DAVID LUCAS
E.9.1 Work in a ship yard
Introduction
Humans have long used ships as a means of transport for goods or people, for discovery or invasion purposes. Consequently, ship construction and repair have been industrial activities for many years. Within this sector, there are many different occupations, such as engineers, boilermakers, welders, pipefitters and ship painters, and each type of worker is exposed to multiple risks, mainly physical and chemical.
Historically, the major centres for construction and repair were linked with military activity, and developed in Europe, later in North America, and later still in Southeast Asia and India. In 1998, the proportion of worldwide naval construction and repair taking place in South Korea, Japan and China rose above 80% and many of the largest shipbuilding companies are from these countries. In Western Europe, the sector has one or two large companies per country, and a multitude of small and medium-sized companies. In 1999, 182 firms in the EU had fewer than 1,000 employees, 17 had between 1,000 and 2,000 employees, and the 28 largest shipyards had a total of 64,000 workers[1]. In 2020, there are about 150 large shipyards in Europe. Around 40 of them are active in the global market for large seagoing commercial vessels. Some 120,000 people are employed by shipyards (civil and naval, new building, and repair yards) in the EU.
With a market share of around 6% in terms of tonnage and 35% for marine equipment, Europe is a major player in the global shipbuilding industry2
Shipbuilding and ship repair both have high rates of occupational accidents, more so than building and public works, but generally, accidents are less serious in shipbuilding. Naval construction, and particularly naval repair, has high rates of occupational accidents. Historical data from the UK show 8,939 recorded accidents and an incidence of 7,010 accidents per 100,000 in 1974, with 19 fatal accidents in 1973 and 1975[2].
In a later study looking at 48 accidents involving ship repair workers, the most frequent part of the body affected by the accidents were hands, lower limbs and eyes, with the more serious accidents involving mainly hands and upper limbs. Most accidents, 62.5%, occurred on board, and the rest in the workshop3. This is likely due to the ergonomic and organisational constraints, short deadlines, on board ships that are being repaired.
Physical risks
Noise exposure
Noise exposure is one of the major occupational risks to which workers are exposed, particularly those involved in repair. The source of noise may be
- machines used as tools for cutting wood,120 dB peak noise[3],
- machine tools,
- impact, for example, hammering, cutting and falling sheet metal
- grinding and associated activities, for example, engine room machinery, welding, and grinding in resonant spaces
In studies of workers in a shipyard, peak noise exposure was recorded as
- 135 dB from falling sheet metal,
- 111 dB for grinding,
- 117 dB for planing and hammering
Exposure averaged over 8 hours was 93 dBA for a boilermaker and 94 dBA for a pipefitter.
For this particular group of workers there is one additional, aggravating factor. Many such workers are exposed to aromatic solvents such as toluene, xylene and styrene. These have been shown in the industry to be ototoxic and can, via cell toxicity, increase noise-linked hearing loss[4]. A study by Triebig involving 248 shipyard workers exposed to styrene showed that chronic intense exposure above regulatory limits (> 50 ppm) led to an increased risk of hearing loss[5]. Further information about noise can be found in Ch xxx
Musculoskeletal problems
Musculoskeletal problems, either acute or chronic, are frequent causes of time off work and declared occupational diseases in this population group.
Upper limb injuries
Use of vibrating tools such as grinders, scurfers and turners expose workers to the risk of harm to the hands and upper limbs. In a study of 114 construction workers using tools vibrating at 6.32 and 13.39 m/s2 respectively, a mean use of 4.64 hours per day was investigated, and the period to onset of Raynaud’s disease was half as long as that given in the ISO 5349 PARK standard[6]. This severe impact on the hands was confirmed by findings of reduced nerve conduction velocity in the wrist, hands and fingers in a population of workers in an American shipyard[7] and by the positive correlation between rates of vascular symptoms in the hand and the intensity of exposure to vibration via tools in 214 subjects[8]. Tendinopathies in the shoulders, 18% of welders in one shipyard[9], and elbows are also linked to such exposure. Further information on the effects of vibration can be found in Ch xxx.
