Eliminate The Risks [Jul 2005]
The chemical protection of employees
Eliminate The Risks
The chemical protection of employees
Under the Health and Safety at Work Etc Act 1974 and the Management of Health and Safety at Work Regulations 1999 employers have a legal duty to protect their employees (and anyone else affected) during their work activities.
These Regulations specify that employers should identify and assess the health and safety risks present within their workplace and aim to ideally eliminate these risks from the working environment. Where the risks cannot be eliminated from the workplace, the risks need to be reduced, managed and controlled.
Control measures to reduce risk present within the workplace can vary but often include engineering controls (such as extraction systems), enclosures and guarding. Additional workplace controls can also include procedures i.e. job rotation, strict work instructions and operator information, instruction and training.
Chemical exposures
With regard to chemical exposures, the Control of Substances Hazardous to Health Regulations (COSHH) also applies. These Regulations have been recently updated in 2004 following changes enforced by European directives and concerns expressed by the Health and Safety Commission's Advisory Committee on Toxic Substances (ACTS). Whilst the principal obligation placed upon employers through the COSHH Regulations is to prevent personal exposure to hazardous substances through elimination, substitution or engineering means, many employers provide personal protective equipment (PPE) as the sole means of protection against hazardous substances. The Personal Protective Equipment at Work Regulations 1992 regulates the provision and use of PPE. The main requirement of the PPE at Work Regulations is that PPE be supplied in the working environment where the risks to a person's health (and safety) cannot be controlled through other means. All PPE supplied through a person's work must be free of charge.
Regulation 4 of the PPE Regulations discusses the importance of ensuring the "hierarchy of control" principle has been followed and that the use of PPE should generally be seen as a "last resort". Even so, for many environments it is standard issue as the first line of defence. Some reasons why PPE is the last line of defence are as follows. For the purposes of this article, the PPE discussed will be in the form of chemical protection only.
- PPE (including respiratory protection) is often poorly fitted, with little understanding for the importance of correctly worn equipment
- There is a huge range of PPE available for a plethora of working environments; unfortunately the need to provide specific equipment depending upon the chemical(s) and environment is poorly understood
- Leading from this, many people are put at risk of increased exposure through skin absorption, for example resulting from chemical breakthrough (in gloves especially)
- PPE does have a shelf life, yet many supervisors and operatives are unaware of this and consequently PPE is worn way past its effective 'use by date'
Before PPE is offered for protection against chemical exposures, the employer should undertake a risk assessment of the substances a person may be exposed to, the form it's in (e.g. dust, granule, liquid, mist) and any potential incompatibilities with other equipment or within the working environment. A COSHH assessment will address the risk and identify the PPE required, if any. Since 1995, all PPE provided should be 'CE' marked.
With regard to protecting against chemical exposures, the employer should always look to implement the hierarchy of control. In the practical world, the likelihood of elimination is limited because many processes are designed around particular substances, or generate hazardous bi-products. Substitution can be achieved more easily through simple measures such as changing a powdered product to a granulated material for example.
Yet in reality employers 'deal' with the task in hand as best they can! However, it is clear time and again that employers, managers, supervisors, etc do not have even a basic understanding of the hierarchy of control and consider the issuing of PPE the only means of addressing a problematic area. Without a doubt, PPE has a place in the workplace and regular training is required to ensure it is used to its best advantage. Yet, the fundamental lack of understanding regarding the range of chemicals that can be present at work and the breadth of PPE available to minimise personal exposure renders many to buying either the cheapest or what looks good. Little thought will have been given to why it is needed in the first place and what they are trying to prevent with regard to acute or chronic ill health.
When working with chemicals it is important that the potential for personal contact and exposures are considered. The most obvious route of entry into the body to be controlled is for inhalation and engineering controls, in addition to RPE, aim to reduce the impact of airborne contamination.
Engineering controls
The most important element to any engineering control measure is that they pull the contaminant away from the operator. It is common to see a canopy extractor above a welding bench, or extract fan in the ceiling of a paint mixing room. These forms of extraction, in addition to being ineffective, cause the contaminant to be drawn up past the operators breathing zone instead of pulling away from the operator.
Specific types of engineering control measures have been designed for designated industrial processes. However, depending on the type of process or industry, bespoke units may need to be considered. This can often involve minor adaptations including the addition of a flange to increase the capture zone.
The pictures below were taken from an offshore drilling rig. Powder additives are added to the mud through this hopper. This unit is typical for the offshore environment, as a Venturi system is fitted to the base of the hopper. The side extract duct has been enclosed by a bespoke hood, which does actually greatly improve the extraction capabilities of the unit and feeds into a typical dust extraction system.
