The various industrial welding and thermal cutting processes produce fumes and cause serious hazards to workers undertaking the job.
A huge cohort of workers is potentially regularly exposed to welding fume, contributing significantly to the work-related burden of disease and injury (IARC, 2018). Welders are potentially exposed to metal fumes, gases, ultraviolet radiation, noise, electric shock, burns, and other hazards.
This article will discuss welding and thermal cutting fume, the health hazards caused, how to measure them, associated legislation and methods for their control.
Before we get into the details of welding and thermal cutting fume, let’s define the industrial process of welding and its types.
Welding and its types
Welding joins metals through coalescence, high heat or pressure, or both.
Some of the standard welding processes include Manual metal arc welding (MMA or MMAW); Tungsten-inert gas (TIG) or gas tungsten arc welding (GTAW); Gas metal arc welding (GMAW); Friction welding; Plasma arc welding (PAW); Flux-cored arc welding (FCAW), Brazing and’ silver’ soldering and Spot (resistance) welding, etc.
Plasma and oxy-fuel are the two most common thermal cutting processes.
Welding and Thermal Cutting Fume
Small particles produced by welding and thermal cutting are pretty tiny. They often have a diameter of less than 1um (in most cases, 0.1um; they are known as ultrafine particles). These particles are respirable and are referred to as “welding fume.”
While all welding and thermal cutting procedures produce smoke, the plume may be invisible to the welder or, in the case of some operations, to the viewer (Weld Australia, 2021).
The content of the fused chemicals and how they are carried out can influence the kinds and composition of airborne volatiles. The consumable electrode is the primary source of welding fumes.
Particulates are only created in the area of the heat source and are mostly contained inside the plume of hot gases rising from the weld zone.
Welding and thermal cutting operations produce a range of dangerous by-products.
Toxicity of Fumes Generated
The toxicity of Welding and thermal cutting fume depends on the quantity and type of material used. Based on the fume size and the components, the particulates might be taken into the bloodstream through the upper respiratory tract or moved to the lower gas-exchange areas of the lungs.
Many welding techniques generate a breathing zone concentration higher than the current exposure standard in non-ventilated laboratory tests. However, if workers work in a complete shift where welding and thermal cutting processes occur occasionally, the exposure might be less than the exposure standard limit.
Measuring Welding and Thermal Cutting fume
Fume measurement involves the use of occupational hygiene methods to sample the air in the welder’s breathing zone over the shift, followed by laboratory examination of the fume particles collected. The Australian Standard 3853.1 (2006), titled ‘Health and safety in welding and allied processes – Sampling of airborne particles and gases in the operator’s breathing zone – Sampling of airborne particles,’ describes how to determine personal exposure to welding fume and other airborne contaminants generated by welding-related operations.
While the particle size range might be smaller than 1um, AS 3640 mandates the collection of the inhalable percentage of the aerosol when sampling airborne fumes produced by welding or thermal cutting activities (2009).
Personal exposures in the workplace should be compared to an 8-hour Time-weighted average – Workplace exposure standard (TWA-WES), as supplied by Safe Work Australia (SWA), to determine the potential for adverse health effects from welding fume Not other classified (NOC) and its numerous components.
Furthermore, the investigation must consider other factors that can affect exposure on the day, such as the production rate, which determines the amount of welding work, the location of the task (e.g., in a designated bay, building, or outside environments), the presence of any ventilation (e.g., local extraction ventilation), and other ambient particulate exposures or dusty tasks performed adjacent to the worker.
An experienced Occupational Hygienist should perform air monitoring to check that the control mechanisms in place are effective or give information and solutions to assess health risks
Safe Work Australia’s (SWA) 2020a report states, “Given the significant composition variability in welding fumes, a gravimetrically determined Workplace exposure standard (WES) that can adequately protect workers cannot be determined.”
Health Risks caused by Welding and Thermal Cutting Fume Exposure
The various health risks caused by welding and thermal cutting fume exposure are explained in brief below:
Excessive or unchecked exposure to welding fumes increases the chances of lung cancer among workers, irrespective of the type of steel that was welded, and the process employed. It has nothing to do with the tobacco smoking or asbestos exposure history of a worker. The worst part is that exposure time limits or occupational hygiene practices cannot prevent the exposed workers from getting lung cancer, which becomes more prominent with years of welding.
As per a study (Honaryar et al., 2019), welders had a meta-relative risk of lung cancer of between 1.17 and 1.87 compared with those who have never welded or been exposed to welding fume.
Inflammation and Obstructive Pulmonary Disease
Welders were observed to have acute systemic inflammation after being exposed to welding fumes (median PM2.5 concentration of 1.66 mg/m3). Chronic welding fume exposure is linked to a reduction in lung function. Welders are more likely to develop the chronic obstructive pulmonary disease.
