In a move which we suspected might come to pass some years ago it has been announced that health and safety enforcement may change for smaller businesses.
During July 2016 the HSE ran a consultation on health and safety enforcement allocation. Chiefly, it looked at the role of the local authorities. A range of options were considered, ranging from completely absorbing the LAs’ regulatory powers for health and safety, to allocating them greater duties.
This is something which we discussed on our Breakfast Club sessions for clients and on this blog some years ago. We believe that this is likely to come to pass and the reason will be to bring the lucrative Fee for Intervention (FFI) scheme into play for smaller businesses.
Passing the enforcement role to HSE from overworked EHO’s achieves three goals of the government as we see it;
It eases the burden on councils at a time when their budgets are under stress from central government funding;
It enables the introduction of Fee for Intervention (fee based enforcement) for the remainder of UK workplaces enabling it to reach smaller businesses and drive in additional revenue;
The current situation for sectors such as the motor trade / motor vehicle repair are split untidily between HSE and the LA’s, this change would enable a simpler co-ordinated approach to this type of business which currently falls between HSE and FFI fines and the LA EHO’s and no FFI.
Likely timescales
So, when is this likely to happen? Well, nothing in government moves quickly and so we won’t see any update on the consultation until 2017 with any changes happening in late 2017. However, we do think a change is on the way and HSE are recruiting, watch this space…
Contact us on 01453 800 100 if you need expert help with health and safety for a fixed cost or request a call back.
So, here you are. Steadily driving your way home along a motorway, mile after mile and junction after junction, perhaps in kind of semi aware state casually glancing at the sat nav, speedo or rear view mirror. Every now and then you find yourself simply gazing at the view ahead and seconds turn into minutes and then half an hour passes without you realising it.
Motion induced blindness
It should do because almost everyone that I’ve spoken to has experienced it, particularly on long and familiar journeys with a steady pace and light traffic, the M5 heading past Bristol and into the Southwest is a good example on a weekday afternoon, clear of bank holiday traffic.
The truth is this drifting state is dangerous and its not just when you’re on a motorway.
We often wonder when we come to look at an accident just how it happened. We are given the gift of 20/20 hindsight of course and its always hard to put yourself in that persons position to the extent that you can truly appreciate the thought processes they went through. You are there to try and identify the root causes – that’s why its worth knowing about motion induced blindness as a principle and also raising it with your staff as an issue before these accidents have a chance to occur.
Visual and optical phenomena and safety
So, how do we get this message out there to vehicle fleet drivers, fork lift truck operators, motorcyclists and a whole other raft of people who might benefit? As usual, by training and education – and a very neat graphic courtesy of the internet.
Stare at the central yellow dot and keep looking, do the other three dots then start to disappear? That’s motion induced blindness.
Now imagine yourself at a busy crossroads waiting to pull out with pedestrians and other waiting to cross – can you spot that motorbike approaching?
Or perhaps you’re a a forklift truck driver in a busy warehouse passing by aisles and with pallet movers and pedestrian pickers all around you.
What next?
Use the video above in your training sessions when you have fork lift truck refreshers or new driver training, hold a toolbox talks for those who drive as part of their job (road users or otherwise) or ask us to complete a toolbox talk on your behalf to raise awareness.
How to combat motion induced blindness
You may still be wondering, why the jet fighter image at the top of the page? Fighter pilots are taught a technique to overcome this weakness in the way we process our view of the world around us and its very simple but very effective – you keep you head moving. Don’t believe me? Keep moving your head whilst re-watching the video above and you’ll see the difference – make sure that’s a key part of your training session.
As always, we hope you’ve found the information above interesting and feel you can use it to make a positive change in how you actively manage risk in your workplace.
About: Roger Hart is Managing Director of Outsource Safety Ltd, a consultancy specialising in ISO9001, ISO14001 and OHSAS18001 Management Systems. The company employs 10 staff and works for hundreds of retained clients across the UK in all sectors from Defence and Aerospace to Education and Museums with a specialism in the contracting, construction and renewables sectors, www.outsource-safety.co.uk
Contact us on 01453 800 100 if you need expert help with health and safety for a fixed cost or use our contact us page.
We’ve carried out many monitoring programmes which have involved exposure to styrene vapour over the past 20 or so years. The substance is in common use and because of this businesses and their staff can sometimes become too familiar with the substance and fail to take adequate precautions.
We also have heard staff assuring us that they don’t need to use protective equipment as they have developed a tolerance or even an immunity to styrene’s effects – wouldn’t it be good if that could ever be the case…
In the case below styrene exposure simply wasn’t guarded against and although HSE Inspectors know that small businesses have pressures on them they quite rightly won’t allow this as an excuse to endanger the health of their employees.
If you need occupation health advice, air monitoring for styrene or any other safety support please speak to your retained advisor or contact us on 01453 800100 to get some sound advice.
Solar panel installer falls through fragile asbestos roof, company fined more than £20,000
Templetown Canopies Limited from Tyneside has been prosecuted over the lack of controls regarding the use of the hazardous substance styrene during the production of fibre glass door and window canopies.
Styrene exposure causes irritation to the nose, throat and lungs and neurological effect including difficulty in concentrating, drowsiness, headaches and nausea.
HSE inspected the company premises in May 2013 issued an Improvement Notice. However, the company did not take action to comply with the Notice until they moved premises in March 2015 failing to adequately control exposure of their employees to styrene.
An extraction system should also have been in place to remove the heavier than air vapours and RPE provided with the correct filters (FFP3) to protect operators.