If it is not possible to purchase an extraction unit, or develop an existing system, the provision of PPE may be the only suitable alternative to working within a hazardous environment. As has already been mentioned, there is a range of PPE available dependent upon the chemicals or substances a person may be exposed to. PPE supplied to protect against such chemicals is ostensibly looking to prevent or reduce entry into the body via the routes of inhalation (RPE) or skin absorption. As there are various points to be aware of regarding each type of protective equipment, it's probably best to discuss each individually.
Respiratory Protective Equipment (RPE)
Respiratory protection is required to minimise personal exposure to airborne contaminants including gases, vapours, mists and inhalable and respirable particulates, and there are different types of masks and filters to enable this (including combination filters). However, because of the range of protection available, much confusion lies over what protection to provide. In many cases, the wrong type of protection has been provided for either the contaminant, e.g. an organic filter has been provided to protect against an inorganic substance, or the form, e.g. a vapour mask has been provided to protect against a particulate.
Respiratory protection is available in both disposable and non-disposable form. All protection is made to an approved European standard and this is the best way to work out what type of mask one is dealing with (suppliers have internal product codes that will vary depending on the supplier and therefore working out what mask is needed can require some guesswork).
The European codes are universal, so once you become familiar with the basics, understanding what respirator (mask) is what becomes a lot more manageable!
If it has become necessary to provide RPE, it is vitally important that the correct type is used for the environment and that suitable training is given to ensure the correct fitting and maintenance (where necessary) is undertaken. This is because the effectiveness of the equipment may be compromised.
Incorrectly worn RPE in many industries is a common sight because there has been limited or no training in how to fit it. Respirators that can easily be pulled away from the face in order for a quick chat are not correctly fitted! It is a requirement of COSHH that all operatives provided with respiratory protection undergo either qualitative or quantitative face-fit testing. Furthermore, Regulation 7 of the PPE Regulations 1999 discusses the need to ensure that an effective maintenance regime of PPE is established. These should include the responsibilities of employers and employees and where necessary records of tests and examinations undertaken - an area that is typically poorly managed. It is recommended that PPE should be examined by competent persons prior to being issued and used. Such examinations should be undertaken in accordance with manufacturers recommendations and any defects reported.
It should be noted that respiratory protection can put a significant strain on the body, particularly if someone is asthmatic, unfit or overweight. The COSHH Regulations actually specify that those issued with RPE be tested for their fitness to don such equipment, especially if a physical activity is to be undertaken. Positive pressure full-face masks have been known to trigger anxiety attacks in claustrophobic persons, again highlighting the need for information and training.
There are times when respiratory protection is recommended in addition to engineering controls. These often involve activities that use respiratory sensitisers. For example, vehicle paint sprayers typically use an isocyanate based paint, a known respiratory sensitiser. The generation of an aerosol increases the volume of product that could be inhaled and thus air-fed respiration is always used in conjunction with additional engineering controls for this activity. When Lead Chromate paint was used in spraying activities, this too required respiratory protection in addition to engineering controls because of the toxicity of both the lead and hexavalent chromium. Regular tests on the airline is required as well as to the face piece, which is again in accordance with assigned European standards.
Health surveillance in accordance with Regulation 11 of COSHH should be carried out upon operatives who are exposed to known respiratory sensitisers. This is because there is no currently accepted test to assess an individual's potential for sensitisation and so crude analysis of lung function, in addition to other physical assessments, can give an indicator of reduced lung capability, which may suggest the onset of a reaction before the individual is aware of it.
Protection of the skin
PPE available to protect the skin is included within gloves, gauntlets, aprons, chemical suits, overalls, eye and face protection and footwear. Protection for the eyes and face is fairly standard through the use of safety glasses, goggles or visors. These, as with all PPE, are assigned a European standard, typically BSEN166.
For skin protection, as with respiratory protection, it is important that the correct protection is provided for the chemicals to be protected against. All materials will reach what is known as chemical breakthrough after an assigned period of exposure, typically assessed for its capability within an 8hour shift. Chemical breakthrough is where the protective capability of the material has been reached. This can occur after a very short period of time, within 10 minutes for some materials (Xylene against a rubber glove for example) and yet the glove, or other PPE, can still appear visually good and so the operator does not see the need to replace it. Questioning of operators in various industries will highlight that gloves are rarely changed before they visually appear 'used', i.e. fingers have got holes in, the wrist band is no longer tight, etc! Indeed, many operatives would feel that the Stores would 'moan' about having to constantly replace PPE and the procurement department would not be happy at the prospect of rising costs! The only difference there is where operators use the surgical type glove, which only last about 20 minutes anyway and so these tend to be changed more frequently.
