Dust and aerosols - welding fumes

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Klaus Kuhl (Kooperationsstelle Hamburg IFE GmbH), Mario Dobernowsky (Kooperationsstelle Hamburg IFE GmbH)


Introduction

Welding creates major problems for health and safety:
(i) fumes that may cause airway disease and contain carcinogenic substances,
(ii) working in confined places and/or in awkward positions. Different technology, substrates, fillers, and working conditions create many different scenarios.
This article addresses health issues, preventive measures including exhaust systems, low fume generating welding, training of movements that avoid breathing in of fumes, and helmets with integrated air supply. It also presents tools that can be used by SMEs, and an outlook indicating the most important trends in welding and the related health issues.


Welding and OSH

Health and safety can be affected by welding operations:
(i) welding generates fumes that may cause airway disease and contain carcinogenic substances, whereby some welding technology may create high amounts of fumes,
(ii) hot surfaces and ultraviolet rays,
(iii) many welders have to work in confined places and/or in awkward positions,
(iv) restrictions for movements and increased load because of the heavy protection welders have to wear or carry, and
(v) working on site may include working without shelter exposed to rain, which increases the risk of electic shock considerably.
These risks can be considerably reduced by automated processes. However, they are only applicable for welding long beads as in shipyards or they need a high investment, which makes it difficult for small companies. The different types of welding machines, substrates, fillers and the various types of working conditions create many different scenarios. This article addresses health issues linked to exposure to welding fumes, preventive measures including exhaust systems, low fume generating welding, training of movements that avoid breathing in of fumes, and helmets with integrated air supply. It also presents risk assessment and training tools that can be used by SMEs and an outlook indicating the most important trends in welding and the related health issues.

Welding is a generic term for joining pieces of metal at joint faces rendered plastic or liquid by heat or pressure or both [1]. These processes generate several health and safety risks for the welders and workers nearby, such as fire and explosion risks, burst of pressurised cylinders, heat and burns, electrical risks, risks from ultraviolet and other electromagnetic radiation, working in awkward positions, and fumes that may enter the breathing zone of the welders or their colleagues.

Exposure to hazardous substances related to welding

There are a variety of different types of welding processes[2] used in industry. The type of process used will impact on the nature and extent of dangerous substances produced in welding fumes. Thus the composition of welding fumes will depend on the substrate, the filler material, the possible use of separate electrodes as in TIG welding, gases used for heat generation, gases or materials used for focusing the arc, and shielding of the arc and the bead against oxygen, possible coatings of the substrate, possible dirt on the substrate and on the adjustment of the welding machine or torch.

Depending on these factors, welding fumes may contain a large variety of particles and gases that pose hazards as listed in the following table.

Table 1: Welding technology and generated hazardous substances

Welding technology Description of welding technology Particle emission rate (mg/s) Hazard class of particle emission Other exposures
Substances that place strain on respiratory tract and lungs Toxic or irritating substances Carcinogenic substances
Submerged arc
Usually an automated process
Flux shielded arc welding.

A blanket of granulated flux is deposited on the workpiece, followed by a consumable bare metal wire electrode. The arc melts the flux to produce a protective molten shield in the welding zone.

< 1 low low low Ozone, nitrogen dioxide
Gas welding (autogenous procedure)
Manual process
The torch connected to an oxygen and an acetylen cylinder melts the metal surface and filler rod, causing a joint to be formed on solidification. < 1 low low - Nitrogen dioxide, carbon monoxide
TIG, tungsten inert gas welding
Manual process but also used in automated, robot operated processes
Gas shielded arc welding.

The tungsten electrode is non-consumable, and filler metal is introduced as a consumable into the arc manually.

< 1 low medium medium Ozone, nitrogen dioxide, carbon monoxide
Laser welding without filler metal Laser beams can be used in industrial applications requiring exceptionally high precision, such as miniature assemblies and micro techniques in the electronics industry or spinnerets for the artificial fibre industry. The laser beam melts and joins the workpieces. 1 to 2 medium high high X rays at high voltages
MIG/MAG metal inert/active gas welding

(low energy, pulsed current machines)
Manual process but also used in automated, robot operated processes

Gas shielded arc welding.

The electrode is normally a bare consumable wire of similar composition to the weld metal and is fed continuously to the arc.

