Occupational Hygiene: Lead Testing as a Cornerstone of Workplace Safety

Lead Exposure in the Workplace

Lead is currently, and has historically been, used in a wide variety of applications due to its abundance and low melting point which makes it an easy metal to work with. The primary way lead poses a danger to workers is through exposure via inhalation of lead dust.

In Australia, lead exposure in the workplace is a significant concern due to the health risks associated with both acute and chronic exposure. Lead can be found in various industries and applications, making it crucial for employers to implement stringent safety measures to protect their workers.

Some common applications and industries where workers may be exposed to lead include:

• Lead paint removal – Until relatively recently, many types of paint contained a high concentration of lead. Even though lead paint is no longer used extensively, as old lead paint degrades it can become hazardous.
• Manufacturing/working with products containing lead – Many products such as lead-acid batteries and old plumbing fixtures contain lead. Additionally, working with lead by cutting or handling compounds that contain lead can create lead dust which poses an inhalation risk.
• Lead metal work – Working with, and creation of, lead alloys is accompanied by a degree of lead exposure (subject to controls). Lead alloys such as leaded copper are used in items like mechanical bearings.

Fortunately, lead can be detected and monitored in a range of ways allowing exposure to be mitigated through the implementation of appropriate control measures for the specific application.

Health Risks Associated with Lead Exposure

Exposure to lead poses a health risk in one of two ways; a high level of exposure in a short period of time (acute) or through low-level exposure over a long period of time (chronic). Symptoms of acute lead poisoning include but are not limited to fatigue and muscle weakness, nausea and vomiting, as well as seizures. Onset time of acute symptoms depends on the degree of exposure. Long-term symptoms may develop slowly over a longer period of time and may include cardiovascular conditions like high blood pressure, neurological symptoms such as poor-coordination and memory loss and can even impact fertility in both males and females.

Health monitoring for workers who start or do lead risk work is required by the model Workplace Health and Safety Regulations which can help identify symptoms early, particularly in the case of chronic exposure. Safe Work Australia provides a guide to help persons conducting a business or undertaking (PCBUs) meet their health monitoring obligations.

The Role and Importance of Lead Testing in the Workplace

PCBUs have an obligation under the model Work Health and Safety Laws to manage the risks associated with using, handling, generating and storing hazardous chemicals (including lead) in the workplace. This also involves identifying ‘lead risk work’ and ensuring workers are not exposed to dangerous levels of lead.

‘Lead risk work’ is defined as the work carried out in a lead process that is likely to cause the blood lead level of a worker carrying out the work to exceed:

1. for a female of reproductive capacity — 5 μg/dL (0.24 μmol/L), or
2. in any other case — 20 μg/dL (0.97 μmol/L)

‘Lead process’ means work that exposes workers to lead particulates, dust or fumes, molten alloys containing lead, lead batteries or parts of lead batteries and lead based spray paint.

In order to mitigate lead exposure, it is fundamental to identify sources of lead exposure. Identification and monitoring of lead can be conducted in a variety of ways.

Surface Sampling for Lead Detection

Where a surface is suspected to be contaminated by lead or coated with lead paint, single-use swabs are generally used as they provide a simple, accurate and rapid method of determining whether lead is present. The specific method depends on the swab used but generally the swabs are rubbed against the surface and if lead is present, will undergo a colourimetric reaction. Whilst swabs such as the Dexsil Instant Lead Test Kit eliminate the need for laboratory analysis in many circumstances, where quantitative results are required such as concentration or type of lead compound, surface samples must be taken and analysed off-site which can be expensive and time consuming.

Dexsil Instant Lead Test Kit

Straight-forward, instant colourimetric test for lead contamination on non-porous surfaces including paint.

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Monitoring Lead Dust in the Atmosphere

Lead dust can also be present in the atmosphere. Safe Work Australia’s workplace exposure standards for airborne contaminants (WES) imposes a time weighted average (TWA) limit of 0.05 mg/m³ for inorganic lead dusts and fumes. PCBUs have a responsibility to ensure that workers are not exposed to levels above this limit. Predominately for compliance purposes, air sampling is used to determine what lead compounds workers are exposed to and at what concentrations they are exposed.

A standard air sampling set-up using a sampling pump and the relevant filter or cassette is used to collect lead dust at a known flow throughout the day as they conduct their ordinary activities. The sample is then sent to a lab for gravimetric analysis where the type of substance and time weighted average concentration can be determined. This information can then be used to determine what control measures need to be put in place to mitigate lead exposure.