Handling and staying in cramped positions for long periods are common in some types of welding and sheet metal jobs. A full welding kit can weigh over 30 kilos, and the nozzle can weigh 2.5 kilos. Electromyography tests on welders show heavy strain on the trapezium, deltoid and finger flexor muscles[10].
Lower back injuries
Effects on the lumbar muscles have also been observed. Axelopoulo studied 853 workers in a shipyard[11] and confirmed the increased incidence of lower back pain in welders working in shipyards. Over one year, 14% of workers took time off work because of lower back pain, and welders had the highest rate of absence at 18.3%. The recurrence rate reached 41% over the year, and was greater for those who had spinal disc herniation but reduced when working conditions were changed in favour of workshop work or limiting handling. This confirmed the considerable ergonomic constraints to which workers are subjected, particularly welders, pipefitters and sheet metal workers.
For engineers, the most risky aspect of work is handling, with equipment weighing tens or over a hundred kilos (stern post) that must be manipulated within confined spaces and with little leverage assistance, apart from hoists.
Eye injuries
The risk of ophthalmological disease is also high as reported by Brigham in 1985[12]. There are 2 main categories, foreign bodies in the eye and diseases related to ultraviolet (UV) and ionising radiation (IR) exposure. Grinding work is primarily responsible for exposure to the risk of foreign bodies in the eye. Acute corneal lesions, keratitis and secondary effects in the form of traumatic cataracts and ocular siderosis can all arise due to foreign body exposure[13]. Such accidents represented 27% of all occupational accidents in ship repair in 2007, and 18.8% in 2008[14]. Welding is the main activity that causes UV exposure, with the subsequent risk of ocular melanoma[15] and keratoconjunctivitis photoelectrica, known as “arc eye” [16].
Chemical risks
Asbestos
Asbestos was used in various forms in ships, in particular chrysotile, white asbestos, which is present in insulation and in Klinger jointing sheets (cross reference to chemicals chapter). Fibres from this known carcinogen are also present in flooring in engine rooms and living quarters[17]. It causes specific respiratory diseases that can be benign conditions of the parietal pleura, such as pleural plaques, benign pleurisy or fibrosis, or a form of pulmonary fibrosis called asbestosis. However, it can also cause malignant conditions such as primary malignant mesothelioma, cancers of the bronchi and lungs and, less specifically, cancers of the digestive, urinary or genital regions, including the kidney and ovary[18][19]. Workers employed in shipyards before 1980 suffered heavy exposure to asbestos with cutting and removal of insulation being the activities that involved the most exposure. In a study of 18,211 North American metalworkers, shipyard work represented a 1.85-fold increased risk of asbestos-related disease[20]. A long term study, between 1966 and 1975, followed 253 workers in a British shipyard. The study observed 17 deaths from asbestos-linked malignant disease and pleural plaques were present on the chest X-ray in 21% of these workers[21]. The extent of exposure was significant. Between 1999 and 2005 there were 1,879 declared cases of asbestos-linked occupational disease in one French shipbuilding yard[22]. 22% of CT scans carried out routinely on workers over the age of 50 years showed disease with plaque or pleural thickening. The occupations with the most exposure are boilermakers (27%), pipefitters and welders. In a 2012 study, Bianchi included 2776 people who worked in Monfalcone shipyards in 1942. In this population, 18% have a diagnosis of mesothelioma and in the population of 14 years old workers in 1942 (557 workers), 6 have declared mesothelioma[23]. Those who worked in shipyards before 1980 must be monitored carefully, but this should not obscure the fact that there is still a risk, mainly in ship repair.
Refractory ceramic fibres used as a replacement for asbestos have similar biopersistance characteristics and are classed as 2B carcinogens by the International Agency for Research on Cancer IARC. Care is needed to monitor the effect in coming years.
Hydrocarbons
Aromatic hydrocarbons are found in solvents that contain toluene and xylene and these are widely used by engineers and painters, as is styrene, which is used in boatbuilding[24]. These are central nervous system depressants, and carry a long-term risk of diseases such as attention deficit hyperactivity disorder (ADHD). They are irritant to the skin and respiratory system, and in large quantities carry a risk of pulmonary oedema, anorexia and abdominal problems. Toluene is classed as a teratogen and carcinogen class 2 in European Union (reglement Classification Labelling Packaging and kidney conditions such as glomerulopathy have been described[25] [26]. Exposure to carcinogens such as benzene, a leukemogen, and trichloroethylene (which causes kidney cancer) also occurred before these substances were banned[27]. Occupational exposure can be direct by use of a product, or indirect, via the products being transported as petroleum derivatives[28].