Employees exposed to styrene vapour for almost 2 years
Templetown Canopies Limited, of Shaftsbury Avenue, South Shields, Tyne and Wear, pleaded guilty to breaching Regulation 7(1) of the Control of Substances Hazardous to Health Regulations 2002 (COSHH) and was fined £8,500 and ordered to pay costs of £4,500.
Speaking after the hearing HSE Inspector Fiona McGarry said:
“Workers’ health was put at risk from exposure to styrene for a period of 22 months, even after the company had been made aware of the actions it needed to take.
Whilst HSE is sympathetic to the pressures faced by small businesses, this is simply not acceptable. Employers need to take action to ensure they are providing adequate control to protect the health of their employees.”
With more and more one man bands setting up safety consultancy businesses in the past 10 years its time to question if you’re being given the right advice rather than just advice – there’s a big difference and the outcome can be devastating for individuals and for companiesas this case for a safety advisor being fined.
The case below raises two questions;
Do we know the health risks in our business well enough?
Does our consultant have the right skills for our sector?
Take some time to ask yourself if the person looking after your safety really knows enough about the risks in your business. Perhaps their background isn’t in manufacturing, engineering, construction or whatever it is that you do. If so, get the right advice.
Safety Advisor Fined under HASAWA 1974
Hereford Magistrates’ Court heard how an employee contracted the skin disease after being exposed to sensitising ingredients in rubber compounds.
TRP Polymer Solutions Limited, of Netherwood Road, Rotherwas Industrial Estate in Hereford, has been fined £40,000 after a worker contracted allergic contact dermatitis.
Hereford Magistrates’ Court heard how an employee contracted the skin disease after being exposed to sensitising ingredients in rubber compounds.
An investigation by the Health and Safety Executive (HSE) found the company, which manufactures specialist rubber sealing components and high performance elastomer ‘O’ rings, had failed to assess risks from products used or manage those risks.
TRP Polymer Solutions’ health and safety advisor failed to understand the underlying issues to the level required for the company to understand its responsibilities.
The firm pleaded guilty to breaching Section 2 of the Health and Safety at Work etc Act 1974, and Regulations 6 and 11 of the Control of Substances hazardous to Health 2002, and was fined £40,000 and ordered to pay costs of £6,529.
Paula Underwood, a self-employed health and safety advisor, of Slaughter Castle, Kimbolton, Leominster, Herefordshire, pleaded guilty to breaching Section 3(2) of the Health and Safety at Work etc. Act 1974, for failing to carry out her duty under the act to a level of competence expected by someone carrying out her role, thereby exposing others to risks to their health and safety.
She was fined £1,000 and ordered to pay costs of £200.
Welding fumes from mild steels, zintec (zinc alloys), stainless steels, brass, aluminium and phospor bronze all carry a significant risk of long term health problems if exposure is not properly controlled. As occupational hygienists and qualified safety consultants we have many years experience of carrying out air sampling surveys to determine occupational exposure to welding fumes and similar substances.
Air sampling – Welding of Galvanized (zinc coated) Products
Welding of galvanized steel is completed in a very similar way to welding of the bare steel of the same composition. The same welding processes, volts, amps, travel speed, etc. can be used with little modification when the switch is made from uncoated steel to galvanized steel, unless the zinc coating is unusually thick.The difference between welding galvanized steel and welding uncoated steel is a result of the low vaporization temperature of the zinc coating. Zinc melts at about 480°C and vaporises at about 900°C. Since steel melts at approximately 1,500 °C and the welding arc temperature is 8,300 to 11,000°C, the zinc that is near the weld is vaporised. By the time the weld pool freezes, the zinc is gone giving rise to two immediate consequences:
The vaporized zinc increases the volume of welding smoke and fumes.
The zinc at and near any welds is actually burned off by the heat of the arc, removing the protective zinc coating.
Sometimes a white dust can be seen following welds and this is typically zinc oxide, inhalation should be avoided.
Welding fumes sampling method
A measured volume of air is drawn through a membrane filter mounted in a sampler, and the mass of fume collected is determined by weighing the filter before and after sampling subject to a period of stabilisation. The difference in weight reflects the mass of the fume collected and this, coupled with the flowrate and time period, enable the fume levels to be quoted as milligrams per cubic metre (mg.m-3).
Use of welding fume data for the assessment of exposure
Compliance with Regulation 6 of the COSHH Regulations will be ensured if the occupational exposure standard for particulate welding fume does not exceed 5 mg.m3, provided exposure to other toxic constituents of the fume which have lower occupational exposure limits are adequately controlled. It follows that where the fume contains one or more toxic constituents which have lower occupational exposure limits the OES of 5 mg.m3 may no longer apply.In these circumstances the exposure to individual constituents of the welding fume may have to be quantified separately. This procedure may be simplified for purposes of assessment and, where appropriate, monitoring under the COSHH Regulations. The total weight, in mg.m3, of welding fume at which each of the components of the fume will reach its occupational exposure limit can be calculated from the consumable suppliers’ fume analysis data.
Welding Fumes- Background Information
Welding fume is a varying mixture of airborne gases and fine particles which if inhaled or swallowed may be a health risk. The degree of risk will depend on:
the composition of the fume;
the concentration of the fume; and
the duration of exposure.
The main health effects are:
(a) IRRITATION OF THE RESPIRATORY TRACT
Gases or fine particles of fume can cause dryness of the throat, tickling, coughing, tightness of the chest and difficulty in breathing.
