Foreword This document has been written as notes to and to augment - - PDF document

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Foreword

This document has been written as notes to and to augment the presentation given by Chris Packham at the Occupational and Environmental Exposure of the Skin to Chemicals conference held at The Pillo Hotel, Ireland, September 2019. Should the reader have comments or questions arising out of these notes or feel that they need additional information the author is happy to hear from them. The document refers to a limited extent to EU/U.K. regulations. However, the general approach to risk assessment is not based on regulations but on the scientific evidence and personal experience of the author.

Introduction

The presentation briefly addressed just some of the practical considerations that affect how we approach the prevention of damage to health due to workplace skin exposure. This is an aspect

• f health and safety where success has so far eluded the health and safety community. As an

example of this, German statistics show that occupational skin disease represents in excess of 30% of all cases of occupational ill health. As the image at the head of this page is intended to indicate, we are dealing with an almost infinite range of working environments, each with its own particular set of conditions. We also have to accept that the way in which our skin interacts with our immediate environment is far more complex than is often appreciated. This is particularly important when considering how chemicals that we encounter in the working environment can affect our health and how we should assess the risk of damage to health occurring. This document attempts to explain some

• f the many factors that we need to consider when attempting to produce a risk assessment

when chemicals are present in the workplace and there is potential for skin exposure. It is important to recognise that this is not a comprehensive, step-by-step guide on how to perform a risk assessment for skin in the workplace. It merely attempts to make the reader aware of the complexity and the need to ensure a structured approach that ensures the risk that results from the assessment reflects the real potential for damage to health and its severity to occur. The aim is to help the reader recognise the complexity and that there are many traps that await the unwary or uninformed. What is a risk assessment? The European Agency for Safety and Health has a very simple definition of what constitutes a risk assessment:

“A risk assessment is nothing more than a careful examination of what, in your work, could cause harm to people, so that you can weigh up whether you have taken enough precautions or should do more to prevent harm.” - Taken from: “Good Practice Information,

provided by EU-OSHA”, September 2009

2 This simple definition does not include an in-depth explanation of the complexities that arise when attempting to assess the risk of damage to health due to exposure to chemicals in the working environment, nor the other elements that form an effective skin management system, such as the action required for effective risk management. The diagram illustrates the elements that the author believes form an effective occupational skin management system.

Risk assessment for skin is task based

What might be described as the ‘traditional’ approach to risk assessment for chemical hazards in a workplace is illustrated in the diagram. The author’s experience is that this is still widely used as an acceptable method of risk assessment for skin exposure to chemicals in the workplace. The procedure is to start by making a list of all those substances associated with the task where the safety data sheets identify them as hazardous, i.e. they have been assigned relevant hazard

• statements. Information on the hazard is also obtained from product packaging labels. Any

exposure to the substances on this list is then identified and from this the risk of damage to health assessed. Unfortunately, as will become clear, where skin exposure is concerned this system is far from

• ideal. It fails on several counts. It does not reflect what happens to chemicals when we use them

and so may not identify the real hazard. A risk assessment on this basis may exclude substances, of which there are many, that, whilst not having been assigned a hazard statement and thus not being shown on the safety data sheet, should skin exposure occur could cause damage to health.

A systematic approach to the skin risk assessment

Our approach to risk assessment should be based on the fact that it is only when we use any substance as part of a task that there is a hazard and this hazard will depend upon the way in which the substance is used. The implications of this will become clear when we consider the hazard as one of the key elements in our risk assessment. What this means, however, is that

• ur risk assessment needs to start with the task under assessment.

3 As the diagram shows, the author’s approach to risk assessment for skin in the working environment starts with the task.

Define task ‘The risk assessment must be specific to the task.’