As with respiratory protection, it is common to supply a type of glove (or apron) for use against a wide range of chemicals, with little consideration given to the fabric of the PPE, the chemical/substance(s) and the length of time it could provide effective protection. A common example is seen in painting activities. Before paint can be reapplied to an area (pipework for example) it must have the surface prepared to take the paint. This activity is known as 'etching' and is where solvent thinners (typically) are used to remove any grease or other debris. Industrial thinners often contain the solvents Xylene and Toluene. These narcotic solvents are also classified as skin absorbers, with the Sk notation, because they have the ability to be absorbed directly through unbroken skin.
It is not uncommon for operators to use these solvents using either cotton polka-dot gloves, leather riggers gloves, latex surgical gloves holding a rag dipped directly into the solvent and the same gloves will have been worn for days (latex changed after assigned breaks)! The operators usually aren't aware that these gloves are in effect increasing ones exposure to the solvent. This is because the glove material can act as a reservoir with the glove holding residual solvent and it readily being absorbed into the blood stream. Continual application may cause slight reddening on the hand/forearm but the increased body burden would not be considered. Even when more suitable gloves have been used, for example viton, upon questioning the operator may not bother to change the gloves until they visually looked past their 'sell by date', even though chemical breakthrough would have been reached after a matter of hours.
An increasing skin complaint is contact dermatitis, which is suspected to account for 80% of all reported skin complaints. Poor use of PPE such as gloves can increase the risk of developing this complaint or worse, skin sensitisation. It is vitally important that greater consideration is given to the glove material provided for key activities. A properly constructed COSHH assessment should provide the most suitable glove material for the substance/activity.
It should also be noted that the care and maintenance of ones PPE is an important measure to take to increase its longevity. PPE stored with a residue of a contaminant will still degrade whether it is worn or not, further reducing any protective capability for the next time it is worn. Rinsing in water can increase the longevity of some materials by reducing the speed of residual degradation.
The use of disposable overalls has become an increasing popular form of PPE. The impermeable nature of the material has been shown to be beneficial in protecting the skin against a wide range of contaminants. Recent research has shown that some solvent vapours have the ability to cross through unbroken skin, even when impervious overalls are worn. This is because the moisture layer that is formed over the skin as part of natural heat loss, can enable the vapour that has permeated through the overall material to react with the moisture level, convert back into a liquid and cross the skin barrier as other chemicals with the Sk notation. Such new findings should be considered when undertaking risk assessments for working activities, especially where the impact of heat can have an effect on the administrative and other controls.
Unless the reader has a chemical understanding, it may be difficult to interpret whether the constituents of a product contain acid or alkali chemicals (corrosive or irritant), solvent or other hydrocarbon based chemicals (toxic or harmful). These factors will have a bearing on the storage and control measures adopted, including PPE.
To conclude, there are significant controls that can be installed into a workplace to protect operatives from hazardous substances, both through the use of engineering controls and PPE. The most important element is that whatever control measure is utilised it is suitable for the activities and the environment. Engineering controls should be maintained in accordance with COSHH Regulation 9, Maintenance of Control Measures, which involves visual and quantitative assessment. This Regulation also requires the maintenance of RPE, which can be used in conjunction with the PPE Regulations.
Employers can provide suitable PPE for employees to use, but without delivering adequate information, instruction and training in the use of the PPE, the effectiveness and hence protection afforded by the PPE may be compromised. Employees should be made aware of the workplace hazards, the need to utilise suitable PPE and how to correctly wear the protection provided to them. In addition, employees should be aware of actions to take to ensure that PPE is in good working order and in a good state of repair. The extent of the training which is required should of course depend upon the type of PPE being used, the frequency of its use and the individuals who are using the equipment. Refresher training from time to time may also be deemed necessary. Records of all training undertaken should be recorded.
References
COSHH Amendment Regulations 2004
Personal Protective Equipment at Work Regulations 1992
Management of Health & Safety at Work Regulations 1999
Selecting Protective gloves, for work with chemicals, HSE Books, INDG330, 2000
Health risk management: A guide to working with solvents, HSG 188, 1999
Medical aspects of occupational skin disease, HSE MS 24, 1998
In vitro models for prediction of dermal absorption of chemicals, HSE Contract Research report, 178/1998
Occupational Health Statistics Bulletin, 2003/2004
Annals Occupational Hygiene, Vol 48, No 7 583-654
Ceiran Trow, BSc (Hons), LBIOH, principal consultant and Catherine Hare, BSc (Hons), MIOSH, occupational hygiene consultant at Sypol Ltd, one of the UK's leading health, safety & environmental consultancies.
Links to Products and Services
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