(b) METAL FUME FEVER
Inhaling many freshly formed metallic oxides, such as those of zinc, cadmium, copper etc., may lead to acute flu-like illness termed metal fume fever. With the exception of exposure to cadmium fume serious complications are rare. The most common cause of metal fume fever is welding galvanised steel.
(c) SYSTEMIC POISONING
Systemic poisoning can result from inhaling or swallowing substances contained in welding fumes such as fluorides, hexavalent chromium, lead, barium and cadmium. The presence of these substances in the fume depends upon the welding process being used and the material being welded.
(d) LONG TERM OR CHRONIC EFFECTS
Inhaling welding fumes can lead to benign X-ray changes, referred to as siderosis. A subject of current concern is whether welders have an increased risk of developing respiratory cancer, as certain constituents of some welding fumes, such as hexavalent chromium and nickel, may be carcinogenic.
ORIGIN AND CONSTITUENTS OF FUME
To evaluate the risk to health from exposure, information is required on the sources of welding fume and gases. Usually more than 90% of particulate welding fume arises from the vaporisation of the consumable electrode or rod. The metal being welded usually dictates the welding process and the consumable used, but it does not itself contribute significantly to the particulate fume composition except at certain operations which include:
(a) welding through metallic coatings, e.g. zinc and cadmium plated materials;
(b) welding through painted surfaces such as those which contain lead compounds;
(c) removal of base metal, e.g. cutting or arc gouging.
Depending on the welding process, gases encountered during welding may be:
(a) fuel gases which are used in gas welding and cutting which on combustion will produce carbon dioxide and in some circumstances carbon monoxide;
(b) shielding gases such as argon, helium, carbon dioxide or mixtures of these gases. These gases may be toxic or asphyxiant;
(c) gases produced by the action of heat upon the welding flux or slag, such as carbon dioxide and monoxide;
(d) gases produced by the action of heat or ultraviolet radiation upon the atmosphere surrounding the welding arc. These may include nitric oxide, nitrogen dioxide, and ozone. Ozone may be formed at some distance from the arc, depending upon the welding process being used and the metal being welded.
FACTORS THAT INFLUENCE THE COMPOSITION AND CONCENTRATION OF FUMES AND GASES
The quantity and composition of welding fume and gases are influenced by a number of variables, usually dictated by the job requirements. The most important variable is the type of process: however, it does not necessarily follow that exposure to welding fume will be the same for all welders using a similar process. Therefore each welder should be assessed individually in relation to the job that is being carried out. To ensure an adequate assessment of exposure is made it is necessary to consider each of the factors which are relevant to the particular welding operation..
Gas shielded welding
Gas shielded welding uses a continuous solid wire consumable to provide filler metal and form the arc which is protected by an inert gas shield such as argon or helium (MIG (metal inert gas) welding), or an active gas shield such as carbon dioxide or mixtures of gases containing carbon dioxide or oxygen and an inert gas (MAG (metal active gas) welding). Process variables are important: the arc length increases with the current and the mode of metal transfer changes from globular to spray, with a consequent increase in emission of particles and pollutant gases. Another mode of transfer is obtained by using pulsed current conditions, the fume emission rate will depend upon the welding parameters.
Note: when welding aluminium a change to 98% argon gas can help to create cleaner welds and also reduces the generation of Ozone significantly (a respiratory irritant).
THE EFFECT OF WELDING CONSUMABLE ON CONCENTRATION AND COMPOSITION
The type of consumable used, and its chemical composition, will be dictated by the technical demands of the welding process. Various types are available. MIG consumables may consist of a solid bare wire, or copper coated wire and, in the case of FCW, a tubular wire containing flux in-fill. The type of consumable will affect not only the quantity of particulate fume produced, but also its composition.
An adequate assessment of the risk to health from exposure to welding fume needs information on the chemical constituents and their concentration in the fume. Welding fume will usually contain all the chemical elements present in the consumable, although the proportion and toxic nature will have changed as a result of physical and chemical processes which occur during welding. The most important changes concern consumables that contain chromium, such as those used in hardfacing and welding of stainless steel. Chromium metal in arc welding processes oxidises to trivalent chromium compounds but also some conversion to hexavalent chromium may occur. This is important because trivalent and hexavalent chromium have different occupational exposure limits. Trivalent chromium compounds have an OES of 0.5 mg.m3 whereas the ‘guidance value’ given in Table 4 of Guidance Note EH 40 for hexavalent chromium is ten times lower at 0.05 mg.m3. Where hexavalent chromium is present in welding fume it will therefore be the principal substance of hygiene interest.
Stainless steel MIG welding fume usually contains up to 18% chromium but only a small percentage is likely to be present as hexavalent chromium. An adequate assessment of health risk requires information on the chemical constituents and their concentrations produced from a given consumable during a specified process.
The Welding Manufacturers Association has produced a standard format for hazard data sheets for welding consumables to enable their members to comply with their legal obligations under the Health and Safety at Work etc. Act 1974 Section 6. Most UK manufacturers and suppliers now provide information using this format. The hazard data sheets should include information on chemical analysis of substances of hygiene interest present in the fume produced by the consumable, the appropriate OELs, and an indication of the measures necessary to ensure adequate control.