This is the first step in any risk assessment where chemicals are being used and where skin exposure is concerned. However, if the definition of the task is to be adequate for a valid risk assessment certain conditions must be met. To identify what happens during a task requires at least one visit to the workplace to study what happens during the task under assessment. This will require planning to ensure that the task is actually being carried out at the time of the visit. If the task is one that takes place over an extended time it may not be practicable to watch the whole task. Where the task involves a number of actions where chemicals are used but which may only occur at intervals, so that it is not possible to observe these during the visit then it may be necessary to make repeat visits. Additionally, it may be that there are variations in the task depending on the

• circumstances. Some of which may not be apparent during the visit. Again, repeat

visits may be needed or questions asked of those who will be able to explain these. It may be that occasionally the task has to be modified to meet unusual or one-off

• situations. Such possibilities could affect any risk of damage to health and should

be identified. It is common to find that the person best able to provide this information is the person who actually carries out the task. They should be actively encouraged to partake in the knowledge gathering. Indeed, it is frequently necessary to consider it advisable for there to be a team involved in conducting a risk assessment. There may be a need to engage someone with technical knowledge about the process and the potential effect this may have on the chemicals in use.

Identify all chemicals used - and how used

At the same time as the task is being defined, we should identify all chemicals used. Note the word ‘all’. There are thousands of chemicals that will not appear on a safety data sheet as they will not have been assigned any hazard statements. Alternatively they may appear but have not been assigned any hazard statements relevant for skin exposure.

4 In the fourth edition of his book on patch testing Anton de Groot lists some 4,900 substances identified by dermatologists as skin sensitisers. Only a small percentage of these will have been classified as H317 – may cause an allergic skin reaction. Consider also the situation where the chemical product is a mixture, some

• f the constituents being classified as hazardous, others not. As the latter

will not appear on the safety data sheet but, as will be shown, may present hazards should skin contact occur, relying on the information in the safety data sheet could result in an invalid risk assessment. One of the most common causes of occupational irritant contact dermatitis is water (wet work and wearing of occlusive gloves). Yet one would not expect to see a safety data sheet for water. Indeed, it is not uncommon to find that water is not even regarded as a chemical. Not only do we need to ensure that all chemicals, and their respective hazards, are identified but we need to establish how they are used. In using chemicals, it is almost inevitable that they undergo changes, as the next section will explain. These can result in major alterations in the chemical’s properties and resultant hazards. This is also covered, both in the U.K. Control of Substances Hazardous to Health (COSHH) regulations themselves and in the Approved Code of Practice for COSHH (AC0P). What are we really handling? Among the definitions of what constitutes a substance hazardous to health in the COSHH regulations is the following:

“(e) which, not being a substance falling within sub-paragraphs (a) to (d), because

• f its chemical or toxicological properties and the way it is used or is present at the

workplace creates a risk to health” – COSHH regulation 2(1) – Interpretation

In the sixth edition of the ACoP for COSHH the following statement appears:

“Employers should regard a substance as hazardous to health if it is hazardous in the form in which it may occur in the work activity. A substance hazardous to health need not be just a chemical compound, it can also include mixtures of compounds, micro-organisms

• r natural materials, such as flour, stone or wood dust.”

Neither of these mention the safety data sheet as the source of hazard information. How significant could this be?

Determine the chemical hazards present during the task

We purchase chemicals to use to achieve some outcome. In the process they will almost inevitably undergo some form of change. The table briefly draws attention to some of these.

5 It is beyond the scope of this document to describe in detail how these may affect the hazard and the consequences of any skin exposure. Indeed, there is no simple means of doing this.

“For the time being, there is no EU-wide system in place to assess the combination effects and risks of chemicals.” From ‘Chemicals in our life’, ECHA (European

Chemicals Agency) Of course, in many situations there will be a combination of two or more of these changes. Other factors to consider are: During the task there may be progressive changes in the properties of the chemical. These may not coincide with the moments during the task where skin exposure

• ccurs. So, the times when the hazard is at its greatest may not be the times

where the skin exposure occurs, or the opposite may be the case. In some situations the same chemical may be used repeatedly as the task is repeated. Thus there could be a progressive change in the chemical and the hazard that it

• presents. An example is the solvent degreasing tank. It may be filled initially with

a clean solvent, say toluene. However, once the first article is degreased it is no longer pure toluene. Each time an article is degreased the composition will

