Ungs, Timothy J.

Ungs, Timothy J.

Address: US Coast Guard Headquarters, 2100 2nd Street, SW, Washington, DC 20593

Country: United States

Phone: 1 (202) 267-0692

Fax: 1 (202) 267-4355

Education: MD; MS

The very definition of the maritime setting is work and life that takes place in or around a watery world (e.g., ships and barges, docks and terminals). Work and life activities must first accommodate the macro-environmental conditions of the oceans, lakes or waterways in which they take place. Vessels serve as both workplace and home, so most habitat and work exposures are coexistent and inseparable.

The maritime industry comprises a number of sub-industries, including freight transportation, passenger and ferry service, commercial fishing, tankships and barge shipping. Individual maritime sub-industries consist of a set of merchant or commercial activities that are characterized by the type of vessel, targeted goods and services, typical practices and area of operations, and community of owners, operators and workers. In turn, these activities and the context in which they take place define the occupational and environmental hazards and exposures experienced by maritime workers.

Organized merchant maritime activities date back to the earliest days of civilized history. The ancient Greek, Egyptian and Japanese societies are examples of great civilizations where the development of power and influence was closely associated with having an extensive maritime presence. The importance of maritime industries to development of national power and prosperity has continued into the modern era.

The dominant maritime industry is water transportation, which remains the primary mode of international trade. The economies of most countries with ocean borders are heavily influenced by the receipt and export of goods and services by water. However, national and regional economies heavily dependent on the transport of goods by water are not limited to those which border oceans. Many countries removed from the sea have extensive networks of inland waterways.

Modern merchant vessels may process materials or produce goods as well as transport them. Globalized economies, restrictive land use, favourable tax laws and technology are among the factors which have spurred the growth of vessels that serve as both factory and means of transportation. Catcher-processor fishing vessels are a good example of this trend. These factory ships are capable of catching, processing, packaging and delivering finished sea food products to regional markets, as discussed in the chapter Fishing industry.

Merchant Transport Vessels

Similar to other transport vehicles, the structure, form and function of vessels closely parallel the vessel’s purpose and major environmental circumstances. For example, craft that transport liquids short distances on inland waterways will differ substantially in form and crew from those that carry dry bulk on trans-oceanic voyages. Vessels can be free moving, semi-mobile or permanently fixed structures (e.g., offshore oil-drilling rigs) and be self-propelled or towed. At any given time, existing fleets are comprised of a spectrum of vessels with a wide range of original construction dates, materials and degrees of sophistication.

Crew size will depend on the typical duration of trip, vessel purpose and technology, expected environmental conditions and sophistication of shore facilities. Larger crew size entails more extensive needs and elaborate planning for berthing, dining, sanitation, health care and personnel support. The international trend is toward vessels of increasing size and complexity, smaller crews and expanding reliance on automation, mechanization and containerization. Table 1 provides a categorization and descriptive summary of merchant vessel types.

Table 1. Merchant vessel types.

Vessel types


Crew size

Freight ships


Bulk carrier




Break bulk








Ore, bulk, oil  (OBO)






Roll-on roll- off (RORO)

Large vessel (200-600 feet (61-183 m)) typified by large open cargo holds and many voids; carry bulk cargoes such as grain and ore; cargo is loaded by chute, conveyor or shovel


Large vessel (200-600 feet (61-183 m)); cargo carried in bales, pallets, bags or boxes; expansive holds with between decks; may have tunnels



Large vessel (200-600 (61-183 m)) with open holds; may or may not have booms or cranes to handle cargo; containers are 20-40 feet (6.1-12.2 m) and stackable



Large vessel (200-600 feet (61-183 m)); holds are expansive and shaped to hold bulk ore or oil; holds are water tight, may have pumps and piping; many voids



Large vessel (200-600 feet (61-183 m)) with big sail area; many levels; vehicles can be self loading or boomed aboard



Large vessel (200-600 feet (61-183 m)) with big sail area; many levels; can carry other cargo in addition to vehicles




