1 to 4 low medium medium to high Ozone (especially high in in MIG-welding of aluminium materials),
carbon monoxide with MAG welding with CO2 shield gas of unalloyed and low-alloy steel
Shielded metal arc welding (SMAC); “stick” arc welding; manual metal arc welding (MMA); open arc welding Flux shielded metal arc welding.

Uses a consumable electrode consisting of a metal core surrounded by a flux coating

2 to 8 high high high Nitrogen dioxide
MIG (general) Gas shielded arc welding. 2 to 8 high high high Ozone in MIG-welding of aluminium materials
MAG (solid wire),
Flux-cored wire welding with shield gas (MAG)
Gas shielded arc welding. 6 to 25 high high high Carbon monoxide with MAG welding and CO2 shield gas of unalloyed and low-alloy steel
MAG (flux-cored wire),
flux-cored wire welding without shield gas
Gas shielded arc welding.

Uses a flux-cored consumable electrode; may have carbon dioxide shield (MAG).

> 25 very high very high very high Carbon monoxide with MAG welding with CO2 shield gas of unalloyed and low-alloy steel
Autogenous flame cutting
Manual and automated process, also robot operated
The metal is heated by a flame, and a jet of pure oxygen is directed onto the point of cutting and moved along the line to be cut. > 25 very high very high very high Nitrous gases

Source: adapted from Platcow and Lyndon [1] and from TRGS 528 [3]

Annotations:
The Emission rate column presents empirical values which can be reduced in individual cases by optimising the process parameters. TIG welding: figures given according to exposure description published by the German accident insurance associations [4] Other hazardous substances that could be part of the welding fumes are generated from coatings or impurities, such as epoxides, isocyanates, aldehydes [3].

Prevention and control measures

A large survey in the Netherlands showed that the calculated chance at exceeding the (former) OEL for welding fume of 3,5 mg/m3 was 80% in a group of 53 welders [5]. Thus, for the current OEL of 1 mg/m3 this would have been even much higher – close to 100%. Major factors determining exposure were relative welding time (relative to total work time), the position of the head of the welder (e.g. bent over the rising fume) and whether or not they worked in confined spaces.

This underlines the need to establish effective prevention and control measures, that are based on a risk assessment and follow the the generally accepted hierarchy of control measures (see also: The hierarchy of control measures regarding dangerous substances).

Avoidance of risks and elimination of hazards – choosing a welding procedure

All welding processes involve certain risks for the welders, the colleagues nearby, or – in case of automated welding – for the machine operators and the maintenance workers. Elimination would therefore require choosing safer processes, such as joining by bolting pieces together. However, as this involves more time and resources, generally the application would be disproportionate in terms of effort and achievable results. The usual option is therefore to minimise the hazards and put means of separation between the source and the workers in place. The other possible alternative: using adhesives creates new risks, such as vapours and sensitising risks (see also: Substitution).

Also the selection of non-stainless steels would avoid the generation of carcinogenic fumes, however, this is not always possible as it may lead to increased corrosion and related maintenance and replacement problems.

The first option is to select a welding technology that would generate the least amount of hazardous substances. The table above (1) can be used as a guideline regarding particles generated by the welding process: Where possible the processes: submerged arc (automated welding), gas welding or TIG welding should be selected. If MIG/MAG welding is necessary, modern welding machines with pulsed current should be used, as these produce considerably less welding fumes as compared to the older types of machines. Another option, that is however, rarely applicable in small companies, could be the automatisation of the welding process, e.g by a robot.

Technical measures to minimise hazards and to separate hazards from bystanders

See also: Engineering controls (2nd level).

An optimum adjustment of the machines is necessary (consult the manual) as deviations will increase the amount of hazardous substances generated.

Before welding on coated or dirty material, the coating and dirt in the areas to be welded should be removed thoroughly. Paint coatings may contain nanomaterials (see last chapter “Outlook”).

In parallel to these efforts, the hazardous substances should be kept away from the welders and their near-by colleagues, who are not performing welding tasks, by separating work areas or using ventilation.

