The technical basis for COSHH essentials: Easy steps to control chemicals

The technical basis for COSHH essentials: Easy steps to control chemicals Introduction This report summarises the technical basis of the generic risk assessment scheme used in the Health and Safety s (HSE s) guide COSHH essentials: Easy steps to control chemicals. It replaces the priced publication The technical basis for COSHH essentials (ISBN 978 0 776 8) and partly replaces publication HSG9. It complements and updates the articles published,, in the Annals of Occupational Hygiene. Part is aimed at occupational hygienists and other specialists who want to: understand more of the background and technical issues; know how to apply COSHH essentials when there is more information about the toxicological hazard than is given by the R-phrase (CHIP 5 classification) or the H-statement (CLP-GHS 6 classification); know how to use COSHH essentials in less common situations; or extend it to cover additional tasks or process-generated hazards. This report describes the basis for the generic risk assessment to identify a Control Approach, appropriate to control the risk. It explains the technical basis of the scheme and provides information when additional toxicological information is available. It does not cover validation of the scheme or its development, which the papers by Brooke and Maidment cover in some detail. The information here helps those with more specialist knowledge to adapt the scheme or develop guidance specific to their processes. A subgroup of HSE s Advisory Committee on Toxic Substances (ACTS) developed the risk assessment scheme. 5 Part explains the routines used in the Internet version of COSHH essentials (www.coshh-essentials.org.uk) and its application to some common situations. 6 The Control of Substances Hazardous to Health (COSHH) Regulations 00 (as amended) 7 provide the main legislation in Great Britain to protect against health risks arising from hazardous substances used at work. Under COSHH, employers have a duty to carry out a suitable and sufficient risk assessment, and take steps to ensure exposure is prevented or adequately controlled. There is a detailed Approved Code of Practice. 8 7 However, extensive market research showed that many small and mediumsized enterprises (SMEs) have difficulty with this approach. 9 Responses to HSE s consultation document on small firms showed that SMEs want basic, readily available advice that sets out what they need to do. of 5 pages

8 COSHH essentials meets this need for many chemicals and products. It has two aspects: simple generic risk assessment producing advice on good control practice for common operations control guidance sheets ; control guidance sheets for certain industry-specific tasks or processes. 9 COSHH essentials has the status of guidance. Control guidance sheets are written in a straightforward style, for use by employers and others in SMEs who are unlikely to have skills in chemical risk assessment. COSHH essentials guidance is intended to inform but not to constrain occupational hygiene professionals. Part : A generic risk assessment scheme 0 The scheme provides a practical route for selecting an appropriate Control Approach: general ventilation; engineering control local exhaust ventilation, eg dust or vapour extraction; containment. For some common operations (eg mixing, filling, weighing), the scheme indicates appropriate control guidance sheets that contain basic descriptions of control equipment and good practice. Table Generic (G) control guidance sheets Unit Operation Title No. Solid Liquid General tasks General ventilation G00 Y Y Storage General storage G0 Y Y Open bulk storage G0 Y Dust extraction Removing waste from dust extraction unit G0 Y General tasks Local exhaust ventilation G00 Y Y Fume cupboard G0 Y Y Laminar flow booth G0 Y Y Ventilated workbench G0 Y Y Dust extraction Removing waste from dust extraction unit G0 Y Transfer Conveyor transfer G05 Y Sack filling G06 Y Sack filling G07 Y Sack emptying G08 Y Filling kegs G09 Y Charging reactors/mixers from a sack or keg G0 Y IBC filling and emptying G Y Drum filling G Y Drum emptying (drum pump) G Y Weighing Weighing G Y Mixing Mixing G5 Y Mixing G6 Y Mixing G7 Y of 5 pages