Tank ships










Large vessel (200-1000 feet (61-305 m)) typified by stern house piping on deck; may have hose handling booms and large ullages with many tanks; can carry crude or processed oil, solvents and other petroleum products


Large vessel (200-1000 feet (61-305 m)) similar to oil tankship, but may have additional piping and pumps to handle multiple cargoes simultaneously; cargoes can be liquid, gas, powders or compressed solids


Usually smaller (200-700 feet (61-213.4 m)) than typical tankship, having fewer tanks, and tanks which are pressurized or cooled; can be chemical or petroleum products such as liquid natural gas; tanks are usually covered and insulated; many voids, pipes and pumps









Tug boats

Small to mid-size vessel (80-200 feet (24.4-61 m));  harbour, push boats, ocean going



Mid-size vessel (100-350 feet (30.5-106.7 m)); can be tank, deck, freight or vehicle; usually not manned or self-propelled; many voids


Drillships and rigs

Large, similar profile to bulk carrier; typified by large derrick; many voids, machinery, hazardous cargo and large crew; some are towed, others self propelled



All sizes (50-700 feet (15.2-213.4 m)); typified by large number of crew and passengers (up to 1000+)



Morbidity and Mortality in the Maritime Industries

Health care providers and epidemiologists are often challenged to distinguish adverse health states due to work-related exposures from those due to exposures outside the workplace. This difficulty is compounded in the maritime industries because vessels serve as both workplace and home, and both exist in the greater environment of the maritime milieu itself. The physical boundaries found on most vessels result in close confinement and sharing of workspaces, engine-room, storage areas, passageways and other compartments with living spaces. Vessels often have a single water, ventilation or sanitation system that serves both work and living quarters.

The social structure aboard vessels is typically stratified into vessel officers or operators (ship’s master, first mate and so on) and remaining crew. Ship officers or operators are generally relatively more educated, affluent and occupationally stable. It is not uncommon to find vessels with crew members of an entirely different national or ethnic background from that of the officers or operators. Historically, maritime communities are more transient, heterogeneous and somewhat more independent than non-maritime communities. Work schedules aboard ship are often more fragmented and intermingled with non-work time than are land-based employment situations.

These are some reasons why it is difficult to describe or quantify health problems in the maritime industries, or to correctly associate problems with exposures. Data on maritime worker morbidity and mortality suffer from being incomplete and not representative of entire crews or sub-industries. Another shortfall of many data sets or information systems that report on the maritime industries is the inability to distinguish among health problems due to work, vessel or macro-environmental exposures. As with other occupations, difficulties in capturing morbidity and mortality information is most obvious with chronic disease conditions (e.g., cardiovascular disease), particularly those with a long latency (e.g., cancer).

Review of 11 years (1983 to 1993) of US maritime data demonstrated that half of all fatalities due to maritime injuries, but only 12% of non-fatal injuries, are attributed to the vessel (i.e., collision or capsizing). The remaining fatalities and non-fatal injuries are attributed to personnel (e.g., mishaps to an individual while aboard ship). Reported causes of such mortality and morbidity are described in figure 1 and figure 2 respectively. Comparable information on non-injury-related mortality and morbidity is not available.

Figure 1. Causes of leading fatal unintentional injuries attributed to personal reasons (US maritime industries 1983-1993).


Figure 2. Causes of leading non-fatal unintentional injuries attributed to personal reasons (US maritime industries 1983-1993).


Combined vessel and personal US maritime casualty data reveal that the highest proportion (42%) of all maritime fatalities (N = 2,559), occurred among commercial fishing vessels. The next highest were among towboats/barges (11%), freight ships (10%) and passenger vessels (10%).

Analysis of reported work-related injuries for the maritime industries shows similarities to patterns reported for the manufacturing and construction industries. Commonalities are that most injuries are due to falls, being struck, cuts and bruises or muscular strains and overuse. Caution is needed when interpreting these data, however, as there is reporting bias: acute injuries are likely to be over-represented and chronic/latent injuries, which are less obviously connected to work, under-reported.