THE EFFECT OF SURFACE TREATMENT AND PARENT METAL ON COMPOSITION
The composition of the welding consumable is of primary importance in assessment of exposure of welders to fume. In certain circumstances, however, and at specific types of welding operation the surface treatment and composition of the parent metal also need to be considered. Fume from oxygen arc cutting, and flame gouging processes and flame cutting will consist of particulates which are generally similar in composition to the parent metal. Information on the composition of the metal or alloy is important to establish the fume composition and the relevant OEL which will apply. It is likely, although no information is available, that chromium in fume from arc gouging of alloy steels will be present in the hexavalent form and the guidance value of 0.05 mg.m3 for hexavalent chromium will apply.
Surface treatment may include zinc galvanising, cadmium plating or applications of paint primers and sealers. When welding or cutting operations are carried out on coated steels additional constituents of the fume will be formed by the effect of heat on the surface coating. These may include oxides of the metal used for coating, or thermal degradation products from the primer application. Suppliers of coated steels and primer formulations have duties under HSW Act Section 6 to provide information on the composition of the material , the risks and precautions which should be taken during welding. Similarly welding directly on to steel which is coated with oil, to prevent corrosion, can give rise to smoke containing polycyclic aromatic hydrocarbons.
Welding or flame cutting existing steel structures or cutting metal scrap presents particular problems, as the composition of the metal alloy and any surface coating will not be known. Old structures and plant are frequently coated with paint that may contain lead, zinc, chromate or cadmium pigments, which will increase both the quantity and toxicity of the fume emission. Surfaces treated with PVC and/or chlorinated rubber coatings decompose with heat to give fume and gases containing hydrochloric acid and phosgene. In all cases of cutting and welding it is necessary as part of the assessment to determine the composition of any surface treatment, and the metal where appropriate, before work starts, to prevent or control exposure to toxic substances.
Welding certain metals can produce high concentrations of ozone. The predominant pollutant during MIG/MAG welding of aluminium and aluminium alloys is ozone, similarly significant concentrations of ozone are produced during TIG and MIG welding of stainless steel. Ozone is formed by the effect of ultraviolet radiation from the arc on atmospheric oxygen and can be produced some distance from the arc. Effective control of particulate fume emission in certain circumstances can result in significant increase of ozone generation. This is because particulate welding fume may reduce or inhibit emission of UV radiation from the arc.
JOB ASPECTS THAT AFFECT EXPOSURE TO WELDING FUMES
The type of process, size and composition of any consumable used will influence the amount of fume generated and its composition. However, the extent of exposure to welding fume is considerably influenced by the skill of the welder. Changes in current, voltage, welding angle and arc gap can significantly increase or decrease the quantity of fume generated in a given time.
Welding position
The principal welding positions are flat (downhand) horizontal, vertical and overhead. The downhand position is most commonly used and also induces the highest fume levels in the welder’s breathing zone. The welder’s posture in relation to the welding position is also important: exposures of welders in a crouching position are significantly higher than exposures of welders working in a sitting position, and exposure to fume when standing is intermediate between the crouching and sitting position. These differences reflect the proximity of the welder to the welding plume, and every effort should be made to prevent head and shoulder contact with the plume, by changes where practicable to the working position.
Welding location
Equally important is the location of the welding process. In a large workshop and welding on an open structure welding fume and gases will be partially dispersed and diluted by air movement, and although exposure of the welder may be high during arcing the fume and gases do not accumulate in the working area. In a small workroom, or in a space with restricted air movement, fume from welding processes will not disperse so readily, with the resultant increase in average exposure. Work in confined spaces, such as internal welding of process plant or in ship construction, can lead to accumulation of high concentrations of particulate fume, by-product and shield gases, which do not disperse and require the use of efficient ventilation systems to ensure that exposure is adequately controlled and there is no depletion of oxygen of the working atmosphere.
Duration of exposure
Both long term and short term limits relate to the concentration averaged over a specific reference period. For most substances contained in particulate welding fume the averaging period for the occupational exposure limit is eight hours. Exposure to welding fume will be intermittent, the highest exposures occurring during the welding operation, i.e. during arcing or flame cutting. The periods between the actual welding operation should give rise to minimal exposure to fume, although this will depend upon the size of the workshop, the number of welders, their work patterns and effectiveness of control measures and general ventilation. The pattern of work, the arcing time and down time for any individual welder will vary from day to day and similarly duration of exposure and pattern of work will vary significantly between welders although they may be doing similar work. Exposure (to substances hazardous to health) should be calculated according to the approved method, which is reproduced in Appendix 1 of Guidance Note EH 40. Assessment of average exposure becomes very difficult and will require frequent sampling unless the welding operation is of a routine nature, for example production line welding of domestic boilers.
Exposure to solvents such as toluene, xylene or similar substances carries a risk of long term health problems if exposure is not properly controlled. As occupational hygienists and qualified safety consultants we have many years experience of carrying out air sampling surveys to determine occupational exposure to many types of solvent used in paints, glues and mastics amongst other substances.
If you would like to speak to one of our safety consultants or occupational hygienists about an air sampling survey for wood dusts please contact us on 01453 800100. Outsource Safety specialise in Occupational Health and Hygiene consultancy.
Xylene and toluene sampling methods
An activated charcoal badge type dosimeter was used, attached at the lapel. The badge was left exposed for a recorded period and later washed through with a solvent to extract the analyte which is then passed through a gas chromatography instrument to analyse the concentration of particular substances, in this case xylene and toluene were selected.