As an example of European preventive actions the German accident insurance associations have developed the following (table 2) binding rules, which have been intergrated into the mentioned governmental technical rule TRGS 528 [3]:

Table 2: Exhaust systems for welding procedures with filler material

Process Filler material and welding time (short- or long-term)
Mild steel and low-alloy steel, aluminium material High-alloy steel, non-ferrous metal (except aluminium material) Welding on coated steel
s l s l s l
Gas welding - stationary F T T L T L
Gas welding - mobile F T F L F L
Manual arc welding - stationary T L L L L L
Manual arc welding - mobile F T T L T L
MIG-, MAG-welding - stationary T L L L L L
MIG-, MAG-welding - mobile F T T L T L


TIG welding, thorium oxide free electrodes - stationary F T F T F T
TIG welding, thorium oxide free electrodes - mobile F F F T F T
TIG welding - stationary L L L L L L
TIG welding - mobile T L F T F T
Submerged arc welding - stationary F T T T T T
Submerged arc welding - mobile F F F T F T
Flux-core welding*
s = short-term welding (burning of flame or arc does not exceed half an hour per day or two hours per week)

l = long-term welding

F = free natural aeration

T = technical (machine) ventilation
L = local exhaust ventilation (LEV)

*The relatively new process: flux core welding without shield gas is not yet considered in the above table. It generates large amounts of fumes (see table 1) and therefore in any case local exhaust ventilation (LEV) should be used.

Source: adapted from BGR 500 [6]

Various types of LEV are on the market:

  • work benches with downdraft ventilation,
  • use of hoods; large hoods or small moveable hoods,
  • tip-extraction (on the welding equipment),
  • shield extraction,
  • new developments such as smart exhaust arms that follow the welding progress automatically [7].

The best solution in each given work situation has to be carefully established. It is strongly recommended that expert guidance is sought for the selection and installation of the ventilation [8].

Depending on the type of local exhaust ventilation in use, frequent re-adjustment may be necessary as the work progresses. An alternative could be provided by extraction integrated in the torch or mounted directly on the torch, or welder protection shields with integrated extraction. The effectivity of the extraction would be the better the nearer the nozzle is put to the source of the welding fume. However, at a certain point it would compromise the quality of the welding bead as it would take away some of the shiedlding gases. An ideal postion is to have it not farther away than one diameter of the nozzle. An HSE-report describes high capture efficiencies of more than 90% for on-tip extraction, but studies during actual working practice in Dutch companies only established a 50% efficiency. [9]

Exhausted air has to be replaced by fresh air. The extracted air at workplaces where welding work involves the emission of carcinogenic or mutagenic substances or substances toxic to reproduction of category 1 or 2 (especially with the use of chromium- and nickel-bearing materials) must not be fed back into the workshop (see also: Carcinogenic, mutagenic, reprotoxic (CMR) substances).

Maintenance of machinery and work spaces

The employer has to ensure that all machines and devices are in appropriate conditions and that they are serviced and checked regularly.

Workplaces have to be cleaned by a suitable and tested industrial vacuum cleaner.

All preventive and control measures have to be examined for their efficacy regularly. A good method for this is provided by the PIMEX system as it allows to comprehensively analyse the complete welding process including the extraction system and the PPE. At the same time it allows to improve the process until a minimisation of the exposure is achieved [10] . PIMEX is an acronym from the words PIcture Mix EXposure, and implies that the method is based on mixing pictures, in this case from a video camera, with data on a worker’s exposure to some agent.

Organisational measures to minimise hazards and to separate hazards from workers

See also: Organisational measures of accident prevention.

The number of workers and passers-by that could be exposed to substances generated by welding has to be kept to a minimum. This could be achieved by a related work organisation and / or by indicating or cordoning off of work areas.

However, there has to be sufficient surveillance for lone workers, especially in confined spaces.

Monitoring of exposure

The employers have to ascertain that the relevant OELs are observed. Usually, respirable dust can be used as a representative measurement category. In order to protect workers, many European countries have set occupational exposure limits for inhalable (10 mg/m3) and respirable dust (between 3 and 6 mg/m3) [11] as well as welding fumes (usually 5 mg/m3). However, it may be necessary to also measure metals in the welding fumes, such as chromium(VI) compounds and nickel and nickel compounds [12] [13]. Reference values indicating the state-of-the art can be found for example in the above-mentioned TRGS 528 [3]. For example several European countries have set an OEL of inhalable Cr VI aerosols at 0.05 mg/m3 [11].

Important indications may also be obtained from biomonitoring.

