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| NIOSH Home > Safety and Health Topics >Skin Exposures and Effects >Occupational & Environmental Exposures of Skin to Chemicals- 2005> Abstracts |
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Controlling Dermal Exposure to Chemical HazardsC. Packham, Enviroderm Services, Evesham, UK Methods
The aim of this document is to review the problems and questions that arise when attempting to identify, assess and appropriately manage dermal exposure in a workplace. The hope is that the scientific, medical and technological communities will be stimulated to develop equipment and techniques that can be applied to resolve these gaps in our knowledge and methodology so as to enable us to create and maintain workplaces that are healthy and safe, at least as far as dermal exposure is concerned. The techniques should be such that they can be applied by both the larger organisations with qualified health and hygiene specialists and the smaller enterprise where such knowledge will not be readily available on a day to day basis. The content of this document is based on the presentation on this topic given by the author at the Occupational and Environmental Exposure of the Skin to Chemicals Conference in Stockholm in June, 2005. When do we need to manage dermal exposure?
In any working environment it is inevitable that there will be situations where workers are exposed to chemical, physical and biological hazards. The question is then whether we need to manage such exposure. It is obvious that total avoidance of all such exposures is impracticable, whether at work or away from the workplace. Attempting to manage all exposures would quickly result in a workplace which simply could not function or where productivity or costs would be so adversely affected as to render continuation of the operation impossible. Thus we need to reach a decision as to the point at which we decide that exposure to a particular chemical or group of chemicals is such that reduction is needed. Is zero exposure the aim?
We might assume that if there is no exposure, then there is no risk of damage to health. However, this principle cannot be applied equally to all chemical hazards. True there are some where any exposure may be life threatening. Equally, there will be many where some degree of exposure is not only of no threat, but positively beneficial. As an example, we use water to wash other, more hazardous, chemicals from our skin, which, itself, needs a certain water content to function correctly. However, excessive exposure to water will have an irritant effect on the skin that may eventually result in irritant contact dermatitis. This can even be applied to physical agents. We need a certain level of exposure to UV radiation (sunlight) to stimulate the synthesis of chemicals in the skin that generate much of the Vitamin D3 that we need to stay healthy. We even use UVA in the treatment of skin diseases, such as psoriasis. On the other hand, exposure to UV can result in premature skin ageing and an increased risk of skin cancers. It is obvious, therefore, that we need to find a balance, i.e. not so much exposure that a significant risk of damage to health exists, but sufficient to avoid unwanted negative effects. The problem arises in determining exactly what this is. Do we have enough data?
For the majority of employers, particularly those with small or medium sized enterprises, the main source of data on the hazards of chemicals that are present in their workplace will be the Safety Data Sheet (SDS) provided by the supplier of the product in question. Unfortunately, SDS frequently fall far short of adequate in this respect. A whole range of studies have shown that as many as 50% of SDS may either be incomplete or contain significant errors or inaccuracies. Furthermore, SDS tend to be regarded by suppliers as providing information for supply, i.e. to be relevant for their product as it is delivered to the customer. This is not necessarily relevant or sufficient for the customer to identify the hazards that arise when the product is actually used. Use may result in changes that also change the hazard. A product may be mixed with another with the mixture presenting completely different properties to those of the original chemicals. Particularly in small and medium sized enterprises (SMEs) the knowledge may not be present to identify these changed hazards. In several countries suppliers have interpreted the regulations to mean that they only need to provide information on those chemicals that have risk (R) phrases and then only when the concentration is above a specified level. Unfortunately, there are many chemicals capable of causing irritant damage to the skin that do not have a risk phrase, since the level of irritation that is caused is relatively minor and chronic. However, repeated exposure, particularly when this is to several different irritants, can result in cumulative damage to the skin that will, in time, cause an irritant contact dermatitis. It is just these chemicals where we often find repeated and extended exposure in many workplaces. Since the employer will have no data on these, indeed may not even have been informed of their presence in the product he is using, he is unlikely to include them in any risk assessment. It is clear that there is a need to review the information provided to the employer and possibly to change the requirements in the SDS to reflect the data required for an accurate understanding of the hazard of the product as used, particularly when this may involve changes due to the process, mixing etc. This information must also be made available in a format that is comprehensible to the employer, who will rarely have had much training in occupational health and safety. This leads to the next question: Who is responsible?