Xylene – Background Information
OCCUPATIONAL EXPOSURE STANDARDS
8-HOUR TWA: 100 ppm
15-MINUTE REF. PERIOD: 150 ppm
IDENTITY AND PROPERTIES
CAS No: 1330-20-7
EEC No: 601-022-00-9
Formula: C6H4(CH3)2
Synonyms: xylol, dimethylbenzene
Saturated vapour
concentration: about 8000 ppm at 20oC
Boiling point: 137-144 oC
Conversion factor: 1 ppm = 4.34 mg.m-3 at 25oC
Xylene is an aromatic hydrocarbon with a characteristic odour, perceptible at about 1 ppm. Commercial xylene is a mixture of the three xylene isomers and may contain some ethyl benzene. It is a clear, colourless, mobile, fairly volatile fluid, which is insoluble in water and miscible in other organic solvents. Xylene is classified under the CHIP 2 Regulations (1994) as harmful, to be labelled with risk (R) phrases:
R10: FLAMMABLE
R20/21: HARMFUL BY INHALATION AND IN CONTACT WITH SKIN
R38: IRRITATING TO SKIN
OCCURRENCE AND USE
Xylene is produced mainly from crude oil in the UK, but some also arises from coking processes. It is a component of petrol and hydrocarbon solvent mixtures; and is used in chemical manufacture and as a solvent. Individual isomers are raw materials for making terephthalic acid and phthalic anhydride. It is a carrier solvent for surface coatings (e.g. paints, adhesives, pesticides) supplied for commercial and domestic use.
EXPOSURE
Many thousands of workers may be potentially exposed to xylene, with more than 10 000 user-firms in the UK. Typically, exposures to xylene vapours are controlled to below 50 ppm where xylene is used as a chemical precursor and in the manufacture and use of formulated products. Higher exposures may occur in spray-painting large items, printing, and using xylene-containing products in confined spaces; in these circumstances respiratory protective equipment is worn. Short-term exposures up to 500 ppm have been reported in machine-cleaning operations.
MEASUREMENT
Long-term monitoring is performed by pumped sampling with solvent desorption or by diffusive sampling and thermal desorption {Methods for the determination of hazardous substances MDHS 66 (Rev) MIXED HYDROCARBONS (C5 TO C10) IN AIR – LABORATORY METHOD USING POROUS POLYMER DIFFUSION SAMPLERS, THERMAL DESORPTION AND GAS CHROMATOGRAPHY ISBN 0 7176 0867 0 HSE Books (1995)} and gas chromatographic determination. Measurement of the urinary metabolite methyl hippuric acid is a suitable biological indicator of uptake.
METABOLISM
Xylene vapour is rapidly absorbed through the respiratory tract. It is also absorbed by skin contact, and penetrates many materials used for protective clothing. Over 90% of the absorbed dose is metabolised and excreted in the urine as methyl hippuric acid. A small proportion (5%) is exhaled in the breath.
HEALTH EFFECTS
Animal studies
Exposure to high concentrations of xylene has been shown to cause hearing loss and enlargement of kidneys and liver, due to high metabolic demand. Toxicity to reproduction has been observed, but only at or near levels which are maternally toxic. Xylene gave negative results in carcinogenicity and various mutagenicity tests.
Human data
Minimal eye, nose and throat irritation has been reported at levels down to 100 ppm for 30 minutes, and this can also arise with brief exposures at slightly higher levels. The principal effects known in humans are on the central nervous system. Exposure at 300 ppm affected the sense of balance, caused visual disturbances and slowed reaction-times and some effects were seen at 200 ppm; but exposure to 160 ppm over 4 hours caused no significant adverse health effects. At around 700 ppm for up to 1 hour, headache, dizziness and nausea occur. The isomeric composition of xylene is not considered an important factor in its health effects.
BASIS FOR SETTING THE LIMIT
The critical health effects are irritation and central nervous system effects. The irritant effects reported at 100 ppm appear to be minimal and this was considered to be a no-effect level. In view of these irritancy effects an occupational exposure standard was set at 100 ppm (8-hour TWA). Since irritant effects can arise with even brief exposures at higher levels a short-term OES was set at 150 ppm (15-minute reference period). The limits apply to o-, m- or p- isomers of xylene, or mixtures thereof. A ‘Skin’ notation was considered appropriate to indicate the potential for absorption by this route.
Toluene – Background Information
OCCUPATIONAL EXPOSURE STANDARDS
8-HOUR TWA: 50 ppm
15-MINUTE REF. PERIOD: 150 ppm
NOTATION: SKIN
IDENTITY AND PROPERTIES
CAS No: 108-88-3
EEC No: 601-021-00-3
Formula: C6H5CH3
Synonyms: toluol, methyl benzene
Saturated vapour
concentration: about 30 000 ppm at 25oC
Boiling point: 110.6oC
Conversion factor: 1 ppm = 3.75 mg.m-3 at 25oC
Toluene is an aromatic hydrocarbon with the typical sweet/pungent odour of such substances and an odour threshold around 3 ppm. It is a clear, colourless, mobile, volatile liquid which is insoluble in water and miscible with most organic solvents. Toluene is classified under the CHIP 2 Regulations (1994) as highly flammable and harmful, to be labelled with risk (R) phrases:
R11: HIGHLY FLAMMABLE
R20: HARMFUL BY INHALATION
OCCURRENCE AND USE
Toluene occurs naturally in crude oils and is now produced by catalytic reforming of petroleum feedstocks. About 150 000 tonnes per annum are used in the UK. Toluene has widespread use in the production of a range of industrial chemicals, and as a solvent in adhesives, including rubber solutions, coatings and printing inks. It is a common component of many mixed petroleum hydrocarbon solvents.