Occupational and Environmental Hazards

Most health hazards found in the maritime setting have land-based analogs in the manufacturing, construction and agricultural industries. The difference is that the maritime environment constricts and compresses available space, forcing close proximity of potential hazards and the intermingling of living quarters and workspaces with fuel tanks, engine and propulsion areas, cargo and storage spaces.

Table 2 summaries health hazards common across different vessel types. Health hazards of particular concern with specific vessel types are highlighted in table 3. The following paragraphs of this section expand discussion of selected environmental, physical and chemical, and sanitation health hazards.

Table 2. Health hazards common across vessel types.





Unguarded or exposed moving objects or their parts, which strike, pinch, crush or entangle. Objects can be mechanized (e.g., fork-lift) or simple (hinged door).

Winches, pumps, fans, drive shafts, compressors, propellers, hatches, doors, booms, cranes, mooring lines, moving cargo


Static (e.g., batteries) or active (e.g., generators) sources of electricity, their distribution system (e.g., wiring) and powered devices (e.g., motors), all of which can cause direct electrical-induced physical injury

Batteries, vessel generators, dockside electrical sources, unprotected or ungrounded electric motors (pumps, fans, etc.), exposed wiring, navigation and communication electronics


Heat- or cold-induced injury

Steam pipes, cold storage spaces, power plant exhaust, cold- or warm-weather exposure above deck


Adverse auditory and other physiological problems due to excessive and prolonged sound energy

Vessel propulsion system, pumps, ventilation fans, winches, steam-powered devices, conveyor belts


Slips, trips and falls resulting in kinetic-energy-induced injuries

Steep ladders, deep vessel holds, missing railings, narrow gangways, elevated platforms


Acute and chronic disease or injury resulting from exposure to organic or inorganic chemicals and heavy metals

Cleaning solvents, cargo, detergents, welding, rusting/corrosion processes, refrigerants, pesticides, fumigants


Disease related to unsafe water, poor food practices or improper waste disposal

Contaminated potable water, food spoilage, deteriorated vessel waste system


Disease or illness causes by exposure to living organisms or their products

Grain dust, raw wood products, cotton bales, bulk fruit or meat, seafood products, communicable disease agents


Injury due to non-ionizing radiation

Intense sunlight, arc welding, radar, microwave communications


Interpersonal violence

Assault, homicide, violent conflict among crew

Confined space

Toxic or anoxic injury resulting from entering an enclosed space with limited entry

Cargo holds, ballast tanks, crawl spaces, fuel tanks, boilers, storage rooms, refrigerated holds

Physical work

Health problems due to overuse, disuse or unsuitable work practices

Shovelling ice in fish tanks, moving awkward cargo in restricted spaces, handling heavy mooring lines, prolonged stationary watch standing


Table 3. Notable physical and chemical hazards for specific vessel types.

Vessel Types


Tank vessels

Benzene and various hydrocarbon vapours, hydrogen sulphide off-gassing from crude oil, inert gases used in tanks to create oxygen-deficient atmosphere for explosion control, fire and explosion due to combustion of hydrocarbon products

Bulk cargo vessels

Pocketing of fumigants used on agricultural products, personnel entrapment/suffocation in loose or shifting cargo, confined space risks in conveyor or man tunnels deep in vessel, oxygen deficiency due to oxidation or fermentation of cargo

Chemical carriers

Venting of toxic gases or dusts, pressurized air or gas release, leakage of hazardous substances from cargo holds or transfer pipes, fire and explosion due to combustion of chemical cargoes

Container ships

Exposure to spills or leakage due to failed or improperly stored hazardous substances; release of agricultural inerting gases; venting from chemical or gas containers; exposure to mislabeled substances that are hazardous; explosions, fire or toxic exposures due to mixing of separate substances to form a dangerous agent (e.g., acid and sodium cyanide)

