Case Study: Mitigating Health Risks in Large-Scale Steel Fabrication: Welding Fume Exposure Assessment

In this case study, we delve into the challenges and complexities of controlling occupational exposure to welding fumes in a large-scale steel fabrication company. This organization, primarily involved in the welding of mild steel, faces inherent difficulties in managing exposure due to the extensive movement required and the expansive areas their operations cover. An integral part of their daily operations includes exposure to various metallic components of welding fumes - a universal risk associated with large-scale welding. By examining the unique characteristics and requirements of this workplace, we provide insights into how these occupational hazards can be effectively managed while maintaining operational efficiency.
 

Our Methodology

To carry out this comprehensive occupational exposure assessment, we employed widely accepted methods stipulated in the Health and Safety Executive's guidance document MDHS 14/4, and the British Standard BS EN ISO 10882-1:2011. These methods allowed for the accurate measurement of personal exposure to metallic components of welding fumes, including manganese, chromium, and nickel.
 
The Workplace Exposure Limits (WELs) for these metals were carefully adhered to: manganese (0.5mg/m3 for inhalable dust and 0.2mg/m3 for respirable dust), chromium (0.05mg/m3), and nickel (0.5mg/m3 for inhalable dust and 0.1mg/m3 for respirable dust). These limits serve as benchmarks to safeguard workers from harmful exposure levels that could lead to adverse health effects.
 
Prolonged exposure to manganese fumes can lead to neurological conditions similar to Parkinson's disease, characterized by symptoms such as tremors and difficulty walking. Exposure to chromium, specifically hexavalent chromium, is linked to lung cancer and respiratory illnesses, while skin contact can result in dermatitis. Nickel, a known carcinogen and respiratory sensitiser, can result in lung and nasal cancer upon inhalation, and allergic reactions upon skin contact. Our assessment method aimed to determine the extent of these risks, and suggest measures to mitigate them, ensuring the continued health and safety of the company's workforce.

Observation

Our visit to a large-scale workshop in the construction sector involved assessing the exposure of three different groups to metal dusts and welding fumes: Welding Operatives, Fabrication Operatives, and Workshop Management and Office Employees. The Welding Operatives, numbering around 19, were engaged in MIG and Arc welding tasks for most of their shifts. With natural ventilation and without localized exhaust ventilation (LEV) systems, their exposure to harmful dusts was noticeable, despite the use of 3M Versoflo respirators and protective gear.
 
Fabrication Operatives, approximately five in number, were exposed to similar environmental conditions. They carried out various metalwork tasks, including cutting, grinding, and drilling. While they were not directly involved in welding, their proximity to such tasks increased their exposure to harmful substances. Their use of respiratory protective equipment (RPE), specifically JSP disposable dust masks rated FFP3, was inconsistent.

Workshop Management and Office Employees were also considered, given concerns about potential exposure to dusts from processes carried out in the vicinity of their workspace.
The company follows a strict 'clean as you go' policy for maintaining general cleanliness. Cleaning teams, present twice a week, handle waste removal and general cleaning activities. Employees clean down work areas, machinery, and equipment at the end of each shift or when different materials are worked on. Regular health surveillance, including lung capacity checks, dermal checks, and audiometry checks, are carried out annually. Employees also receive regular training on handling potentially hazardous substances and are made aware of the importance of adhering to Personal Protective Equipment (PPE) usage rules.

Despite these measures, the existing protective measures, particularly ventilation and LEV systems, may not fully mitigate the risk of dust exposure due to the scale and complexity of tasks involved. As a result, additional measures might be necessary to enhance safety. 
 

Air monitoring results

 
Air monitoring results indicate employees may be exposed to inhalable dust, iron fume, and inhalable and respirable manganese at levels above workplace exposure limits (WELs). Although exposures to respirable dust, copper, chromium, and nickel don't exceed WELs, their presence is significant. Notably, fabrication operatives are likely more exposed than welding operatives who wear air-fed hoods. The exposure to all assessed substances, except nickel, is deemed significant as it exceeds 50% of the WEL. Therefore, implementation of recommended actions is crucial.
We strongly recommend reducing personal exposure to these substances to levels As Low As Reasonably Practicable (ALARP), ideally below 50% of their respective WELs. After improving control measures, subsequent monitoring must be conducted to verify effectiveness.

Given nickel's carcinogenic and sensitizing properties, its exposure is considered significant even when exceeding only 10% of the WEL. It's recommended that personal exposure to nickel be maintained below 10% of the WEL, further emphasizing the importance of implementing the suggested actions.

Value Delivered

Our comprehensive evaluation of the construction workshop delivered significant value in identifying, understanding, and mitigating the risks related to dust and fume exposure.
Firstly, we recommended immediate and comprehensive training for all welding operatives on the use of local exhaust ventilation (LEV) systems, including their correct usage and limitations. This also encompassed understanding and adhering to the control measures provided. We proposed the consideration of pneumonia vaccination for employees until exposure can be reduced by other means.

Additionally, we suggested the adoption of a combination of portable LEV and on-torch extraction for MIG welding on large workpieces, to reduce personal exposure to welding fumes. We also advised the implementation of mechanical general ventilation across the workshop to disperse airborne contaminants, with a suggested time frame of 3-6 months.

In terms of respiratory protective equipment (RPE), we advised continuing the mandatory usage of air-fed hoods for welding activities, until more robust controls are established.

Turning to dust exposure, we recommended the immediate use of FFP3-rated RPE when working in the area. We again stressed the importance of instructing and training operatives about the purpose, correct use, and limitations of the control measures provided.

For metalwork activities, we suggested using a combination of portable LEV and on-tool extraction to minimize dust exposure. We also recommended the use of either disposable or half-face masks fitted with particle filters of an FFP3 standard for metalwork fabrication as a precautionary measure or until more robust controls are established.

The value we delivered is significant - our recommendations will not only protect employees' health and improve safety measures but also enhance productivity and minimize long-term liability for the company.