1. Executive introduction: the persistent hazard

The global maritime industry continues to grapple with the profound and deadly historical legacy of asbestos utilization in naval architecture, ship construction, and onboard engineering systems. Despite decades of escalating regulatory bans, exhaustive scientific research into its carcinogenic properties, and a comprehensive understanding of its severe health implications, asbestos remains a critical, pervasive occupational health hazard for seafarers, ship repairers, dry-dock workers, and shipbreaking personnel. The International Labour Organization (ILO), working in close epidemiological conjunction with the World Health Organization (WHO) and the regulatory apparatus of the International Maritime Organization (IMO), has repeatedly and forcefully highlighted the severe, unyielding burden of disease associated with occupational asbestos exposure in the maritime sector.1

The ubiquitous presence of Asbestos-Containing Materials (ACMs) on older vessels, compounded by alarming instances of illicit or inadvertent installation of asbestos-laden replacement parts on newer, ostensibly "asbestos‑free" ships, necessitates the implementation of rigorous, uncompromising shipboard management protocols. In accordance with the foundational principles of the ILO Code of Practice on Safety in the Use of Asbestos, the paramount objective of modern maritime health and safety frameworks is the absolute prevention, rigorous control, and aggressive minimization of human exposure to airborne asbestos fibers.5

2. Topographical distribution: the architectural anatomy of shipboard asbestos

The historical, widespread reliance on asbestos in maritime construction was not an accident of engineering; it was driven by the mineral's unparalleled physicochemical properties. As a naturally occurring silicate mineral, asbestos exists in several forms, primarily chrysotile (white asbestos), amosite (brown asbestos), and crocidolite (blue asbestos).1 Across all its variations, asbestos exhibits exceptional tensile strength, profound chemical inertness, high electrical resistance, and superlative thermal and acoustic insulation capabilities.

2.1 Thermal and acoustic insulation systems in machinery spaces

The engine room, boiler room, and adjacent machinery spaces represent the highest concentration zones for thermal Asbestos-Containing Materials. The extreme operational thermodynamics of marine propulsion plants, where temperatures routinely exceed temp threshold, necessitated aggressive insulation. Historically, asbestos was the premier material utilized as thermal insulation, commonly referred to as lagging, on the exterior shells of main and auxiliary boilers, as well as within economiser units.9 The high-pressure steam pipework that intricately webs throughout the engine room, alongside the massive main engine exhaust manifolds, were frequently insulated with dense asbestos-containing plaster, highly compressed magnesia blocks laced with amosite fibers, or woven asbestos blankets.9

2.2 Structural fire protection and vessel compartmentalization

A-60 class fire-retardant bulkhead panels and deck plates frequently featured a dense core of amosite or chrysotile asbestos tightly bound within a rigid calcium silicate matrix.9 One of the most insidious applications of structural asbestos was the widespread use of spray-applied fireproofing, often referred to in the industry as "limpet" asbestos – a highly friable, easily disturbed mixture sprayed directly onto bare steel bulkheads, deckheads, and deep within inaccessible pipe chases.9

2.3 Mechanical components, flanged joints, and friction materials

Across the vast, complex networks of fuel oil, high-pressure steam, main engine cooling water, and exhaust piping, countless flanged joints were historically sealed utilizing robust, asbestos-reinforced compressed fiber gaskets.9 The heavy‑duty brake linings and friction clutch facings for massive anchor windlasses, high‑tension mooring winches, and critical lifeboat davit falls were predominantly composed of densely woven asbestos infused with high-temperature resins.9

2.4 High-voltage electrical installations

The vessel's main electrical switchboards, alongside emergency switchboard panels, frequently utilized rigid asbestos cement boards as the primary backing for mounting highly conductive electrical components.9 Heavy‑duty arc chutes, the critical safety devices designed to physically quench the explosive electrical arc generated when high‑power circuit breakers trip under load, were routinely constructed from heavily compacted, heat‑resistant asbestos compounds.9

2.5 Accommodation outfitting and general consumables

Decorative deck coverings, including rigid vinyl floor tiles, softer rubberized deck tiles, and the specific mastic adhesives utilized to bond them to steel decks, frequently contained significant percentages of chrysotile asbestos.9 Older welding blankets, emergency fire blankets, and protective gloves used by engine crew were, for decades, woven entirely from nearly pure asbestos fibers.9

Table 1 — Typical shipboard asbestos‑containing materials (ACMs)

3. Pathophysiology and epidemiology of asbestos‑related diseases

The International Agency for Research on Cancer (IARC) classifies all commercial forms of asbestos as Group 1 human carcinogens.1 There is no medically recognized safe level of exposure. When ACMs are disturbed, they release microscopic, crystalline, needle‑like fibers that penetrate deep into the lung tissue, causing frustrated phagocytosis, chronic inflammation, DNA damage, and fibrogenesis or malignant transformation.

