Have you ever wondered what actually goes on behind those locked doors at a trial for health and safety offences?
Now is your chance to see who gets blamed for what and why and how they get sentenced – a real eye opener for all of us and something worth seeing or perhaps encouraging your Managing Director to attend.
This is an event which is run by Working Well Together Southwest, a partnership between the Health and Safety Executive (HSE) and a group of construction and safety professionals, including ourselves.
Even better, our MD, Roger Hart, is the person in the dock! So if you’d like to see him sweating under the glare of the lights and the scrutiny of Pinsent Masons please read more and book your place using the link below.
The health and safety team at Pinsent Masons will present a half day mock trial based on a fictional construction based scenario.
This event will follow the legal process of a criminal trial through to the passing of a verdict and will help provide delegates with an idea of what it feels like to “have your day in court”. This is a hugely informative and a must-see event, providing a valuable and sometimes chilling insight into the legal responsibilities of all decision-makers who arrange and carry out construction work, especially Clients and their Contractors.The event is essential viewing for:
Client decision-makers at all levels
Construction Contract managers
Construction Site managers
The charge for the event is £35 WWT Members £45 Non WWT Members BOOK NOW as places are limited.
Event Programme
9.00 – 9.30 Welcome and introduction to the court 9.30 – 12.00 The Trial 12.00 – 12.15 The Verdict 12.15 – 12.30 Discussion on the verdict and questions 12.30 – 13.30 LUNCH
Due to the restricted size of the Guild Hall, places are limited so please book early to avoid disappointment.
Exeter Guild Hall High Street EX4 3EB Exeter United Kingdom
Wednesday, 29 June 2016 from 08:30 to 13:30 (BST)
Contact us on 01453 800 100 if you need expert help with health and safety for a fixed cost or request a call back.
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.
Driving of fork lift trucks (FLTs) on the public highway
This is a question which has been raised by some clients about using fork lift trucks or other materials handling equipment on public roads and highways. Questions have circulated about the need for registration, tax, lights and MOT – read on to find out how you might be affected If you need advice the DVLA can be contacted on 0300 790 6802, please note that we do not provide advice on this issue.
Guidance
Picture of a fork lift truck
Once a vehicle passes onto a public road (or as seen below certain other categories of “road”) further legislation will apply.
The following information has been taken from advice supplied by the Driver and Vehicle Licensing Agency and supporting Guidance V355/1.
The Road Traffic Act 1988 requires that the driver of a motor vehicle when driven on a road must hold the appropriate driving licence, and, if only provisional entitlement is held, to observe the relevant provisional licence conditions.A ‘motor vehicle’ is defined in the 1988 Act as a mechanically propelled vehicle intended or adapted for use on roads. A “road” is defined as any highway, and any other road to which the public has access.
Consequently it would be advisable in our view for an individual to hold the appropriate driving licence entitlement before using any of these vehicles on a “road”.If the fork lift truck is electrically propelled the driver would need a licence covering category L. Alternatively, if the vehicle is exempt from duty, under the Vehicle Excise and Registration Act 1994 because it is used for Agricultural, Horticultural or Forestry purposes (and its road travel does not exceed 1.5km each trip between different areas of land occupied by the same person) a category N licence would suffice. A full category B (motor car) licence gives full cover for both categories L and N.
The Vehicle Excise and Registration Act 1994 provides that any mechanically propelled vehicle used or kept on the public road should be registered, licensed and display registration plates. A fork lift truck can also be licensed within the “works truck” taxation class. The term “Works Truck” means a goods vehicle (that is a vehicle constructed or adapted for use and used for the conveyance of goods or burden of any description) which is designed for use in private premises and used on public roads only;
i) for carrying goods between private premises and a vehicle on a road in the immediate vicinity;
or
ii) passing between one part and another or to other private premises in the immediate vicinity;
or
iii) in connection with road works at or in the immediate vicinity of the site of such works.
‘The immediate vicinity’ is a phrase that has been the subject of much debate and ultimately only the courts can decide what is considered to be the ‘immediate vicinity’. We suggest that travelling any distance on a road as qualifying in respect of registration and road tax. To register a fork lift truck you should contact your nearest Vehicle Registration Office. They will also advise you about the taxation position, depending on the form of propulsion and usage that the vehicle in question is put to.
The driver of a fork lift would not be required to hold a driving licence when driving a vehicle on private land/site to which the public has no access, although the insurers of the vehicle may have their own policy on such matters. We would therefore suggest you contact a reputable insurance company to establish whether they would issue insurance cover to a non-licence holder.”
The “Special Vehicle” tax class encompasses the following vehicles:
Mobile Crane
Mobile Pumps
Digging Machine
Road Roller
Showman’s HGV
Showman’s Haulage Special Trailer
Works Truck – The term “Works Truck” means a goods vehicle (that is a vehicle constructed or adapted for use and used for the conveyance of goods or burden of any description) which is designed for use in private premises and used on public roads only:-i) for carrying goods between private premises and a vehicle on a road in the immediate vicinity; orii) passing between one part and another or to other private premises in the immediate vicinity; oriii) in connection with road works at or in the immediate vicinity of the site of such works.