Health problems generated by welding and health monitoring

The generated substances can have the following effects in humans [3]:

  • The fumes generated by welding have diameters in the range of 8 to 0.01 µm and can enter the deeper parts (alveolae) of the lungs [12].
  • Metal fumes such as iron oxides and aluminium oxide place a strain on the respiratory tract and lungs, meaning that effects in the sense of a chronic inflammation (chronic bronchitis) may occur by an overload of particles [3].
  • Fumes containing fluorides, manganese oxide, copper oxide, have a toxic or toxic-irritating effect [3].
  • Fumes containing chromium(VI) compounds and nickel oxides are carcinogenic, may cause allergies and can occur when stainless steel is being welded [3]; see also: Carcinogenic, mutagenic, reprotoxic (CMR) substances.
  • Ozone in high concentrations is very toxic, it irritates the respiratory system and the eyes. Leads to tussive irritation, shortness of breath and possibly oedema of the lungs [12].
  • NOx can also cause oedema of the lungs [12] .
  • Carbon monoxide is a very toxic gas that can cause oxygen deficiency in tissues and asphyxiation. It is also a reproductive toxicant [12] .
  • If the welded parts have been coated by paints, plastic, or if they have been electroplated or galvanised, or if they are dirty, a wide variety of additional hazardous substances may be generated that cause additional problems in humans, such as formaldehyde (cancerogenous), isocyanates (sensitising) and additional metal oxides (e.g. zinc oxide causing metal fume fever) [12].

Epidemiological studies on welders have shown respiratory effects such as bronchitis, airway irritation, lung function changes, and a possible increase in the incidence of lung cancer [14]. In some few cases nasal septum perforation occurred in long time stainless steel welders [15]. A recent study among 6000 Danish welders pointed at an increased risk of cardiovascular disease [16] as well. Siderosis (welder’s lung) is an acknowledged occupational disease on the list of the European Union [17].

Medical surveillance of the workers may be needed, if there is:

  • an exposure to carcinogenic compounds, such as chromium VI, nickel, cadmium,
  • an exposure to fluorine and inorganic fluorine compounds,
  • an exposure to dust concentrations above the OEL,
  • need to wear breathing protection; a surveillance is needed because of the high strain from wearing PPE, carrying heavy equipment, working in uneasy postures and confined spaces and in high temperatures or outdoors.

Some hazardous substances which pass into the human organism through the inhalation of welding fumes can be determined in biological material (especially urine, full blood or blood serum or in the red blood cells). Thus biomonitoring could be included in the medical examinations [3].

Personal protective measures to minimise hazards

Where the described types of protective measures are not sufficient (e.g. OELs are not complied with), the employer must provide suitable respiratory protective equipment, which must be used by the workers. It is imperative to wear PPE when welding high-alloy steels, such as stainless steel, except when using low-emission procedures such as submerged arc or TIG welding.

The following are examples of respirators that may be used as personal protective measures:

  1. ventilated helmets / hoods with blower and particle filter TH2P or TH3P,
  2. masks with blower and particle filter TM1P, TM2P, TM3P,
  3. full-face masks or mouthpiece fittings with P2 or P3 filters,
  4. half-face / quarter-face masks with P2 or P3 filters, particle-filtering half-face masks FFP2 or FFP3 or
  5. insulation devices.

If gaseous hazardous substances arise during welding, combination filters must be used when wearing filtering respiratory protective equipment [3].

For welding jobs carried out in confined spaces, the following procedure for the selection of respiratory protective equipment can be used:

  1. If possible a feed air and exhaust air system must be installed in the working area.
  2. If this is not possible or not adequate for spatial reasons, preference must be given to the wearing of ventilated hoods or helmets.
  3. If it is not possible to use ventilated hoods and helmets for spatial reasons, FFP2 masks with exhalation valve at least must be worn when welding low-alloy steels, and FFP3 masks with exhalation valve when welding high-alloy steels.
  4. If it is to be expected that nitrous gases will be emitted, e.g. with flame straightening, suitable respiratory protective equipment must be used.
  5. If there is the risk of oxygen deficiency, respiratory protective equipment which is not dependent on the ambient air (insulation devices) must be used [3].

When removing nanomaterial containing paint coatings in preparation of welding jobs by dust producing work procedures, a particle filter P2 (white) or a particle filtering half-mask FFP2 should be worn [18].

Training and information

Welders have to receive proper instructions from their supervisors before starting to weld. All prevention and control measures should be clearly explained and practised sufficiently. The welders should be involved in risk assessment and the selection of appropriate measures at their work place. The PIMEX system (see section 2.3) is a good method to motivate the workers to identify shortcomings and take active part in improving the situation. The video recordings of workers performing welding tasks can be used during training sessions.