International Agency for Research on Alcohol, Drugs, and Cosmetology states that welding gases may raise the risk of cardiovascular disease in welders (IARC). Cardiovascular illnesses such as myocardial ischemia, cardiac arrhythmias, and atherosclerosis have been described in the research.
Increase in Blood Pressure
As per the findings of Taj et al. (2021), low-to-moderate welding fume exposure was linked to an increase in blood pressure.
Other Health Effects
As per (SWA, 2020a & b), welding fumes can cause upper respiratory tract irritation (nose and throat), chest tightness, asphyxiation, asthma, metal fume fever, lung damage, bronchitis, cancer, pneumonia, and emphysema.
Potential for Exposure
The type and seriousness of the potential risks resulting from exposure to welding and thermal cutting fume will depend on various factors mentioned in SWA, 2020b, which are as follows:
- Welding processes used, including electrodes.
- Characteristics of the materials welded.
- Surface coating of the materials should be checked for harmful ingredients like lead.
- Welding equipment’s condition.
- Workplace situations under which welding is carried out (e.g., working in confined spaces), and
- Experience and skills of the welder.
Australian organisations can significantly control exposure to welding and thermal cutting fume by utilising the hierarchy of controls in the sequence of their effectiveness as given below:
- Using pre-cast components to eradicate the necessity of welding or cutting.
- Use a safer (lower fume) alternative procedure or consumables.
- Efficient process containment and ventilation (e.g., use of local exhaust ventilation) or fume capture employing on-tool extraction (where possible) to capture the fume near the site of creation.
- Forced ventilation (e.g., using pedestal fans) may be used if the fumes are not aimed at other employees. Workers may also benefit from some thermal comfort provided by fans.
- Evaluation of discharge locations that do not pose a risk to neighbouring work parties who may not be using controls used by the welder themselves;
- Timely training on the health effects of welding and how welders can protect themselves; and
- Assessing the necessity to implement health monitoring.
- Easy access to and proper use of personal respiratory protection equipment (e.g., PAPR equipped with P2 filters, fit-tested negative pressure respiratory protection), as specified in AS/NZS 1715. (2009)
- Administrative controls, such as inspection and maintenance of controls to ensure they are fit for purpose, as well as limited access to areas where welding or thermal procedures are carried out; and
- Choosing a suitable location for storing and cleaning personal protective equipment.
Fundamental Control methods
Below given are some of the fundamental control methods for businesses in Australia to practice at their workplaces:
- It is recommended not to use a welder in the fume-releasing area whenever possible and replace them with automated welding processes.
- As per Weld Australia’s Fume minimisation guidelines, the work equipment should be arranged such that the welder’s head does not enter the plume.
- Employers should not anticipate the presence of a light cross-draught near the welder’s face to remove smoke from the welder’s breathing zone reliably. While mechanically aided ventilation (e.g., a fan) can be deployed, cross draughts adequate to disperse smoke may cause weld quality difficulties. Fume extractors (fixed, downdraft, or portable) and other fume control equipment may be necessary.
- Use protective equipment like respirators (e.g., P2) and air-fed helmets in instances where automated processes are not applicable.
- It is advisable to use a combination of fume control methods.
The current Australian WES for welding fume (NOS as an inhalable fraction) is a TWA value of 5 mg/m3.
Anitech considers that welding and thermal cutting fume exposures should be maintained as low as practically possible and that a TWA-WES for welding and thermal cutting fume Not Otherwise Specified / Classified (NOS / NOC) would be beneficial as a guiding value to activate relevant controls.
Additionally, we suggest the use of 1 mg/m3 (as an inhalable fraction) and a risk assessment process identifies the hazardous substances in the welding fume while considering all the available information on the type of material, its WES, size, and density of the fumes generated, etc.
Furthermore, sample filters with fumes should be monitored in the exposed area to note elements found and their WES value.
The above process should apply to the fumes from smelting and thermal cutting procedures.
Besides, we suggest NATA laboratory test welding fumes and get their results reported on NATA-endorsed test certificates evaluated by experienced Occupational Hygienists.
A good Occupational Hygienist can help you implement effective controls tailored to keep exposure limits in check and monitor worker health.
How can Anitech help?
Anitech’s expert Occupational Hygiene Consultants can help you perform risk assessment, develop monitoring strategies, perform monitoring and provide advice to reduce exposure for your workplace and safeguard the health of your employees.
Feel free to enquire about our Occupational Hygiene Monitoring Services on our web page here
If you wish Anitech’s expert Occupational Hygienists to guide you implement effective practices for your work sites and secure the health of your employees, do contact us!
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