• change. Now, if the articles are coming from an external source, for example for

repair or reconditioning, there may be a high level of uncertainty at any one time as to the exact composition of, and hazard represented by, the chemical in the tank. When considering contamination, we may have no information about the contaminants and the hazards that these present. For example, when using a detergent in a scrubber-drier to clean the floor of a shopping mall how will we identify the composition of the soil removed by the cleaning process and present in the waste water tank? Data from suppliers and from other sources Where else may we seek assistance in determining the actual hazard that arises when we use a chemical? Of course, if we purchase a proprietary chemical product, we should have the safety data sheet. However, as has been explained, this can be a very unreliable source of data as it only deals with the product as supplied, and then may not provide a complete list of constituents. However, in the U.K. there is an additional source that is often overlooked, namely in this case the

• supplier. Experience indicates that many will not be aware that the U.K. Health and Safety at

Work etc. Act 1974 includes the provision of information not required for the actual safety data

• sheet. Section 6(4) of the Act states:

It shall be the duty of any person who designs, manufactures, imports or supplies any substance for use at work: (c) to take such steps as are necessary to secure that there will be available in connection with the use of the substance at work adequate information about the results of any relevant tests which have been carried out on or in connection with the substance and about any conditions necessary to ensure that it will be safe and without risks to health when properly used.

At least one prosecution has occurred in the U.K. of a supplier who did not conform to this

• requirement. So, when considering the hazard, it could be helpful to remind suppliers of their

responsibilities other than just the production of a safety data sheet. One implication of this is that there is a case for a much higher level of information exchange between supplier and user. Under the EU’s Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) Regulation this requirement is supported by the stipulation that the organisation that has registered the chemical product provides with the safety data sheet what are termed Exposure Scenarios detailing how the product can be used safely for the purposes for which it was

• registered. However, since these cannot match every possible variation that will be found in the

real world they tend to be somewhat generic in nature, and may not be relevant for a specific task.

6 Experience indicates that where the chemical product is being supplied by a distributor they may well lack the ability to provide this information and one may need to refer back up the supply chain to the manufacturer or the body responsible for the original registration under

• REACH. In the EU some additional information is available from the website of the body

responsible for REACH, the European Chemicals Agency in Helsinki, but again this tends to be generic and may not match what is really happening during the task under assessment.

Identify exposure

Let us assume that we are confident that we have correctly identified the real hazard that presents itself during the task. The next step is to identify and assess the nature and extent of any actual, or potential, exposure. Here again, matters are not quite as simple as many assume. Consider the following statement:

“However, there is no scientific method of measuring the results of the body’s exposure to risk through dermal contact. Consequently, no dermal exposure standards have been set.” - from “Occupational skin diseases and dermal exposure in

the European Union (EU-25): policy and practice overview - European Agency for Safety and Health at Work

In the U.K. the sole guidance for employers seeking to ensure regulatory compliance is that skin exposure to chemical hazards should represent best practice. However, there is no clear definition of what this is. This presents the employer with a problem. Given that there is no clear standard how will they demonstrate compliance? Measuring skin exposure The question therefore often arises about how we can measure skin exposure so as to be able to quantify the risk of damage to health and demonstrate that appropriate action has been taken to manage the exposure to a regulatory standard. The answer is that measurement of skin exposure is seldom a practicable proposition. Given that there are no dermal exposure standards, what would be the purpose of skin exposure measurement in a risk assessment? We may be able to state that our measurement indicated x μg/cm2, but what would this mean, particularly since it would only be a single measurement

• n one individual area of skin and the response of the skin to contact with a chemical can vary

by a factor of 40 depending upon where the contact occurs? Furthermore, different workers completing the same task may have differing work practices and practical experience shows that this can significantly vary the level of exposure that each will experience. In addition, the question we need to resolve is: ‘What are we going to measure?’ What lands on the skin

It can be argued that this is the actual exposure. However, it’s significance for the risk of damage to health may vary.