Unit Operation Title No. Solid Liquid Sieving Sieving G8 Y Screening Screening G9 Y Surface coating Spray painting G0 Y Spray painting G Y Powder coating G Y Lamination Batch lamination G Y Continuous lamination G Y Dipping Pickling bath G5 Y Pickling bath G6 Y Vapour degreasing bath G7 Y Drying Tray drying oven G8 Y Y Continuous drying labyrinth oven G9 Y Pelletising Pelletising G0 Y Tablet press G Y General tasks Containment G00 Y Y Glove box G0 Y Y Dust extraction Removing waste from dust extraction unit G0 Y Transfer Transferring solids G0 Y Sack emptying G0 Y Drum filling G05 Y Drum emptying G06 Y IBC filling and emptying G07 Y IBC filling and emptying G08 Y Tanker filling and emptying G09 Y Tanker filling and emptying G0 Y Filling kegs G Y Transferring liquid by pump G Y Packet filling G Y Bottle filling G Y Weighing Weighing G5 Y Weighing G6 Y Mixing Mixing G7 Y Mixing G8 Y Surface coating Robot spray booth G9 Y Automated powder coating G0 Y Dipping Vapour degreasing bath G Y Drying Spray drying G Y Y Special General principles G00 Health surveillance for occupational asthma G0 Skin or eye contact General advice Selection of personal protective equipment S00 S0 Appendix contains an index to guide the selection of control guidance sheets. Table lists new sheets, some of which should be available as automaticallyselected downloads from the COSHH essentials web tool. of 5 pages

Table New guidance sheets for skin and eye contact; respiratory protective equipment (RPE); and generic special advice Topic Title No. Skin and eye Skin or eye contact Selecting protective gloves Selecting personal protective equipment (PPE) Skin or eye contact RPE UK Standard Assigned Protection Factor (APF) R UK Standard Assigned Protection Factor 0 (APF0) UK Standard Assigned Protection Factor 0 (APF0) UK Standard Assigned Protection Factor 0 (APF0) Breathing apparatus with UK Standard Assigned Protection Factor 0 UK Standard Assigned Protection Factor 000 (APF000) S00 S0 S0 S00 Special Health monitoring for chronic obstructive pulmonary disease G0 Health surveillance for occupational dermatitis Health surveillance exposed to respirable crystalline silica (RCS) New and existing engineering control systems Urine sampling for isocyanate exposure measurement Exposure measurement air sampling R R R R5 R6 G0 G0 G06 G08 G09 Generic risk assessment takes account of the chemical s or product s health hazard, and the exposure potential. The health hazard is represented by the R-phrases assigned to substances during classification by suppliers under CHIP 5 or the CLP-GHS. 6 The exposure potential is represented by physical properties of the substances (dustiness for solids, volatility for liquids) and the amount used in an operation or batch process. Figure Factors used in risk assessment to identify appropriate control measures HEALTH HAZARD Substance allocated to a Hazard Group using R-phrase or H-statement + EXPOSURE POTENTIAL Substance allocated to a dustiness or volatility band and a band for the scale of use GENERIC RISK ASSESSMENT Combine health hazard with exposure potential factors to determine the degree of control needed CONTROL APPROACH Approach needed for adequate control 5 Note: this generic risk assessment applies to liquids and solids only: it does not apply to gases or to liquids used above their boiling point. 6 The generic risk assessment scheme (which is not intended for use as an exposure model): defines adequate control for different hazards in exposure ranges; identifies exposure ranges associated with Control Approaches for different situations; and considers ways to link these. of 5 pages

