avoid this risk, the CLAW impose duties on employers to make sure that employees do not eat, drink or smoke in any place that may be contaminated by lead.
Personal protective equipment (PPE)
Employers should use PPE where adequate control cannot be achieved solely by the application of operational or engineering measures appropriate to the activity and consistent with the risk assessment. PPE must be provided where the exposure of the employee to lead is liable to be significant, though there may also be other circumstances where it is also advisable to issue PPE such as clothing, masks and gloves to provide employees with additional protection should any of those measures fail. The use of suitable respiratory protective equipment should only be considered as a method of control after all other measures have been taken.
Inhalation is one of the main ways lead can enter the body. As such, employers that deal with significant quantities of lead should:
introduce control measures to ensure the amount of lead in air in the breathing zone of any employee does not exceed the appropriate occupational exposure limit (OEL)
carry out a regular programme of air monitoring to check that the control measures are working effectively and that the OEL is not exceeded.
The OEL for lead is given in CLAW as follows:
lead other than lead alkyls, a concentration of lead in the atmosphere to which any employee is exposed of 0.15 mg/m3
lead alkyls, a concentration of lead contained in lead alkyls in the atmosphere to which any employee is exposed of 0.10 mg/m3
There is not necessarily a strong relationship between the amount of lead the body absorbs and the concentration of lead-in-air. Consequently, employees whose exposure to lead is significant should be referred to a doctor as a matter of urgency to assess the severity of the case, and how much lead they will have absorbed.
Should an employee be found to have exceeded the OEL, employers must:
carry out an urgent investigation to find out why
review control measures
take steps to reduce the employee’s blood-lead concentration below the action level, so far as is reasonably practicable.
Last reviewed 8 May 2015