What stays on the skin

Corrosive or irritant chemicals can cause direct damage to the cells in the surface layer of the skin. However, a validated means of quantifying such damage does not yet exist, particularly given the variations that will exist between individuals and between different areas of skin on the body.

What is absorbed into the skin

Chemicals absorbed into the skin can cause changes in the living cells. These may activate the immune system resulting in allergic reactions

What penetrates the skin

Chemicals penetrating the skin may reach internal

• rgans resulting in systemic toxic reactions

Of course, we may be faced with combinations of these. Furthermore, the effect will vary depending on other factors, such as individual susceptibility, location on the body, ambient conditions and skin barrier condition as a result of other exposures, both occupational and non-

• ccupational.

7

Is it just skin exposure?

There are three main routes of exposure to chemicals, these being inhalation, ingestion and dermal (skin). Traditionally the approach has generally been to consider these as separate, discrete routes and to deal with the risk assessment and exposure management of each

• individually. Yet there is abundant evidence that this is not the case and that each route can

have consequences that one would normally associate with exposure via one of the other routes. The diagram shows the links between each. If we consider allergic skin reactions, the most common

• ccupational type is what is

termed a type IV immune response, usually referred to as allergic contact dermatitis. This

• ccurs

when a person has developed sensitisation, a condition where the immune system will over- react to contact via the skin with a molecule

• f

a chemical known as a sensitiser. Once sensitisation has

• ccurred any subsequent skin contact may result in the release of chemicals that initiate the

familiar rash, blistering and itching sensation. Dermatologists, however, have a separate category of allergic skin reaction that they call ‘systemic contact dermatitis’. This has been defined as a type IV allergic skin reaction caused by exposure by a route other than the skin. Both inhalation and ingestion can cause systemic contact dermatitis. One of the most common causes of skin allergies is due to exposure to nickel. It is not uncommon to find those allergic to nickel developing the skin reaction when their diet is changed, and the result is an increase of nickel from the food they consume.

This case illustrates the type of interaction that one can encounter. The case report described a patient who had developed a skin reaction resembling psoriasis. Treatment with two different oral steroids did not clear the skin problem. Further investigation revealed that some years before he had been diagnosed with allergic contact dermatitis to thiurams, chemicals that are commonly found in natural rubber and nitrile gloves and that are well known to cause an allergic skin reaction. However, he was not wearing gloves at the time of the later skin problem. So, was this allergy relevant to his present problem? The answer was ‘yes’, but in an unexpected way. It was discovered that he was being treated for alcoholism, the treatment being a prescription drug called Antabuse, taken

• rally. It so happens that Antabuse is a thiuram. The reason that the regular oral treatment

with a steroid was unsuccessful was because it was being countered by the oral intake of thiuram!

Of course, it can work the other way. There is considerable evidence that skin uptake of isocyanate can elicit an asthmatic reaction in someone already sensitised to this chemical. Isocyanate exposure can occur in a number of occupations, particularly in the manufacture of polyurethane foam and in two component materials such as two pack paints and epoxy resins. When paint spraying using two component paint containing isocyanate occurs in a workplace it is common to find that great attention is paid to ensuring adequate respiratory protection with the provision of air fed hoods. Skin protection is often dealt with by the provision of single- use nitrile gloves. This ignores the fact that the hardener usually contains a solvent, commonly

• xylene. Whilst the respiratory protection may be perfectly satisfactory in preventing inhalation
• f this solvent, permeation through the single-use gloves will occur very quickly, probably in

less than one minute! Not only will this be undetectable by the wearer, but the xylene will have