Measures to improve safe behaviour

The health risks of welding processes are frequently underrated by employers and workers. Therefore the application of protective measures is not as effective as it could be (see also: Hierarchy of prevention and control measures. Efforts to improve safe working practices need, however, certain preconditions such as example-setting by managers and supervisors, a no-blame culture, a timely feed-back to suggestions, proper induction and regular refresher training. Methods to achieve an improvement include peer observation and the use of the PIMEX system.

Tools for SMEs

In order to select the most appropriate and effective measures, the employer respectively the OSH professionals usually need to look into several (national) directives, rules and guidelines. Some member states provide detailed guidance and legislation for welding. SMEs certainly need some assistance here, and to that end several tools have been developed (see also: Risk management for dangerous substances) for example:

  1. The Britisch Health and Safety Executive (HSE) has provided an interactive website: It offers task specific COSHH guidance for welding, cutting and allied jobs [19] . In addition, HSE provides detailed advice structured according to different locations and different materials.
  2. A Dutch institute developed the "Welding Fume Assistant". This exposure assessment tool has been replaced by an updated instrument called “Verbetercheck Lasrook (Improvement Check Welding Fume)” – an online tool similar to GISMET described below. As means of illustration it contains PIMEX clips, and good practice descriptions [20].
  3. Kooperationsstelle Hamburg (KOOP) has developed the GISMET system for the German insurance associations for the metal sector (so far available in German only). The web-based interactive tool allows users to select specific scenarios, such as ‘MAG-welding high-alloy steel in confined spaces’ or ‘manual arc welding of mild steel more than 2 hours per day in the workshop’. In return the users find detailed and specific information for example [21]:
    • Health hazards and OELs
    • Suggestions for less hazardous processes
    • Technical measures (e.g. exhaust system to be used)
    • Organisational measures
    • Personal measures (e.g. which respirators, filters to be used)
    • How to check the effectiveness of the measures.

Outlook

Besides the pulsed current welding machines, which improve the quality of the welds and reduce the amount of fumes, the technological development has brought more “quick and dirty” welding machines on the market as well, such as flux cored wire welding without shield gas. These can be used very easily, because they need very little training and preparations, but may cause high exposures. Therefore it is all the more necessary that SMEs find equally easily accessible health and safety guidelines and assistance. Guidelines so far available in paper or pdf format may not be useful for SMEs and micro enterprises, because finding information for the various specific scenarios is difficult. Web based tools have an advantage as they allow an easy selection of scenarios and can provide the related specific measures: namely which welding processes are possible for the given job, which exhaust system and breathing protection has to be used. More efforts should be put in the devlopment of such tools and the improvement of existing ones.

Ultrafine particles – particles whose diameter is in the nanometer range – have come into the focus of researchers. There is evidence that welding processes generate a considerable amount of these particles, that they can enter the alveoles and can hardly be removed by the body. They may cause considerable health problems such as inflammatory, fibrogenic and carcinogenic effects [22] [23]. Nanotechnology has found its way also into paints, and paint coatings may contain nanomaterials. The German insurance association for the construction sector regards it as a low risks as these nanomaterials are fixed in a matrix. Nevertheless, they advise that when removing the paint mechanically (e.g. by grinding) to use machines with an integrated vacuum cleaner. When removing nanomaterial containing paint coatings in preparation of welding jobs by dust producing work procedures, appropriate PPE should also be worn additionally to the provided technical measures. Fortunately the preventive and control measures as presented in this article are suitable to minimise and control exposure to ultrafine particles [3].