Vehicles of these descriptions weighing up to 3,500kg pay the PLG rate and tax in the PLG class. Vehicles of these descriptions over 3,500kg pay the basic HGV rate and tax in the Special Vehicles class. If these vehicles are used for purposes outside this concession, the appropriate HGV rate applies.
Exempt Vehicles ‘Limited use’ vehicles, vehicles used by a disabled person, Disabled Passenger Vehicle, Historic vehicles, National Health Service vehicles.
‘Limited Use’ applies to a vehicle used solely in connection with agriculture, horticulture or forestry and its road travel does not exceed 1.5km each trip between different areas of land occupied by the same person.
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.
This is a question which has been raised by some clients following a spate of emails circulating on the web. Read on to find out the opinion of our experienced safety consultants and if you have questions or need more advice please call our safety consultancy on 01453 800100.
Below is a copy of the email (in italics) which started this urban myth;
Email Subject: Drinking Bottled Water Kept in Car
…a friend whose mother recently got diagnosed with breast cancer. The doctor told her women should not drink bottled water that has been left in a car. The doctor said that the heat and the plastic of the bottle have certain chemicals that can lead to breast cancer. So please be careful and do not drink that water bottle that has been left in a car and pass this on to all the women in your life.
This information is the kind we need to know and be aware and just might save us!!!!
*The heats causes toxins from the plastic to leak into the water and they have found these toxins in breast tissue. Use a stainless steel canteen or a glass bottle when you can*!
The first alarm bell which rings here and announces this email as something which may not be 100% true is the fact that all materials containing food stuffs must pass stringent tests before being put into use.
However, there is as usual an element of truth, bottles can potentially leach endocrine disruptors into the water which they contain, in this case man made chemicals which have the potential to interfere with the production of reproductive hormones in the body – not cause cancer.
Research on this subject is in its early stages and there may not be a link – more research is needed but it is a potential concern. Some chemical leaching does take place but these are at levels which are minuscule and do not pose a threat to health. Tests have shown them to always be within the limits set within the EU and US authorities. You’re greatest risk is from microbial contamination, particular in the case of still mineral waters which will not have undergone special treatment to reduce these levels.
The bottom line is that single use water bottles are known to be safe and multiple use water bottles are also safe to the best of current knowledge. Nothing is without risk but you should not be concerned by leaving water bottles in cars but you might not want to drink the warm water anyway – unless you’re very thirsty!
Notes
Some concerns have also been raised involving reusable water bottles and the leaching of bisphenol A (BPA). You may now see a number of baby bottles boasting to be BPA free. This is potentially a concern but research continues into this to establish the actual level of risk and its true effects on the human body.
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.
The benefits to fully, or partially, outsource safety roles to a specialist health & safety consultancy can be substantial. Aside from cost savings, there are other gains your business can make, from outsourcing your health and safety policy development, COSHH risk assessment, SSIP Approvals and even CDM 2015 Principal Designer requirements.
Why should I outsource safety to consultants?
outsource safety will free up your business to focus on its strengths. This will benefit your business by allowing your staff to concentrate on their main tasks and on your future strategy and growth – we will work with your internal health and safety staff to support them and help them improve and develop your health & safety systems;
outsource safety will improve your efficiencyand customer service. When you choose our health & safety consultants to support your internal safety professionals you are gaining the support of a highly experienced and well-connected organisation able to react quickly and flexibly to your business needs;
your business will gain a competitive advantage. Outsourcing your safety will bring flexibility to your business, turning fixed costs into variable costs and freeing up capital. It will also give your business the edge when winning new contracts against your competitors;
We have the skills and experience to support internal your safety professionals on more difficult and diverse risk issues. Areas such as COSHH risk assessments, personal exposure sampling, occupational health assessment and fire require very specific knowledge sets;
Areas which might not affect your business day to day still need to be tackled, for example, an extension which comes under the CDM Regulations will require a CDM support but you do not have the skillset required in house. We have specialists who will work with you and provide a full CDM service
Outsource Safety
It may be tempting to rush into outsourcing, but take the time to meet with one of our health & safety consultants and talk through what you need, we don’t use sales people so the person you meet will be your dedicated contact and retained health & safety consultant.
Consider the following:
Concentrate on your core strengths and not those which are secondary to your success.
Consider the true costs of handling it in-house. Include hidden costs such as office space, training, company cars, recruitment, holidays and so on.
Check the return on investment (ROI) – we can help you to calculate exactly how much you could save whilst getting a better service.
Consider the effects of a temporary downturn – you could have high employment costs when you could be only paying for what you actually need.
What are the costs of not outsourcing? Will your business suffer because it cannot afford to invest in the expertise or the facilities that we can provide? Perhaps your competitors are already outsourcing these roles.
What are the costs of developing new skills sets to cover areas like COSHH risk assessment, CDM Principal Designer duties and Occupational Health requirements?
If you’ve got questions or need support on safety in the industrial, contracting or construction sectors please contact us for sensible and proportionate advice on 01453 800100
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.
Now is your chance to see who gets blamed for what and why and how they get sentenced – a real eye opener for all of us and something worth seeing or perhaps encouraging your Managing Director to attend.
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.