Break bulk vessels

Unsafe conditions due to shifting of cargo or improper storage; fire, explosion or toxic exposures due to mixing of incompatible cargoes; oxygen deficiency due to oxidation or fermentation of cargoes; release of refrigerant gases

Passenger ships

Contaminated potable water, unsafe food preparation and storage practices, mass evacuation concerns, acute health problems of individual passengers

Fishing vessels

Thermal hazards from refrigerated holds, oxygen deficiency due to decomposition of seafood products or use of antioxidant preservatives, release of refrigerant gases, entanglement in netting or lines, contact with dangerous or toxic fish or sea animals



Arguably the most characteristic exposure defining the maritime industries is the pervasive presence of the water itself. The most variable and challenging of water environments is the open ocean. Oceans present constantly undulating surfaces, extremes of weather and hostile travel conditions, which combine to cause constant motion, turbulence and shifting surfaces and can result in vestibular disturbances (motion sickness), object instability (e.g., swinging latches and sliding gear) and the propensity to fall.

Humans have limited capability to survive unaided in open water; drowning and hypothermia are immediate threats upon immersion. Vessels serve as platforms that permit the human presence at sea. Ships and other water craft generally operate at some distance from other resources. For these reasons, vessels must dedicate a large proportion of total space to life support, fuel, structural integrity and propulsion, often at the expense of habitability, personnel safety and human factor considerations. Modern supertankers, which provide more generous human space and liveability, are an exception.

Excessive noise exposure is a prevalent problem because sound energy is readily transmitted through a vessel’s metallic structure to nearly all spaces, and limited noise attenuation materials are used. Excessive noise can be nearly continuous, with no available quiet areas. Sources of noise include the engine, propulsion system, machinery, fans, pumps and the pounding of waves on the vessel hull.

Mariners are an identified risk group for developing skin cancers, including malignant melanoma, squamous cell carcinoma and basal cell carcinoma. The increased risk is due to excess exposure to direct and water-surface-reflected ultraviolet solar radiation. Body areas of particular risk are exposed parts of the face, neck, ears and forearms.

Limited insulation, inadequate ventilation, internal sources of heat or cold (e.g., engine rooms or refrigerated spaces) and metallic surfaces all account for potential thermal stress. Thermal stress compounds physiological stress from other sources, resulting in reduced physical and cognitive performance. Thermal stress that is not adequately controlled or protected against can result in heat- or cold-induced injury.

Physical and chemical hazards

Table 3 highlights hazards unique or of particular concern to specific vessel types. Physical hazards are the most common and pervasive hazard aboard vessels of any type. Space limitations result in narrow passageways, limited clearance, steep ladders and low overheads. Confined vessel spaces means that machinery, piping, vents, conduits, tanks and so forth are squeezed in, with limited physical separation. Vessels commonly have openings that allow direct vertical access to all levels. Inner spaces below the surface deck are characterized by a combination of large holds, compact spaces and hidden compartments. Such physical structure places crew members at risk for slips, trips and falls, cuts and bruises, and being struck by moving or falling objects.

Constricted conditions result in being in close proximity to machinery, electrical lines, high-pressure tanks and hoses, and dangerously hot or cold surfaces. If unguarded or energized, contact can result in burns, abrasions, lacerations, eye damage, crushing or more serious injury.

Since vessels are basically a composite of spaces housed within a water-tight envelope, ventilation can be marginal or deficient in some spaces, creating a hazardous confined space situation. If oxygen levels are depleted or air is displaced, or if toxic gases enter these confined spaces, entry can be life threatening.

Refrigerants, fuels, solvents, cleaning agents, paints, inert gases and other chemical substances are likely to be found on any vessel. Normal ship activities, such as welding, painting and trash burning can have toxic effects. Transport vessels (e.g., freight ships, container ships and tank ships) can carry a host of biological or chemical products, many of which are toxic if inhaled, ingested or touched with the bare skin. Others can become toxic if allowed to degrade, become contaminated or mix with other agents.