The view is often encountered among those responsible for the management of an organisation that the responsibility for health and safety is the remit of the health and safety team. In fact, this is rarely the case. In most countries, legally the responsibility is ultimately with the person who controls the overall way in which the organisation operates, generally the Chief Executive Officer. In practice, however, the CEO can usually only set the policy. It is those who control how the day to day activities of the organisation are managed and operated, i.e. the departmental or ‘line’ managers, who are responsible for a particular workplace area or operation. Since it is they who decide how a particular activity will be conducted, and what methods and chemicals will be used, it is they who will have the greatest influence as to what standards of control and hence levels of exposure will occur. The health and safety team or specialist can usually only operate in a support role, providing advice and guidance where needed and to conduct audits to identify whether standards are being maintained at an appropriate level. Thus our attention should be directed at ensuring that these managers:
In this we need to remember certain key factors that will dictate how we approach this requirement.
Any system that we devise or expect them to implement must reflect these factors. To expect them to carry out the type of work that would be done by an industrial hygienist or health and safety inspector, for example taking exposure measurements, conducting biological monitoring, etc. is simply not realistic. Emphasis must be on: Education and training A simple system that can provide sufficient information to enable dermal exposure risks to be assessed adequately and, where appropriate, specialist advice from the health and safety team or specialist sought to deal with a situation beyond the manager’s competency. Senior management should ensure that these managers are also adequately supported as part of the organisation’s general policy on health and safety. In this they must also accept that the risk assessment and risk management work will take a certain amount of time and will need to ensure that work load for the manager allows for this. What confounding factors do we need to consider?
In assessing the level of exposure to a chemical or chemicals that is acceptable a number of problems arise. Firstly we need to recognise that there are significant differences between individuals. Indeed, the variation in reaction between individuals is one factor that makes it so difficult to develop dermal occupational exposure limits. What will not affect the majority may well affect a small group of people. Secondly, we need also to recognise that, particularly with substances that may penetrate the skin and cause systemic damage, we are not dealing with an inert membrane, but with a living, almost infinitely variable organ, the performance of which will vary depending upon many influences. There is abundant evidence showing that differences in skin condition will result in different reactions to chemical exposure. So where the nature of the work may have an adverse effect on the skin of the worker we may need to set lower exposure levels than where the skin is not so affected. Different workers will carry out a task differently, even where there is a standard procedure. Thus whilst one worker may manage to limit his exposure to a chemical to a level where it is unlikely to present a risk to health, another may be excessively exposed. Almost invariably in a real workplace we will be working with mixtures, the hazards of which may be quite different from that of the individual constituents. Operations such as the application of heat may change the hazard. This will need to be reflected in our risk assessment. Changes in ambient conditions will also need to be reflected. Studies have shown, for example, that warm, humid conditions can increase the penetration of chemicals through the skin. A worker who is sweating may well react differently to a chemical that otherwise would cause no damage to the skin. How do we develop a strategy for risk management?
The fact is that the variety of factors that influence the risk to health from dermal exposure is so great that we simply do not yet know enough to set realistic workplace dermal exposure limits. Furthermore, the measurement of dermal exposure is also complex and not something that we can expect the average manager to carry out. However, some risk assessment is better than no risk assessment. So can we provide the manager with simple tools that will help him to ensure that his workers do not come to harm? In the first place we need to ensure that there is adequate data available. Although there is a great deal of data from studies etc. this is not usually easily accessible to the average manager, nor would he or she find it comprehensible. So there is a case for some form of publicly accessible database that can collect, compile and interpret such data so that the average manager can know what hazards he or she is facing in their workplace. How such a database could be developed and financed is a matter for debate. We need a simple system that allows a manager with limited time and knowledge of health and safety to conduct a simple risk assessment to establish whether the operation is safe or whether he or she needs specialist advice or support. We then also need guidance on simple, cost-effective control methods that the manger can implement to manage any such risks. Action now!
As specialist consultants concerned with the prevention of damage to health from workplace dermal exposure we know that simple risk assessments are possible and that simple methods can often be introduced that control the exposure at source. Personal protective equipment, such as gloves, should be reserved for back-up protection where the technical control methods do not achieve adequate control. Most of the technical control methods do not require extensive investment and can often produce a reduction in operating costs, over and above the savings from reduction in cases of ill health. So whilst we need to continue to develop our understanding of the science and biology surrounding the skin and its interaction with the working environment, we also need to take action now. People at work are being harmed now. It is in our power to eliminate much of this. We would be failing in our responsibility to society if we were not to act now.
Content last modified: 12 July 2005 |