3.1 Asbestosis: progressive pulmonary fibrosis

Asbestosis is a chronic, non‑malignant but relentlessly progressive fibrotic interstitial lung disease. The widespread, irreversible scarring destroys alveolar architecture, drastically reducing lung elasticity and impairing oxygen diffusion.9 Clinically, seafarers present with exertional dyspnea, persistent cough, bilateral crackles, and digital clubbing.

3.2 Bronchogenic carcinoma: asbestos‑induced lung cancer

Occupational exposure to airborne asbestos fibers is a primary driver of lung cancer among maritime workers. The statistical risk is heavily influenced by cumulative dose, and there is a profound multiplicative synergy with tobacco smoking (up to 90‑fold increased risk).4

3.3 Malignant mesothelioma: the defining maritime malignancy

Malignant mesothelioma is an exceedingly rare, aggressive, and virtually invariably fatal cancer arising from the mesothelium. It is not strongly dose‑dependent – even transient or secondary exposure can trigger the disease. Latency period is extraordinarily long: 10 to 50 years.4 The median survival after diagnosis is merely 9 to 12 months.

3.4 Benign pleural pathologies

Pleural plaques (localized hyaline fibrosis) are the most common manifestation. Diffuse pleural thickening can bind the lung and restrict respiration. Benign asbestos pleural effusion (BAPE) may be the first warning sign.9

3.5 The massive global epidemiological burden

Combined ILO/WHO estimates: approximately 27,000 mesothelioma deaths annually (2019) and over 200,000 asbestos‑related deaths overall.1,4 Millions of Disability‑Adjusted Life Years (DALYs) are lost due to legacy asbestos in the global fleet.

4. International regulatory governance: ILO and IMO safety mandates

4.1 ILO Convention No.162 (1986) and the 2006 resolution

Key provisions: mandatory substitution, strict employer accountability, prohibition of secondary contamination (taking home work clothes), and mandatory information/training.6,7,15 The 2006 ILO resolution called for absolute elimination of all forms of asbestos globally.

4.2 IMO SOLAS regulations & Inventory of Hazardous Materials (IHM)

Ships constructed before July 2002: permitted to retain ACMs if non‑friable and managed per MSC.1/Circ.1045.2
July 2002 – Dec 2010: new installations prohibited, narrow exceptions (high‑temp joints, linings for fluid circulation exceeding pressure threshold Pa and temp threshold).12
From 1 Jan 2011: absolute prohibition, no exceptions.11

If non‑compliant ACMs are found, flag state must be notified, and removal by professional abatement must occur within three years; interim risk‑based monitoring is mandatory.12

Table 2 — SOLAS regulatory eras & asbestos mandates

5. Operational protocols: precautions for emergency shipboard repairs

Under normal circumstances, removal must be done by shore‑based abatement contractors. However, if a critical failure threatens vessel safety (e.g., ruptured steam flange), the crew may need to intervene. The following phased precautions are derived from ILO codes and IMO circulars.2,5

Detailed emergency repair phases (ILO/IMO sequence)

Phase V post‑repair: Meticulous documentation in SMS, retention of personal exposure records, and decades‑long medical surveillance (tracking significant threshold shifts).19

6. Conclusion

The eradication of asbestos from the global maritime ecosystem remains an ongoing, multi‑generational challenge. While IMO SOLAS regulations have halted legal introduction of new ACMs, the staggering volume of legacy asbestos embedded in older tonnage ensures the hazard persists. The ILO's stark epidemiological data — hundreds of thousands of annual deaths driven by mesothelioma and lung cancer — underscores that complacency is lethal. Effective management relies on rigorous IHM maintenance, strict adherence to ILO Convention 162, and disciplined execution of emergency protocols. The international mandate is unambiguous: identify proactively, contain rigorously, and mitigate absolutely.

Works cited

This webpage is an information resource based on ILO/IMO guidelines. Always consult current regulations and licensed specialists for abatement.