Toxicity can be acute, as evidenced by dermal rashes and ocular burns, or chronic, as evidenced by neurobehavioural disorders and fertility problems or even carcinogenic. Some exposures can be immediately life-threatening. Examples of toxic chemicals carried by vessels are benzene-containing petrochemicals, acrylonitrile, butadiene, liquefied natural gas, carbon tetrachloride, chloroform, ethylene dibromide, ethylene oxide, formaldehyde solutions, nitropropane, o-toluidine and vinyl chloride.

Asbestos remains a hazard on some vessels, principally those constructed prior to the early 1970s. The thermal insulation, fire protection, durability and low cost of asbestos made this a preferred material in ship building. The primary hazard of asbestos occurs when the material becomes airborne when it is disturbed during renovations, construction or repair activities.

Sanitation and communicable disease hazards

One of the realities aboard ship is that the crew is often in close contact. In the work, recreation and living environments, crowding is often a fact of life that heightens the requirement for maintaining an effective sanitation programme. Critical areas include: berthing spaces, including toilet and shower facilities; food service and storage areas; laundry; recreation areas; and, if present, the barbershop. Pest and vermin control is also of critical importance; many of these animals can transmit disease. There are many opportunities for insects and rodents to infest a vessel, and once entrenched they are very difficult to control or eradicate, especially while underway. All vessels must have a safe and effective pest control programme. This requires training of individuals for this task, including annual refresher training.

Berthing areas must be kept free of debris, soiled laundry and perishable food. Bedding should be changed at least weekly (more often if soiled), and adequate laundry facilities for the size of the crew should be available. Food service areas must be rigorously maintained in a sanitary manner. The food service staff must receive training in proper techniques of food preparation, storage and galley sanitation, and adequate storage facilities must be provided aboard ship. The staff must adhere to recommended standards to ensure that food is prepared in a wholesome manner and is free of chemical and biological contamination. The occurrence of a food-borne disease outbreak aboard a vessel can be serious. A debilitated crew cannot carry out its duties. There may be insufficient medication to treat the crew, especially underway, and there may not be competent medical staff to care for the ill. In addition, if the ship is forced to change its destination, there may be significant economic loss to the shipping company.

The integrity and maintenance of a vessel’s potable water system is also of vital importance. Historically, water-borne outbreaks aboard ship have been the most common cause of acute disability and death among crews. Therefore, the potable water supply must come from an approved source (wherever possible) and be free from chemical and biological contamination. Where this is not possible, the vessel must have the means to effectively decontaminate the water and render it potable. A potable water system must be protected against contamination by every known source, including cross-contaminations with any non-potable liquids. The system also must be protected from chemical contamination. It must be cleaned and disinfected periodically. Filling the system with clean water containing at least 100 parts per million (ppm) of chlorine for several hours and then flushing the entire system with water containing 100 ppm chlorine is effective disinfection. The system should then be flushed with fresh potable water. A potable water supply must have at least 2 ppm residual of chlorine at all times, as documented by periodic testing.

Communicable disease transmission aboard ship is a serious potential problem. Lost work time, the cost of medical treatment and the possibility of having to evacuate crew members make this an important consideration. Besides the more common disease agents (e.g., those that cause gastroenteritis, such as Salmonella, and those that cause upper respiratory disease, such as the influenza virus), there has been a re-emergence of disease agents that were thought to be under control or eliminated from the general population. Tuberculosis, highly pathogenic strains of Escherichia coli and Streptococcus, and syphilis and gonorrhoea have reappeared in increasing incidence and/or virulence.

In addition, previously unknown or uncommon disease agents such as the HIV virus and the Ebola virus, which are not only highly resistant to treatment, but highly lethal, have appeared. It is therefore important that assessment be made of appropriate crew immunization for such diseases as polio, diphtheria, tetanus, measles, and hepatitis A and B. Additional immunizations may be required for specific potential or unique exposures, since crew members may have occasion to visit a wide variety of ports around the world and at the same time come in contact with a number of disease agents.