Styrene is used in the polymerisation of polyester resins, and represents 40% of the weight of these resins24 It is classed as a 2B carcinogen by the IARC, because of the possible risk of effects on the blood.
Paints
In painting, there is exposure to aromatic solvents such as xylene and toluene, which are present in paints and solvents used to clean equipment. There are also ketones, aldehydes, esters and glycols. Low molecular weight hydrocarbons are asphyxiants and central nervous system depressants whilst ethylene glycol acetates carry a risk of haematological disorders such as bone marrow depression. Exposure is increased when work is done in confined spaces such as in ballast tanks and fuel tanks, as demonstrated by Kim, with mean levels which were 4 times higher than for painters working on deck[29].
Hand washing in solvents still occurs. Painters may therefore have been exposed to high concentrations of trichloroethylene until the 1990s. This is a definite carcinogen according to the IARC, In addition to high proportions of xylene, anti-corrosion and anti-fouling paints contain epoxies that cause skin sensitivity, pigments and antifouling molecules. Since tributyltin (TBT) was banned in 2003, pigments mainly consist of copper oxides, and zinc, titanium, nickel and iron oxides. These pigments irritate the respiratory tract, and copper may cause an increased risk of cancer of the urinary tract. There is little human toxicology data on these substances. Respiratory exposure experienced by ship painters was evaluated, and exposure to copper was 3 mg/m3 for spray-painting and 0.8 mg/m3 for sandblasting, 0.14 for Dichlofluanide[30] and 52.6 and 33.2 ppm for xylene and ethylbenzene respectively. Grandjean found blood and plasma nickel levels of 5.2 µg/dL in a population of ship painters, levels that were statistically greater than for a group of welders[31]. As Chang proved[32], wearing respiratory masks reduces the concentrations of xylene and ethylbenzene to which painters are exposed by 96% and 94% respectively.
Additional references:
1-E C. Alexopoulos, T Tsouvaltzidou. Hearing loss in shipyard employees. Indian J Occup Environ Med. 2015 Jan-Apr; 19(1): 14–18. doi: 10.4103/0019-5278.157000
2- Sliwinska-Kowalska M. Exposure to organic solvent mixture and hearing loss: literature overview. Int J Occup Med Environ Health. 2007;20(4):309-14. Review
3- Cherniack M, Brammer AJ, Lundstrom R, Meyer J et al. Segmental nerve conduction velocity in vibration-exposed shipyard workers. Int arch Occup Environ Health. 2004 Apr;77(3):159-76
4- Alexoploulos EC, Konstantinou EC, Bakoyannis G, Tanagra D, Burdof A. Risk factors for sickness absence due to low back pain and prognostic factors for return to work in a cohort of shipyard workers. Eur Spine J.2008;17:1185-1192.
5-Park BC, Cheong HK, Kim EA, Kim SG. Risk Factors of Work-related Upper Extremity Musculoskeletal Disorders in Male Shipyard Workers: Structural Equation Model Analysis. Saf Health Work. 2010 Dec;1(2):124-33. doi: 10.5491/SHAW.2010.1.2.124.
6-Tomioka K, Natori Y, Kumagai S, Kurumatani N. An updated historical cohort mortality study of workers exposed to asbestos in a refitting shipyard, 1947-2007.Int Arch Occup Environ Health. 2011 Dec;84(8):959-67. doi: 10.1007/s00420-011-0655-2.
7-Lee KH , Ichiba M, Zhang J, Tomokuni K et al. Multiple biomarkers study in painters in a shipyard in Korea. Mutat Res. 2003 Sep 9;540(1):89-98.
8- Kim V, Lee NR, Kim KS, Yag Js et al. Evaluation of exposure to ethylene glycol monoethyl ether acetates and their possible haematological effects on shipyard painters. Occup Environ Med 1999;56:378-382.