8 dissolved the isocyanate and will have enabled this also to permeate through the gloves to reach the skin. The employer is left wondering why the paint sprayer is developing asthma and trying to establish what is wrong with the respiratory protection when this is not the route of exposure! Systemic toxicity There are many chemicals that, if they can reach the target organ or system within the body, can cause damage to harm. Some may, on their own, be able to penetrate the skin. Others may not, but when used for a task become dissolved in a liquid, e.g. a solvent. That can act as a vehicle and take the toxic chemical through. There are studies that show that in many situations skin uptake exceeds respiratory uptake. It’s the total dose that counts! We should not lose sight of the fact that for the target organ or system it is the total dose reaching it that is the key factor that will determine whether and to what extent a systemic toxic effect will occur. Thus, when assessing the risk of damage to health, whilst we may find that the uptake by each of the three routes of exposure may not be sufficient individually to raise concern, the total uptake could well be significant and require action. Here biological monitoring can be a valuable tool. The skin as an organ Our skin is an active organ and, as such, can be affected by what is happening within the body as well as what it is being exposed to in its immediate environment. Thus, when encountering situations where adverse skin effects appear to indicate occupational exposure, we should not lose sight of the possibility of endogenous conditions that may result in a skin condition that mimics a contact dermatitis or contact urticaria. The New Zealand dermatology network (www.dermnetnz.org) website contains a list of over 100 constitutional health conditions that can do this. The 24:8 rule A further factor to consider is that we have our skin for twenty-four hours each day, of which less than half will be spent in the working environment. Indeed, if we consider week-ends and holidays, it is surprising how much of our working life is spent away from the workplace. Not

• nly can we find many chemicals present in the non-occupational environment that are

hazardous to the skin, but it is unlikely that the way in which they are being used will have been subjected to a risk assessment. We also have no control over how these are used. The same chemical may also be present in the workplace and at home or used in a hobby. Irritant skin damage Statistics indicate that the most common form of occupational skin disease is contact dermatitis and that the greater part of this will either be due to irritant damage to the skin, or that irritant damage will have played a major role. If we consider chronic irritant contact dermatitis it is normally due to an accumulation of damage as a result of repeated exposures to many different irritants, some

• f which will occur away

from the working environment. The diagram shows how damage due to skin contact with irritant chemicals (a) can accumulate (due to repeated exposure to

9 different irritants at the sub-clinical level (b). Initially this accumulation of damage remains undetectable by visual or tactile examination of the skin. Eventually the point may be reached (the ‘threshold’) where the damage becomes visible (c), i.e. we have what is technically a clinical contact dermatitis situation. Once this has happened it is important that action is taken to eliminate, or reduce, any skin exposure to irritant chemicals. If appropriate action is taken the skin will recover to the extent that it reverts to a normal

• appearance. However, it is still vulnerable and too early a reintroduction to irritants can quickly

result in a return of the irritant contact dermatitis. Given the variety of irritants and the potential for exposure to be both workplace and non-occupational manging irritant contact dermatitis can be extremely difficult. An additional complication arises as at a subclinical level the damage results in reactions within the skin that can predispose to sensitisation and allergy. Thus identifying any irritant damage at the earliest possible stage is particularly important. Detecting sub-clinical damage from skin contact with irritants There are techniques for detecting the asymptomatic damage due to skin contact with irritants, the most common being skin hydration measurement. It is known that as the irritant damage increases, and whilst still at an asymptomatic level, residual skin hydration levels fall, so measuring skin hydration can achieve early detection (whilst the damage is still invisible to the eye) and permit effective intervention. How might this affect the risk assessment So now, instead of simply considering each individual route in isolation it becomes necessary when carrying out a risk assessment to include the possible combinations of routes. As yet, little research appears to have been done on how we risk assess chemical exposure when more than one route of exposure is possible. Certainly, simply assuming that because our airborne exposure is below the regulatory exposure limit (WEL, TLV, MAK, etc.) all is in order as far as airborne exposure is concerned may no longer be valid. Indeed, in this connection there is evidence that airborne dermal exposure at a level below the exposure limit may still be sufficient to result in an adverse health effect.