7 The four steps involved in the scheme s development are covered in paragraphs 8 to 6: Step : Group the hazards that have adequate control at similar airborne concentrations. Step : Group the physical properties with amounts used that show similar potentials for exposure. Step : Assess the anticipated exposure from each Control Approach, for each combination of physical property and amount. Step : Link Step with Step, to form the generic risk assessment scheme. Step : Grouping hazards Notes to Table Units parts per million (ppm), and milligrams per cubic metre (mg/m ). R-phrase combinations, eg R0// means R0, R, R and combinations thereof. Examples of other combinations include R/. Modifiers R9/, R8/ and R68/ change the emphasis of the subsequent R-numbers. 8 Hazards were allocated to one of five groups, A to E, by the R-phrases given in CHIP, and in the H-statements in the CLP-GHS by analogy. Table gives the ranges assigned to each group and the associated R-phrases or H-statements. Brooke s paper states the rationale for this grouping. Appendix lists the R-phrases and H-statements used in COSHH essentials. 9 Groups A, B, C and D cover a logarithmic concentration range for dusts and vapours. The upper boundary for Group A represents levels that should not be exceeded regularly, in accordance with good control practice: 500 parts per million (ppm) for vapours and 0 mg/m (milligrams per cubic metre) for dusts. 0 Hazards (R or H) were assigned to one of the Groups A to D where an airborne concentration range could be identified as providing adequate control. Where no such airborne range could be identified, eg for serious health effects such as cancer, the hazard was assigned to Group E. Table Allocation of R-phrase or GHS phrase to Hazard Group; concentration range Hazard Group A Type Concentration range Units R-phrases H-statements R6, R8 and all R-numbers Vapour >50 to 500 ppm not otherwise listed H0, H0, H05, H, H5, H6, H8, H9, H0, H, H6 and all H-numbers not otherwise listed B C D E Dust >0. to mg/m R0// and Vapour >5 to 50 ppm R68/0// Dust >0.0 to 0. mg/m R//5, R, R5, R7, R9///5, R, R, Vapour >0.5 to 5 ppm R8/0//, R68///5 Dust <0.0 mg/m R6/7/8, R9/6/7/8, R0, R8///5, R60, Vapour <0.5 ppm R6, R6, R6, R6 Dust - mg/m R, R5, R6, Vapour - ppm R9, R68 H0, H, H, H7 H0, H, H, H7, H8, H, H5, H70, H7 H00, H0, H0, H5, H60, H6, H6, H7 H, H0, H, H50 5 of 5 pages

Hazard Group S skin and eye exposure Group S was triggered by risk-phrase numbers R, R, R7, R, R5, R7, R8, R, R, and R, R or R7 in combination with R9, R8 or R68. However, since most substances and products can irritate or penetrate the skin, there is nearly always a skin risk. Step : Grouping physical properties and amounts The determinants of exposure in COSHH essentials are physical property and amount in use. The physical property for solids is a subjective assessment of the material s dustiness. Simple descriptors of dustiness put a substance into a high, medium or low dustiness band. The physical property for liquids is volatility at the process temperature. A chart relating boiling point to process temperature allocates a substance into a high, medium or low volatility band. 5 The other determinant is the amount in use for the task. Table describes these determinants. Table Exposure potential Solid Liquid Determinant Dustiness Volatility Low Medium High Pellet - does not break up Granular or crystalline Fine solid and light powder Boiling point of liquid ºC 00 50 00 50 00 50 Low volatility Medium volatility Operating temperature ºC High volatility 5 0 50 75 00 5 50 Determinant Amount Amount Small Grams Millilitres Medium Kilograms Litres Large Tonnes Cubic metres 6 The ACTS subgroup used professional judgement to allocate combinations of physical property and amount into one of four Exposure Predictor Bands. These EP bands are shown in Table 5. 6 of 5 pages

Table 5 Definitions of Exposure Predictor Bands from amount and exposure potential Low dustiness Medium dustiness High dustiness Exposure Predictor Band Grams Grams EP Solid Kilograms and tonnes Grams EP Solid Kilograms Kilograms EP Solid Tonnes Tonnes EP Solid Low volatility Medium volatility High volatility Exposure Predictor Band Millilitres EP Liquid Litres and cubic metres Millilitres Millilitres EP Liquid Litres and cubic metres Litres Cubic metres EP Liquid EP Liquid Note: Table 7 associates these EP bands with exposure bands 7 A third factor, duration of exposure, influences exposure potential. This was not included in the generic risk assessment scheme. However, COSHH essentials contains a filter for activity with a total time below 5 minutes per day. An explanation for Time is in Part, in the Cut-off values section. Step : Predicting exposures using Control Approaches 8 There are four basic Control Approaches used in COSHH essentials generic risk assessment. Table 6 Four Control Approaches Control Approach Type General ventilation Engineering control Relative efficacy General description A good standard of general ventilation and good working practices. 0-fold reduction Containment 00-fold reduction Local exhaust ventilation ranging from well-positioned capturing and receiving hoods to effective partial enclosing hoods. Full enclosures and containment, where small-scale breaches may be expected. Special - Expert advice is required to select appropriate control measures. Note: The efficacy estimate is, in many cases, precautionary and relative to general ventilation (=). 9 The ACTS subgroup applied professional judgement to determine, for each Exposure Predictor Band EP to (solid or liquid) in Table 5, the exposure levels that would result from applying Control Approach, or in Table 6. 7 of 5 pages