References

  1. 1.0 1.1 Platcow, P., Lyndon, G. ‘Welding and thermal cutting’, Encyclopaedia of Occupational Health and Safety, ILO (Ed.), 2003. Available at: http://www.ilo.org/safework_bookshelf/english/.
  2. List of welding processes. Available at: https://en.wikipedia.org/wiki/List_of_welding_processes
  3. 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 Committee on Hazardous Substances (AGS), Technical Rules for Hazardous Substances TRGS 528 – Welding work, published by the German Federal Ministry of Labour and Social Affairs (BMAS) in the Joint Ministerial Gazette (GMBl), 2009. Available at: http://www.baua.de/en/Topics-from-A-to-Z/Hazardous-Substances/TRGS/TRGS-528.html.
  4. HVBG – Hauptverband der gewerblichen Berufsgenossenschaften, BG-Information BGI 790-12 – BG/BGIA-Empfehlungen für die Gefährdungsbeurteilung nach der Gefahrstoffverordnung Wolfram-Inertgas-Schweißen (WIG-Schweißen), Carl Heymanns Verlag, 2006. Available at: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCMQFjAA&url=http%3A%2F%2Fabekra.de%2FBerufskrankheiten%2FRisikobereiche_Risikostoffe%2520allgemein%2FMetall_Loesemittel%2Fbgi790_12%2520Schweissen%2520Gefaehrdungbeurteilung%2520Wolfram-Inertgas-S.pdf&ei=XHd2UKW_KcjXsgbmrICQDQ&usg=AFQjCNGsx3FBLNBori9ADD1_Vwvb8ToCYQ&cad=rja.
  5. Scheepers, P.T.J., Geertsen, E., Peer, P., Willems, J., Blootstelling aan lasrook en chroomverbindingen bij laswerkzaamheden in de metalektro en metaalbewerking - Twee onderzoeken (Exposure survey during welding work: welding fume and chromium compounds), UMC/ Radbouw/ Arbo Unie, the Netherlands, 2003. Available at: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCMQFjAA&url=http%3A%2F%2Fwww.veiligheidskunde.nl%2Fxu%2Fdocument%2Fcms%2Fstreambin.asp%3Frequestid%3DCC3D2A5D-D324-4182-895D-40AA89A416BE&ei=dGGiT7SBJ8_ltQaCoMWXBw&usg=AFQjCNFbEz6WBQoxrXmKJc-JTquks23D6Q.
  6. BGR 500, Betreiben von Arbeitsmitteln - Metallspezifischer Auszug, Kapitel 2.26, Schweißen, Schneiden und verwandte Verfahren, VMBG 2005. Available at: http://www.bgbau-medien.de/zh/bgr500/2_26_titel.htm.
  7. IIS – Istituto Italiano della Saldatura (Italian Institute of Welding), ECONWELD Economically welding in a healthy way - Collective Research, Horizontal Research Activities involving SMEs, Intermediate report on progress on reducing the emission at the source, 2006. Available at: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&sqi=2&ved=0CD4QFjAB&url=http%3A%2F%2Fwww.ewf.be%2Feconweld%2FgetDoc.aspx%3FidDocumento%3D256&ei=iWCaT931L4TdsgbM_IzqDg&usg=AFQjCNEHjEMNSnp94_eILhynNZNWRAdPWw.
  8. HSE - Health and Safety Executive, Controlling airborne contaminants at work; A guide to local exhaust ventilation, 2nd edition, 2011. Available at: http://www.hse.gov.uk/pubns/priced/hsg258.pdf.
  9. Pocock, D., Saunders, C.J., Effective control of gas shielded arc welding fume, HSE, UK, 2009.
  10. Rosén G. Andersson, I-M., Walsh, P., Clark, R., Säämänen, A., Heinonen, K., Riipinen, H., Pääkkönen, R. ‘A Review of Video Exposure Monitoring as an Occupational Hygiene Tool’, Ann. occup. Hyg., Vol. 49, No. 3, pp. 201–217, 2005, Published by Oxford University Press. Available at: http://www.du.se/PageFiles/8813/Artikel_PIMEXAnnals.pdf.
  11. 11.0 11.1 GESTIS – Gefahrstoffdatenbanken (Databases on hazardous substances), International limit values for chemical agents - Occupational exposure limits (OELs) (no publishing date). Retrieved 25 April 2012, from: http://www.dguv.de/ifa/en/gestis/limit_values/index.jsp.
  12. 12.0 12.1 12.2 12.3 12.4 12.5 Spiegel-Ciobanu, V., BG Information 593 – Hazardous substances in welding and allied processes, Ed. Vereinigung der Metall-Berufsgenossenschaften, Heymanns Verlag GmbH, Köln, 2007. Available at: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CDcQFjAB&url=http%3A%2F%2Fwww.heymanns.com%2Fservlet%2FPB%2Fshow%2F1226071%2Fbgi593e.pdf&ei=d5iCT5SlNs_XsgaN5aHMBA&usg=AFQjCNF9OB0RHZRHzcV2KT4BcUfjbvnJYA.