EXPOSURE
A large number of workers are potentially exposed to toluene. Processes at which exposure to toluene is well-controlled are in the petrochemical sector; exposures are fairly well controlled in the footwear industry (adhesives), silk-screen printing, chemicals production, paint manufacture and decorating industries. In each case mean exposures are less than 15 ppm with more than 96 % of samples less than 100 ppm. Poorly controlled processes include rubber-coating, machine-cleaning, and general adhesives uses, where mean exposures range from 15 to 89 ppm with only around two thirds of samples less than 100 ppm. High short-term exposures can be experienced at liquid transfer points and during manual cleaning. There is a potential for domestic exposure from paint and adhesives.
MEASUREMENT
Short-term measurement can be performed by colorimetric detector tubes, and continuous monitoring is with meters, but these may not be selective for toluene. Long-term measurement is by pumped sampling onto charcoal with solvent desorption, {Methods for the determination of hazardous substances MDHS 36 (Rev) TOLUENE IN AIR – LABORATORY METHOD USING PUMPED CHARCOAL ADSORPTION TUBES, SOLVENT DESORPTION AND GAS CHROMATOGRAPHY ISBN 0 11 885960 9 HSE Books (1990)} or diffusive sampling with thermal or solvent desorption, {Methods for the determination of hazardous substances MDHS 40 (Rev) TOLUENE IN AIR – LABORATORY METHOD USING PUMPED POROUS POLYMER ADSORBENT TUBES, THERMAL DESORPTION AND GAS CHROMATOGRAPHY ISBN 0 11 885961 7 HSE Books (1990)} and gas chromatographic determination. Biological assessment of toluene exposure is by measuring blood-toluene at the shift-end.
METABOLISM
Toluene is readily absorbed by the respiratory tract, and is also absorbed through the skin. It is rapidly distributed, accumulating to some extent in fat and also the liver, brain and lung. Some toluene is exhaled: otherwise it is metabolised to hippuric acid and o-cresol, which are excreted in urine over an extended period.
HEALTH EFFECTS
Animal studies
Inhalation studies showed narcosis at 10 000 ppm, following central nervous system effects. In repeated studies at high exposures, kidney and liver damage occurred, with no effects at 200 ppm. It is difficult to form firm conclusions on findings that exposure to toluene may cause hearing or eyesight impairment.
IN VIVO and IN VITRO studies show toluene is unlikely to be carcinogenic or mutagenic. Toluene only showed teratogenic effects at high doses.
Human data
The principal effects are on the central nervous system with impaired reaction times and vigilance reported for exposures to 200 or 240 ppm for 3 to 7 hours, and dizziness, headache and fatigue reported following exposure at 50 to 100 ppm for 4 to 8 hours. Although longer term effects on the central nervous system have been claimed, there is no substantive evidence that they occur following repeated exposures between 50 and 200 ppm. Toluene vapour is irritating to the eyes and respiratory tract, with no effects being reported at 80 ppm. The liquid irritates the skin. There are no data on carcinogenic effects in humans.
BASIS FOR SETTING THE LIMIT
The critical health effect is upon the central nervous system. A level could be identified which was unlikely to be injurious to employees, and an occupational exposure standard was set at 50 ppm (8-hour TWA) on this basis. However, this implies a need to introduce improvements in control in some industry sectors. A short-term OES was set at 150 ppm (15-minute reference period) which would minimise short-term effects such as irritation. A ‘Skin’ notation was considered appropriate.
We have completed this guidance in response to the recent spate of emails which have raised serious concerns about the levels of benzene which can building up within cars and other vehicles left in hot weather. In common with most of these types of emails there is an element of truth to this statement but what is the true story? Read on to find out.
Starting with the basics, it’s true that benzene is a toxic chemical known to produce a variety of ill health effects, including anaemia and cancer (specifically leukaemia) in humans. Benzene occurs naturally (typically as a component of crude oil) and you’ll also find it used in a range of products as a solvent (plastics, synthetic fibres, dyes, glues, detergents and drugs). It’s also a constituent of tobacco smoke and it present in petrol and petrol exhaust fumes.
Low levels of benzene are often present in outdoor air due to vehicles exhausts and industrial emissions. Vapours containing measurable levels of benzene are emitted by household products such as glues, paints, and furniture wax as products ‘gas off’. Due to this effect even higher levels of benzene can sometimes be found indoors, especially in new buildings with new fixtures and fittings.
Benzene in cars
Given the evidence above we have to conclude that dashboards, door panels, seats, and other interior components do emit benzene, as claimed in the email. In most cars these items will be made from plastics, synthetic fabrics and glues, some of which will have been manufactured using benzene may therefore “off-gas” trace amounts of benzene, particularly under hot conditions.
Scientific research
Most published studies where benzene levels have been measured inside vehicles have been done under typical driving conditions, i.e. in traffic. While such studies have found that benzene levels can significantly exceed those outside the vehicle and could pose a human health hazard, this is mainly attributed to the presence of exhaust fumes from other traffic.
Also, the amounts of benzene actually detected by researchers were significant but were far lower than the amounts that have been stated in these emails. A 2006 study reported in-vehicle benzene levels from exhaust fumes ranging from .013 mg to .56 mg per cubic meter — a far cry from the 400 mg to 4,000 mg reported.