It is vital that crew members receive periodic training in the avoidance of contact with disease agents. The topic should include blood-borne pathogens, sexually transmitted diseases (STDs), food- and water-borne diseases, personal hygiene, symptoms of the more common communicable diseases and appropriate action by the individual on discovering these symptoms. Communicable disease outbreaks aboard ship can have a devastating effect on the vessel’s operation; they can result in a high level of illness among the crew, with the possibility of serious debilitating disease and in some cases death. In some instances, vessel diversion has been required with resultant heavy economic losses. It is in the best interest of the vessel owner to have an effective and efficient communicable disease programme.

Hazard Control and Risk Reduction

Conceptually, the principles of hazard control and risk reduction are similar to other occupational settings, and include:

  • hazard identification and characterization
  • inventory and analysis of exposures and at-risk populations
  • hazard elimination or control
  • personnel monitoring and surveillance
  • disease/injury prevention and intervention
  • programme evaluation and adjustment (see table 4).


Table 4. Vessel hazard control & risk-reduction.



Programme development and evaluation

Identify hazards, shipboard and dockside.
Assess nature, extent and magnitude of potential exposures.
Identify crew members at risk.
Determine suitable methods for hazard elimination or control and protection of personnel.
Develop health surveillance and reporting system.
Evaluate and follow at-risk members’ health status.
Measure programme effectiveness.
Adapt and modify programme.

Hazard identification

Inventory shipboard chemical, physical, biological, and environmental hazards, in both work and living spaces (e.g., broken railings, use and storage of cleaning agents, presence of asbestos).
Investigate hazards of cargo and those dockside.

Assessment of exposure

Understand work practices and job tasks (prescribed as well as those actually done).
Qualify and quantify exposure levels (e.g., number of hours in hazardous cargo hold areas, ambient H2S levels due to off-gassing, type of organisms in potable water, sound levels in ship’s spaces).

Personnel at risk

Review work logs, employment records and monitoring data of entire ship’s complement, both seasonal and permanent.

Hazard control and
personnel protection

Know established and recommended exposure standards (e.g., NIOSH, ILO, EU).
Eliminate hazards where possible (replace live watches in hazardous holds with remote electronic monitoring).
Control hazards that cannot be eliminated (e.g., enclose and isolate winches rather than leave exposed, and post warning signs).
Provide necessary personal protective equipment (wear toxic gas and O2 detectors when entering confined spaces).

Health surveillance

Develop health information gathering and reporting system for all injuries and illnesses (e.g., maintain a ship’s daily binnacle).

Monitor crew health

Establish occupational medical monitoring, determine performance standards, and establish fitness-for-work criteria (e.g., pre-placement and periodic pulmonary testing of crew handling grain).

Hazard control and risk reduction effectiveness

Devise and set priorities for goals (e.g., reduce shipboard falls).
Set and measure outcomes toward goals (reduce annual number of days crew members not able to work due to falls aboard ship).
Determine effectiveness of efforts in achieving goals.

Programme evolution

Modify prevention and control activities based on changing circumstances and prioritization.


To be effective, however, the means and methods to implement these principles must be tailored to the specific maritime arena of interest. Occupational activities are complex and take place in integrated systems (e.g., vessel operations, employee/employer associations, commerce and trade determinants). The key to prevention is to understand these systems and the context in which they take place, which requires close cooperation and interaction between all organizational levels of the maritime community, from general deck hand through vessel operators and company upper management. There are many government and regulatory interests that impact the maritime industries. Partnerships between government, regulators, management and workers are essential for meaningful programmes for improving the health and safety status of the maritime industries.