9-Lucas D, Jegaden D, Loddé B. Toxicologie des peintures navales (peintures de coques et antifouling) In Textbook de Médecine Maritime Ed Lavoisier. Paris Chap 29 ; 2015 : 251-59.
10- Wastensson G1, Sallsten G, Bast-Pettersen R, Barregard L. Neuromotor function in ship welders after cessation of manganese exposure. Int Arch Occup Environ Health. 2012 Aug;85(6):703-13. doi: 10.1007/s00420-011-0716-6.
11- Jegaden D. santé, sécurité. Modèles applicables en médecine maritime. In Textbook de Médecine Maritime Ed Lavoisier. Paris Chap 34 ; 2015 : 291-300.
E.9.2 Shipbreaking and wreck removal
This sector of the industry has developed massively in recent years as a response to
- the increase in the number of ships, especially big ships such as supertankers and container ships,
- the price of steel and
- new environmental regulations.
The Nairobi International Convention on the Removal of Wrecks, published by the International Maritime Organisation (IMO)[33] will provide the legal basis for states to remove, or have removed, shipwrecks that may have the potential to adversely affect the safety of lives, goods and property at sea, as well as the marine environment. The convention was adopted in 2007 and entry into force the 14 april 2015. Clearly stated is the obligation for the registered owners of a ship to remove a wreck at their own expense. Some wrecks are removed after accidents and others broken up and recycled are bat the end of the vessel’s life. From a health perspective, major problems are not far from workers in this industry. There is a high rate of occupational accidents resulting in trauma, especially when removing is done at sea or on a beach/rocks, with an explosion and subsequent fire. Other physical risks include exposure to:
- noise and vibrations
- chemicals including asbestos in older vessels and lead in old paints
- gases in confined spaces like tanks
- welding fumes
- hypoxia when cutting a ship’s hull
Many sites for shipbreaking are in countries with a low level of occupational health legislation, including, for example, no ban on the use of or exposure to asbestos or lead.
Whilst studies have been published on the environmental impact of the removal of wrecks, no studies have been yet published on the impact on workers in this industry. Much research in this area is needed.
E.9.3 Crew health and safety considerations
In shipbuilding, but more, in the ship repairing yard, occupational safety and health impact for crew is from coactivity. During maintenance, most of the seafarers stay onboard and have specific tasks to do. Relevant safety coordination between ships crew and shipyard workers is the gold standard. A very open communication between the ship owner, health and safety staff and shipyard production service is the first step. (linked to chapter XX) Docking is one of the most accident prone work steps with deaths amongst crew, port and ship facilities workers. Another problem is multinational and multicultural crew. Further information is available in Ch xxx and there are no big differences in the ship building and repairing sector.
[1] The Shipbuilding and Ship repair sectors in the candidate countries : Poland, Estonia, the Czech Republic, Hungary and Slovenia. Final Report PSE/99/502333.
2https://ec.europa.eu/growth/sectors/maritime-industries/shipbuilding-sector_en
3Lucas D, Loddé B, Pougnet R, Dewitte JD, Bronstein JA, Jegaden D. Study of the pathologies at the origin of sick leaves of more than 30 days in a population of workers of the naval repair in 2009 and 2010. ISMH 12 4-7 june 2013 Brest.
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[29] Kim V, Lee NR, Kim KS, Yag Js et al. Evaluation of exposure to ethylene glycol monoethyl ether acetates and their possible haematological effects on shipyard painters. Occup Environ Med 1999;56:378-382.
[30] Links I, Van Der Jagdt K, Christopher Y et al: Occupational exposure during application and removal of antifouling paints. Annals of Occup Hyg 2007;51(2):207-218
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[32] Chang FK, Chen ML, Cheng SF, Shil TS, Mao IF. Evaluation of dermal absorption and protective effectiveness of respirators for xylene in spray painters. Int Arch Occup Environ Health 2007 Nov;81(2):145-150.
[33] http://www.imo.org/en/About/Conventions/ListOfConventions/Pages/Nairobi-International-Convention-on-the-Removal-of-Wrecks.aspx. Adoption: 18 May, 2007; Entry into force: 14 April 2015