0 Table 7 presents the outcome of ACTS judgement. Table 7 Relating Exposure Predictor Bands to Control Approach Predicted exposures for dust in air, milligrams per cubic metre (mg/m ) Exposure Predictor Band Control Approach Control Approach Control Approach EP Solid 0.0 to 0. 0.00 to 0.0 <0.00 EP Solid 0. to 0.0 to 0. 0.00 to 0.0 EP Solid to 0 0. to 0.0 to 0. EP Solid >0 to 0 0. to Predicted exposures for vapour in air, parts per million (ppm) Exposure Predictor Band Control Approach Control Approach Control Approach EP Liquid <5 <0.5 <0.05 EP Liquid 5 to 50 0.5 to 5 0.05 to 0.5 EP Liquid 50 to 500 5 to 50 0.5 to 5 EP Liquid >500 5 to 500 0.5 to 5 Step : Linking the hazard s acceptable exposure with predicted exposure The final step to complete the risk assessment scheme is to relate the target airborne exposure range for each Hazard Group (Table ) to the Exposure Predictor Bands (Table 7). Box Method For a given Exposure Predictor Band: Does general ventilation (Control Approach ) give exposures within or below the Hazard Group concentration range (Table )? If so, CA is appropriate: otherwise it is not. Does engineering control (Control Approach ) give exposures within or below the Hazard Group concentration range? If so, CA is appropriate: otherwise it is not. A similar analysis applies for Control Approach. If none of these approaches is able to give sufficiently low exposures, specialist advice is recommended (Control Approach ). 8 of 5 pages

Table 8 shows the allocation of hazard bands to Table 7. Table 8 Relating Exposure Predictor Bands and Control Approach to Hazard Group Predicted exposure ranges for dust in air, milligrams per cubic metre (mg/m ) Exposure Predictor Band Control Approach Control Approach Control Approach Control Approach EP Solid 0.0 to 0. 0.00 to 0.0 <0.00 Hazard Groups A, B, C D - - EP Solid 0. to 0.0 to 0. 0.00 to 0.0 Hazard Groups A, B C D - EP Solid to 0 0. to 0.0 to 0. Hazard Groups A B C D EP Solid >0 to 0 0. to Hazard Groups - A B C, D Predicted exposure ranges for vapour in air, parts per million (ppm) Exposure Predictor Band Control Approach Control Approach Control Approach Control Approach EP Liquid <5 <0.5 <0.05 Hazard Groups A, B, C D - - EP Liquid 5 to 50 0.5 to 5 0.05 to 0.5 Hazard Groups A, B C D - EP Liquid 50 to 500 5 to 50 0.5 to 5 Hazard Groups A B C D EP Liquid >500 5 to 500 0.5 to 5 Hazard Groups - A, B C D These predictions were validated and refined either by comparison with published exposure data, or where this has not been available, by extensive peer review. Maidment s paper provides further information on the development and validation of Steps and. Independent validation of some general ventilation and engineering control scenarios was undertaken based on BAuA data. 0 Validation of containment scenarios continues. 9 of 5 pages