The ILO has established a number of Conventions and Recommendations relating to shipboard work, such as the Prevention of Accidents (Seafarers) Convention, 1970 (No. 134), and Recommendation, 1970 (No. 142), the Merchant Shipping (Minimum Standards) Convention, 1976 (No. 147), the Merchant Shipping (Improvement of Standards) Recommendation, 1976 (No. 155), and the Health Protection and Medical Care (Seafarers) Convention, 1987 (No. 164). The ILO has also published a Code of Practice regarding the prevention of accidents at sea (ILO 1996).

Approximately 80% of vessel casualties are attributed to human factors. Similarly, the majority of reported injury-related morbidity and mortality have human factor causes. Reduction in maritime injury and death requires successful application of principles of human factors to work and life activities aboard vessels. Successful application of human factors principles means that vessel operations, vessel engineering and design, work activities, systems and management policies are developed that integrate human anthropometrics, performance, cognition and behaviours. For example, cargo loading/unloading presents potential hazards. Human factor considerations would highlight the need for clear communication and visibility, ergonomic matching of worker to task, safe separation of workers from moving machinery and cargo and a trained workforce, well acquainted with work processes.

Prevention of chronic diseases and adverse health states with long latency periods is more problematic than injury prevention and control. Acute injury events generally have readily recognized cause-effect relationships. Also, the association of injury cause and effect with work practices and conditions is usually less complicated than for chronic diseases. Hazards, exposures and health data specific to the maritime industries are limited. In general, health surveillance systems, reporting and analyses for the maritime industries are less developed than those for many of their land-based counterparts. The limited availability of chronic or latent disease health data specific to maritime industries hinders development and application of targeted prevention and control programmes.



Oceans, lakes, rivers and other large bodies of water present extremes of environmental conditions demanding the maximum in human performance. The defining attribute that characterizes health and safety hazards of maritime rescues is the pervasive presence of the water itself.

Maritime rescues share many of the health and safety hazards experienced in land-based rescues. The risk of communicable disease transmission, exposure to toxic substances, threat of interpersonal violence and exposure to various physical agents (e.g., noise, vibration, radiation) are examples of commonly shared hazards of water and land rescues. The maritime environment, however, presents several unique or exaggerated hazards compared to the land-based environment. This article will focus on those health and safety hazards most identified with at-sea rescues.

Modes of Response

Before discussing specific health and safety hazards it is important to understand that maritime rescues can take place by either surface vessel or aircraft, or a combination of both. The importance of understanding the mode of response is that characteristics of hazard exposure are determined, in part, by the mode.

Surface vessels typically used in maritime rescues travel at speeds under 40 knots (74.1 km/h), have a relatively limited operational range (under 200 miles (320 km)), are heavily influenced by water surface and weather conditions, are subject to damage by floating debris and generally are not sensitive to weight consideration. Helicopters, the most commonly used aircraft in maritime rescue, can travel in excess of 150 knots (278 km/h), may have an effective operational range of 300 miles (480 km) (more with in-flight refuelling), are more influenced by weather than water conditions and are very sensitive to weight concerns.

Factors that determine the mode of response include distance, urgency, geographic location, resource availability, environmental conditions and character of the responding rescue organization. Factors that tend to favour surface vessel response are closer proximity, lower urgency, proximity to metropolitan or developed regions, milder water surface conditions and a less well developed aviation system and infrastructure. Rescue by air tends to be favoured by longer distances, higher urgency, remoteness from metropolitan or developed regions, harsher water surface conditions, and regions with better-developed aviation systems and infrastructure. Figure 1 and figure 2  show both types of rescue.

Figure 1. Maritime rescue by ship.


US Army

Figure 2. Maritime rescue by helicopter.


US Army

Maritime Hazards

The dominant hazards of maritime rescues are those intrinsic to the watery environment. Rescue personnel are directly exposed to maritime elements and must be prepared for survival themselves.

Drowning is the most common cause of occupation-related death in the maritime environment. People require specialized flotation equipment to survive in water for any length of time. Even the best swimmers require flotation assistance to survive in rough weather. Prolonged (more that several hours) survival in stormy weather is usually impossible without specialized survival suits or rafts. Injuries, reduced level of consciousness, confusion and panic or uncontrolled fear will reduce the likelihood of water survival.