Benzene levels in parked cars
In the one study found that took measurements of benzene levels inside parked cars with their engines turned off, the results were more benign. Toxicologists took samples of the air inside both a new and a used vehicle, under simulated hot-sunlight conditions, measuring the levels of volatile organic compounds (VOCs) including C3- and C4-alkylbenzenes, and exposing human and animal cells to the samples to determine their toxicity. Despite the detectable presence of VOCs (a total of 10.9 mg per cubic meter in the new car and 1.2 mg per cubic meter in the old car), no toxic effects were observed. Apart from noting the slight possibility that allergy-prone individuals might find their condition exacerbated by exposure to such compounds, the study concluded there is “no apparent health hazard of parked motor vehicle indoor air.”
When in doubt, ventilate
Despite this finding, some drivers may still be concerned about the presence of any benzene vapours inside their car, especially given the World Health Organization’s stated position that there is “no safe level of exposure” to the carcinogen. They may also worry that turning on the vehicle’s air conditioner might exacerbate their exposure to trapped toxins by recirculating contaminated air. If that’s the case, there’s no harm done — and much peace of mind to be gained — by simply opening the windows and ventilating the car before turning it on.
We often have questions regarding which mask should be used and so thought a very quick summary here would be useful.
In general, filtering face masks used for dusts and similar can be categorised into three types all with an FFP number.
FFP1 for simple dusts such as nuisance and soft wood dusts
FFP2 for more hazardous dusts such as grinding, powder painting or respirable cystalline silica
FFP3 for hazardous dusts which also involve some vapours and gases which are hazardous to health (a good example here would be welding fumes)
One of the key failing when we review the use of face masks is how people wear them and you should, since November 2002 in fact, be testing the fit of these items to ensure they are effective – this is known as fit testing.
Many people do not fit masks well and do not even press the metal strip fixed around the nose of the mask to get a good seal – if a mask is to protect you this is essential. A second common error is keeping the mask at the point of work uncovered – perhaps on a work bench. This will allow the mask to collect exactly what it should be protecting you from and allow you to inhale it as soon as you use it! Always keep RPE in a sealed container or bag to prevent this type of contamination.
More information is supplied below on the new APF figures. These allow you, once occupational hygienists, such as ourselves, have completed an appropriate air sampling survey, to select an item of RPE which will adequately protect you and your staff from harm (see graphic to the right for more information). The APF is an allowance over which the mask will protect you;
For example; the allowable limit for hard and soft wood dusts is currently 5 mg per cubic metre. In your workplace an occupational hygienist such as one of our safety consultants may measure the dust level at 3 times this amount, 15 mg per m3. In that case you would need to seek an APF (assigned protection factor) of at least 3. This would put you in the typical 4-10 or 4-20 range.
One final point concerns the amount of time which a mask will last before requiring replacement, this can be summarised as follows;
For particulate (dusts) when breathing become more difficult the mask will be partially blocked and should be replaced
For gases and vapours the mask should be replaced when you detect ‘breakthrough’ i.e. when you can detect through smell or taste the item against which you should be protected be that a solvent or other substance.
As a general rule, disposable masks should be disposed of daily and reusable half face respirators should have their filters changed at least monthly.
If you would like to speak to an experienced occupational hygienist about this please contact us on 01453 800100
Exposure to isocyanates such as MDI, TDI or similar substances carries a very serious risk of long term health problems for skin and lungs if exposure is not properly controlled. As occupational hygienists and qualified safety consultants we have many years experience of carrying out air sampling surveys to determine occupational exposure to many types of isocyanate used in paints, glues and foams amongst other substances.
If you would like to speak to one of our safety consultants or occupational hygienists about an air sampling survey for isocyanate exposure please contact us on 01453 800100.
ISOcyanate air sampling method
The methods closely follows the recommendations of HSE MDHS 25/3 and the principle is as follows;
A measured volume of air is drawn through a glass fibre filter impregnated with 1-(2-methoxyphenyl) piperazine mounted in a sampler and attached in the breathing zone of the exposed worker. The Methylene Di-isocyanate (MDI) is held on the filter for subsequent High Pressure Liquid Chromatography (HPLC) analysis using ultraviolet and electrochemical detection. The results of this analysis, coupled with the flow rate and time period, enable the exposure levels to be quoted as milligrams per cubic metre (mg.m-3) for application to the exposure limit published in HSE Document EH40/2001.
ISOCYANATES
all (as -NCO)
MAXIMUM EXPOSURE LIMITS
8-HOUR TWA: 0.02mg.m-3
15-MINUTE REF. PERIOD: 0.07mg.m-3
NOTATION: SENSITISER
IDENTITY AND PROPERTIES
Isocyanate is the functional group (-NCO) which occurs in a number of substances and their reaction mixtures. The saturated vapour concentration at 25oC varies with the substance; refer to manufacturers data sheet.
Conversion factors:
di-isocyanate 1 ppm = 3.44mg.m-3 -NCO at 25oC
isocyanate 1 ppm = 1.72mg.m-3 -NCO at 25oC
Isocyanates react rapidly with all substances having ‘available hydrogen’. This includes alcohols, amines and amide groups in proteins. Isocyanates are soluble in many organic solvents and decompose at varying rates in water. Substances carrying the isocyanate group are not detectable by smell until many times the exposure limit (for example, TDI odour threshold is about 30 times the MEL).
OCCURRENCE AND USE
Organic isocyanates may arise from burning polyurethane. Only MDI is produced in the UK, by reacting methylene dianiline with phosgene in a closed process; other isocyanates are imported. About 60,000 tonnes per annum of isocyanates are used in the UK, of which about half is used for polyurethane foam, and the rest for surface coatings (paints, lacquers, inks, adhesives), foundry core binders and synthetic rubbers.