  13. Spiegel-Ciobanu, V., BG Information BGI 616 Beurteilung der Gefährdung durch Schweißrauche, Ed. Vereinigung der Metall-Berufsgenossenschaften, Heymanns Verlag GmbH, Köln, 2007. Available at: http://www.heymanns.com/servlet/PB/show/1224780/bgi616.pdf.
  14. Antonini, J.M., ‘Health effects of welding’, Crit. Reviews in Toxicology, vol. 33, pp. 61-103, 2003.
  15. Lee, C.R., Yoo, C.I., Lee, J.H., Kang, S.K., ‘Nasal Septum Perforation of Welders’, Journal of Industrial Health, Volume 40, Number 3, pp. 286-289.
  16. Ibfelt, E. Bonde, J.P., Hansen, J., ‘Exposure to metal welding fumes particles and risk for cardiovascular disease in Denmark: a prospective cohort study’, Occup. Environ. Med., 2010, Vol. 67, pp. 772-777.
  17. Commission Recommendation of 19 September 2003 concerning the European schedule of occupational diseases (Text with EEA relevance) (notified under document number C(2003) 3297), Official Journal, L 238, 25/09/2003 pp. 0028 – 0034. Available at: http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32003H0670:EN:HTML.
  18. BG BAU – Berufsgenossenschaft der Bauwirtschaft, WINGIS-online, Allgemeine Information für Tätigkeiten mit Nanoprodukten (Generic information on activities involving nano products); 9 April 2012. Retrieved 4 April 2012, from: http://www.wingis-online.de/wingisonline/default.aspx?PROGRUNR=800076-00&TYP=INFO&DETAIL=1100.
  19. HSE - Health and Safety Executive, Task specific COSHH guidance for welding, cutting and allied jobs(no publishing date). Retrieved 5 January 2012, from: http://www.hse.gov.uk/welding/guidance/index.htm.
  20. Koninklijke Metaalunie, Vereniging FME-CWM, FNV Bondgenoten, CNV Vakmensen en de Unie, 5x Beter, Werken is gezond (no publishing date). Retrieved 5 April 2012, from: http://www.5xbeter.nl.
  21. BGHM – Berufsgenossenschaft Holz und Metall, GISMET - berufsgenossenschaftliches Gefahrstoff-Informationssystem für die Metallbranche (no publishing date). Retrieved 5 April 2012, from: http://www.gismet-online.de. (Not yet publicly accessible, planned to go public in summer 2012.)
  22. Spiegel-Ciobanu, V., BG Information BGI 616 Beurteilung der Gefährdung durch Schweißrauche, Ed. Vereinigung der Metall-Berufsgenossenschaften, Heymanns Verlag GmbH, Köln, 2007. Available at: http://www.heymanns.com/servlet/PB/show/1224780/bgi616.pdf.
  23. IIW – International Institute of Welding, International Seminar: ‘Exposure to ultrafine particles in welding fumes’, Tagungsband (Seminar reader), ed. BG Metall Nord-Süd, Hannover, 2009. Available at: http://www.bghm.de/arbeitsschuetzer/fachinformationen/schweissen-und-verwandte-verfahren/schadstoffe-in-der-schweisstechnik.html.


Links for further reading

EU OSHA – European Agency for Safety and Health at Work, Dangerous substances (no publishing date). Retrieved 19 March 2012, from: http://osha.europa.eu/en/topics/ds.

EU OSHA – European Agency for Safety and Health at Work, Practical solutions (no publishing date). Retrieved 19 March 2012, from: http://osha.europa.eu/en/practical-solutions.

EU OSHA – European Agency for Safety and Health at Work, Case studies – search string “welding” (no publishing date). Retrieved 19 October 2012, from: http://osha.europa.eu/en/practical-solutions/case-studies/index_html/practical-solution?SearchableText=welding&is_search_expanded=&getRemoteLanguage=en&keywords%3Alist=&nace2=&multilingual_thesaurus2=&submit=Search.

Blunt, J., Balchin, N., Health and Safety in Welding and Allied Processes, Cambridge, Woodhead, 2002.

HSE - Health and Safety Executive, Scottish Centre for Healthy Working Lives, Respiratory Protective Equipment (RPE) Selector Tool (1 March 2012). Retrieved 12 April 2012, from: http://www.healthyworkinglives.com/advice/minimising-workplace-risks/respiratory-protective-equipment/rpe.aspx.