Water is more efficient than air at conducting away body heat. The risk of death due to hypothermia or hypothermia-induced drowning increases rapidly as water temperature decreases below 24 °C. As water temperatures approach freezing, effective survival time is measured in minutes. Prolonged survival in cold water, even when the surface is calm, is possible only with the assistance of specialized survival suits or rafts.

The maritime environment exhibits the extremes of weather conditions. Wind, rain, fog, snow and icing can be severe. Visibility and the ability to communicate can be seriously restricted. Rescuers are constantly at risk for getting wet through wave and splash action, wind-driven rain or spray, and vessel- or aircraft-generated spray. Water, especially salt water, can damage mechanical and electrical equipment essential for vessel or flight operations.

Exposure to salt water can result in skin, mucosal and eye irritation. Ingestion of water-borne infectious micro-organisms (e.g., Vibrio spp.) increases the likelihood of gastro-intestinal disease. The water around rescue sites can be contaminated with pollutants (e.g., sewage) or substances hazardous to human health (e.g., petroleum products). Potential envenomation by water snakes and by various coelenterates (e.g., jellyfish) can occur in areas supporting these organisms. Water and thermal protective clothing is often cumbersome, restrictive and prone to promote heat stress. During sunny conditions, rescuers can experience skin and eye damage due to reflected ultraviolet light.

The surface of large bodies of water, such as the oceans, typically has undulant wave motion with coexistent surface chop. Rescue personnel, therefore, conduct work on a moving platform, which complicates any movement or procedures. Motion sickness is a constant threat. Surface vessels travelling through rough conditions can experience severe pounding and instability which promotes fatigue, an increased likelihood of falls or being struck by falling objects and equipment failure. Aircraft operating in stormy weather experience turbulence that can induce motion sickness, accelerate fatigue and compound the risks of surface-to-air evacuation.

Planning and Prevention

The maritime environment can be extremely hostile. However, the health and safety hazards associated with maritime rescues can be controlled or minimized through careful planning and prevention efforts. Safe and effective rescues can take place.

Rescue organizations must be acutely aware of the nature of the maritime environment, understand the operational characteristics and limitations of response equipment and personnel, practice system safety and provide suitable equipment, training and leadership. Rescue personnel must be in good physical and mental condition, know their equipment and procedures, stay alert, be prepared, remain proficient and understand the specifics of the situation they are dealing with.

Rescue personnel can be involved in vessel or aviation mishaps. The difference between being a rescuer and needing to be rescued can be only a matter of moments. Ultimate mishap survival is dependent on:

  • survival of the impact itself
  • successful egress
  • enduring post-mishap until rescued.


Each stage of mishap survival has its own set of necessary training, equipment, ergonomics and procedures to maximize survival. Maritime rescue personnel usually act in isolation, without immediate backup, and often at long distances from shore. A rule of thumb is for rescuers to have the necessary resources to survive the time it takes to be rescued themselves in the event of their own mishap. Rescuers need to be trained, equipped and prepared to survive in the worst of conditions.



" DISCLAIMER: The ILO does not take responsibility for content presented on this web portal that is presented in any language other than English, which is the language used for the initial production and peer-review of original content. Certain statistics have not been updated since the production of the 4th edition of the Encyclopaedia (1998)."


Part I. The Body
Part II. Health Care
Part III. Management & Policy
Part IV. Tools and Approaches
Part V. Psychosocial and Organizational Factors
Part VI. General Hazards
Part VII. The Environment
Part VIII. Accidents and Safety Management
Part IX. Chemicals
Part X. Industries Based on Biological Resources
Part XI. Industries Based on Natural Resources
Part XII. Chemical Industries
Part XIII. Manufacturing Industries
Part XIV. Textile and Apparel Industries
Part XV. Transport Industries
Part XVI. Construction
Part XVII. Services and Trade
Part XVIII. Guides