EXPOSURE
The number of persons who may be occupationally exposed to isocyanate is not known. In general, exposure can be minimised by using isocyanate prepolymers of low volatility. Control measures such as suitable extraction ventilation and use of airline breathing apparatus are needed where isocyanate aerosols or significant vapour concentrations may occur.
Exposures above 0.02 mg.m-3 isocyanate may be experienced in spray-painting large articles, with exposures briefly exceeding 0.06 mg.m-3, Respiratory protective equipment is required for these processes. In most foam plants, exposure is controlled to below 0.01 mg.m-3 isocyanate. Molten MDI can give rise to high exposures if the fume is not extracted.
MEASUREMENT
Methods based on air sampling through bubbler solutions and subsequent instrumental or colorimetric analysis are detailed in MDHS 25.
METABOLISM
The main exposure route is by inhalation of vapour, aerosol mist or dust. Isocyanate reacts rapidly with respiratory tract surfaces; its further metabolic fate is not known.
HEALTH EFFECTS (Human data)
The isocyanate group (-NCO) is the functional group which causes the adverse health effect. Heavy exposure has been associated with bronchitis. There have been numerous reports on asthma due to isocyanates, but the levels which can induce sensitisation are unknown although there are anecdotal reports suggesting that peak exposures may be important. Sensitised individuals may react with severe asthmatic symptoms at very low concentrations of isocyanate, in some cases below 0.02 ppm. The development of sensitisation may occur within months of exposure, or only after years of symptom-free exposure. Sensitisation may result in the development of bronchial hyper-reactivity, and the affected individual responds to non-specific stimuli such as cold air and exercise. In these individuals, recovery may not follow cessation of exposure. Health surveillance is appropriate. {EH 16 ISOCYANATES: TOXIC HAZARDS AND PRECAUTIONS ISBN 0 11 883581 5 HSE Books (1984)}
BASIS FOR SETTING THE LIMIT
The critical health effect of isocyanates is respiratory sensitisation and in the absence of dose-response data a no-adverse-effect level cannot be established. Consequently a maximum exposure limit was considered appropriate. This was set at 0.02 mg.m-3 (8-hour TWA) isocyanate, with a 15-minute reference period MEL set at 0.07 mg.m-3 isocyanate.
You may have noticed these documents floating in on top of a box of items which arrive at your premises or you may be familiar with them from past risk assessments. The truth as to why they’re there is that they’re required by law.
They are the information on which any COSHH risk assessment is based and manufacturers and suppliers are bound by law to make the information contained in them available so that we all have the information needed to decide how best to protect ourselves and others from the substances we use. They’re also useful for comparing a couple of alternative substances and choosing which one is least harmful.
What do I need to know?
One thing which we don’t need to tell you is just how much information is contained in an MSDS – this is where most people say “I must get around to looking at that sometime soon” and nothing much more happens. The truth is that you only need look for some key phrases and in just a few of the 16 sections which make up an MSDS.
Just the facts please!
Think about what questions you need answering;
What are the dangers with using this substance?
What protection do I need to use?
What if an accident occurs, what would my actions be?
What if someone spills this substance, what would I need to do?
It’s all in there…somewhere
Check through the sections, using 1-4 above, this is where you need to look;
Hazards identification – is it corrosive, irritant, harmful?
Exposure controls / personal protection – what PPE do I need to specify?
First aid measures – eye contact, skin contact and so on, its all there.
Handling and storage and disposal considerations – check these two sections for the answers you need.
I think I might give it a go!
Good for you! Bear in mind that your first one will be the hardest. Once you’ve found your feet you’ll be reviewing them in no time.
But what do I do with all this information?
You need to create a COSHH risk assessment. This need not be a lengthy document and it can be simply a part of the risk assessment you complete for a whole task. For example, if you are being exposed to solvent based paints as part of a job which involves painting there’s nothing wrong with completing an assessment which accounts for the whole process – manual handling, fire, sips and trips and so on – COSHH assessment is just a component part. In fact, it might be better way to approach it.
Never mind the quality, feel the width!
Avoid the temptation to bulk out assessments, they won’t be read by the people who use the substance. Keep you risk assessment factual and short.
I could do this but I just don’t have the time and resources
That’s why we’re here! If you need some help over the telephone just call us, there’s no charge. If you would like your consultant to visit and guide you through some of the more difficult ones please let us know as this can also be arranged. Alternatively, if you’d like a specialist from C&G to review everything for you and complete all of your risk assessments for a fixed cost we’d be happy to visit and quote you, just call us on 01453 800100 or visit our contact us page.
Right, I’ve finished. Now what do I do with all these MSDS Sheets?
Keep them on file. Every year or two its good to update them but their most important use is for when you have questions again – this could be when a work process changes. Plus, make sure they’re to hand in case of an accident so you can send a copy with the injured party to inform the medical staff of what exactly has been injected, ingested or inhaled.
Any more questions?
If you have unanswered questions please call one of our safety consultants. We’re here to help on 01453 800100.
In a move which we suspected might come to pass some years ago it has been announced that health and safety enforcement may change for smaller businesses.
businesses in the past 10 years its time to question if you’re being given the right advice rather than just advice – there’s a big difference and the outcome can be devastating for individuals and for companiesas this case for a safety advisor being fined.
Welding fumes from mild steels, zintec (zinc alloys), stainless steels, brass, aluminium and phospor bronze all carry a significant risk of long term health problems if exposure is not properly controlled. As occupational hygienists and qualified safety consultants we have many years experience of carrying out air sampling surveys to determine occupational exposure to welding fumes and similar substances.