“Air threshold limits are insufficient to prevent adverse health effects in the case of contact with substances with a high dermal absorption potential.” - Drexler H, Skin protection and

percutaneous absorption of chemical hazards, Int. Arch Occup. Environ. Health (2003) 76:359- 361

“Direct transdermal uptake from air is not routinely considered. Yet the studies outlined in the previous paragraph suggest that, for at least some indoor pollutants, direct dermal uptake from air may occur at rates that are comparable to or larger than inhalation uptake.” – Weschler CJ, Nazarofi WW, Dermal Uptake of Organic Vapors Commonly Found in

Indoor Air, Environmental Science & Technology, 2014, 48, 1230-1237

One possible approach is to utilise what is termed biological monitoring. If one route of exposure is to cause an adverse health effect that would normally be associated with a different route of exposure this will almost inevitably involve transmission with the body. Monitoring the level of uptake in the body should be capable of identifying this. Biological monitoring involves techniques to detect and quantify the presence of a chemical in breath, blood or urine. This detects the total present by all three routes of uptake. This should present no real problem for the risk assessment since it is the total dose that is the significant

• factor. Should this be unacceptably high, action can then be initiated to establish the

contribution being made by each of the three routes.

Assess the risk and severity of damage to health

The reality is that there is no simple, easily applied means of quantifying exposure, nor is it always easy to determine what the effect of any exposure could be. However, we need to apply some simple means of deciding whether what we have in place is acceptable or whether we need to take further action to ensure that what we are doing does not cause damage to health due to skin exposure. In order to be able to assess the consequences of any skin contact with the chemical it is essential to have at least a basic knowledge of how the skin interacts with its immediate environment and the consequences. Again, as the diagram shows, this is not as simple as many assume.

10 In the first place the skin is not simply an outer, inert membrane but an active organ with many roles that are essential for our wellbeing. So, what is happening inside our body can have a considerable impact on what happens as a result

• f skin exposure in the workplace.

A common condition, known as ‘atopy’, a genetic condition, can render an individual particularly sensitive to contact with one or more chemicals at levels that would not affect others. Stress can affect the skin’s ability to resist damage from

• chemicals. And it need not be skin exposure. There is abundant evidence that there can be

interaction between skin and exposure due to inhalation and ingestion. We also should not lose sight of the fact that we have our skin for twenty-four hours every day but only spend some of that time at work. Our skin can well be exposed to chemicals capable

• f causing skin disease away from work as well as at work. Since irritant contact dermatitis is

generally the result of repeated exposures to many different irritants and since there is no practicable means of determining the relative significance of the different exposures the situation may be somewhat confused. Now add to this that much occupational skin disease will be chronic in nature. In other words, unlike falling off a ladder, the consequences of inadequate control of exposure may not appear for some considerable time, possibly many years and it should be clear that risk assessment for chemical exposure – not just for the skin – is more complex and uncertain. What is clear is that…

We lack practical tools for the non-expert in the workplace to enable them to conduct effective risk assessments for chemical exposure.

Who should be involved?

All of this indicates that in many situations defining the task may require more than one person, not just the one tasked with the risk assessment but the actual operator, possibly someone with appropriate engineering knowledge to understand the implications of what is involved in the task, someone with toxicity and industrial chemistry knowledge to be able to identify the real hazards due to the changes that occur in the chemicals during the task and potentially someone with appropriate biophysical knowledge who can interpret the data obtained by the others with regard to human exposure to be able to determine the potential for damage to health to occur, particularly where the exposure may be as a result of exposure by more than one route. In simple terms, in many situations risk assessment will need to be a team effort.

What now?

Bear in mind that in the majority of workplaces, particularly the smaller ones, the person with the responsibility to conduct a risk assessment where chemicals are present and being used will almost certainly not possess the specialised training, knowledge and experience nor time available to be able to complete a complex, sophisticated assessment involving complex measurements and calculations.

I be I belie lieve tha that the t the c chal alle leng nge f for r tho those i in n occ ccupa upatio tiona nal l hygie giene a and nd

• cc

ccupa upatio tiona nal l he heal alth is th is to w to work k to togeth ther r to to dev develop s p suc uch h a s syste stem.

11 Chris Packham Dermatological Engineer August 2019 EnviroDerm Services Hedworth, Grange Court, Westbury-on-Severn, GL14 1PL, U.K. +44 (0)1386 832 311 - chris@enviroderm.co.uk