Further information on the principles of health risk management is available in Ch xxx
E.2.1 Risk assessment
The health effects of many hazardous agents are well known. In some cases such as noise or commonly used chemicals they have been quantified through studies in onshore populations. These results can be extrapolated, with care, as guides to the risk on board. In some cases, information supplied with items of equipment or chemical products (material safety data sheets) provide practical guidance on necessary precautions. These sources sometimes give recommendations on acceptable levels of exposure. However, information is not always available, particularly on the risks from bulk cargoes in confined spaces or on cleaning operations. In addition, the effect of some complex exposures, for instance welding fumes or flue gas mixtures, will vary markedly depending on circumstances.
A valid risk assessment takes account of both the inherent hazards of the agents present and of the levels and frequency of exposure to them. Where there are uncertainties about hazards, expert assistance may be needed. Where there is uncertainty about exposures then measurements may need to be made. Often a single risk assessment document can be produced that is applicable to a particular operation wherever it is carried out.
E.2.2 Control measures
The outcome of the risk assessment will include a number of measures that need to be applied. This will normally be based on the hierarchy of control approach with the preferred option being the elimination of risk, while the last resort is the use of personal protective equipment. For such measures to be effective, those who could be at risk need to be made aware of the reasons for taking precautions and of their detail. Supervision is required to ensure that all control measures are followed.
More information is available in Ch xxx.
Where risk is significant, measurements of ambient exposure levels may need to be taken. If the risk is immediate, techniques such as using gas detection devices may be appropriate. Direct reading instruments are also useful for longer-term risks such as noise as they show where levels may be dangerous. Often shift long measurements of cumulated exposure are appropriate as many of the limit values for acceptable exposure are given as eight-hour averages.
For some chemical substances it is possible to measure uptake using breath, blood or urine samples from those exposed. However, these are rarely useful as routine in maritime settings, unless there is immediate access to laboratory support as well as to expertise in the interpretation of results and to knowledge on the ethical aspects of responding to the findings.
E.2.4 Health surveillance
Where the early detection of harm can prevent it becoming more serious, assessment of pre-clinical or early signs of damage can help the seafarer to make personal decisions or receive advice from a health professional on future career options. Equally important is the use of any results from surveillance as evidence on whether there are shortcomings in the risk assessment and risk management. Often information from a group of exposed workers needs to be analysed. Health surveillance, except at its simplest level, such as skin inspections in those working with irritants, is shore-based.
E.2.5 Review of risk assessment and risk management
Reports from supervisors, workers’ concerns, the results of monitoring and health surveillance all need to be reviewed periodically to decide if the precautions in place are adequate. At the same time, suppliers’ information and scientific literature needs to be checked to ensure that there is no new information on the hazard and its risks. If shortcomings in precautions have been detected it may be appropriate to make this information widely available so that others can benefit from it.