Box Example: a solid in Hazard Group B Hazard Group B: target exposure range = 0. to mg/m of dust. Gram quantities EP, low/medium dusty solid g 0.0 to 0. mg/m with general ventilation Below target range of 0. to mg/m : CA is adequate. EP, high dusty solid g 0. to mg/m with general ventilation Within target range of 0. to mg/m : CA is adequate. Kilogram quantities EP, medium dusty material g to 0 mg/m with general ventilation Outside target range of 0. to mg/m with CA. With CA g 0. to mg/m is within target range. CA is adequate. Tonne quantities EP, medium dusty material g >0 mg/m with general ventilation Outside target range of 0. to mg/m with CA. Outside target range of 0. to mg/m with CA ( to 0 mg/m ). With CA g 0. to mg/m is within target range. CA is adequate. Table 9 rearranges the information in Table 8 to relate the Hazard Group directly to the Control Approach. The exposure ranges are unnecessary information. Table 9 Control Approaches (CAs) needed for each Hazard Group Hazard Group and phase Exposure Predictor Band EP EP EP EP A solid CA CA CA CA A liquid CA CA CA * CA B solid CA CA CA CA B liquid CA CA CA CA C solid CA CA CA CA C liquid CA CA CA CA D solid CA CA CA CA D liquid CA CA CA CA E solid CA CA CA CA E liquid CA CA CA CA Note: * CA for EP, Hazard Group A liquid. Subsequent validation tests found that largescale use of medium-volatility liquid required Control Approach. 5 Table 9 was refigured and published as reproduced in Appendix, part of HSG9 (ISBN 0 776 77 ). Figure re-expresses this table. 0 of 5 pages

Health and Safety Figure LIQUID: Volatility M Hazard Group D H L Hazard Group A M L H H L Hazard Group C M L H M Hazard Group B SOLID: Dustiness Hazard Group E ALL to : Control Approach L: Low, M: Medium, H: High M Hazard Group D H L Hazard Group A M L H H L Hazard Group C M L H M Hazard Group B Inner circle: Small amounts Middle circle: Medium amounts Outer circle: Large amounts 6 There are three differences between Table 9 and Figure : As noted in the footnote to Table 9, a medium amount of high-volatility liquid in Hazard Group A takes Control Approach. A precautionary difference compared with Table 9, a large amount of highvolatility liquid in Hazard Group B takes Control Approach rather than. A precautionary difference compared with Table 9, a large amount of mediumvolatility liquid in Hazard Group C takes Control Approach rather than. of 5 pages

Further information on how to use COSHH essentials 7 COSHH essentials provides simple control advice for many commonly occurring situations, using information from Part 5 of the safety data sheet. The system makes no attempt to cover every possible exposure scenario, or explain just how to use additional toxicological information. In any case, REACH safety data sheets should stipulate risk management measures for exposure scenarios, so COSHH essentials, in its generic form, is likely to fall into disuse over the next decade. 8 The schemes in COSHH essentials can be used for other purposes, for example: to compare substances and help in making decisions on substitution; to suggest the degree of control required of a control system. 9 This section provides further information for the more specialist user. Toxicological information 0 Only some CHIP classification criteria take account of potency. Potency is the strength of a substance s ability to cause a specified health effect. Examples where potency is part of classification are for single or repeated exposure effects, such as R0 to R8, R and R5, the R8 combinations. Classification criteria that do not involve consideration of potency include respiratory tract irritation (R7), respiratory sensitisation (R) and skin sensitisation (R). The classification is based simply on a committee s yes/no decision. For carcinogens and substances toxic to reproduction, classification is based on strength of evidence that does not take potency into account. R-phrases that do not involve consideration of potency (which may vary considerably) were assigned to Hazard Groups on the basis of: the seriousness of the health effect; and whether an exposure range could be identified to represent adequate control. Consequently, the ACTS group allocated each of these R-phrases in such Hazard Groups as they considered would not lead to health risks, even if exposure were at the upper end of the range for the most potent substance with that R-phrase. The subgroup felt strongly that this precautionary approach was appropriate for a generic risk assessment scheme. Where it was impossible to identify an exposure range representing adequate control for an R-phrase, it was allocated to Hazard Group E. This meant that the substance so classified required individual and expert consideration. 5 When an expert has access to toxicological information, eg the dose-response relationship, for an effect of a particular substance with no potency delimiter, COSHH essentials allows allocation to another Hazard Group. (See Reduction of Hazard Group section.) This is usually a lower Hazard Group, for example a substance assigned R7 (respiratory tract irritation) from Group C to Group B, or R60-R6 (effects on reproduction) from Group D to Group C. 6 Substances assigned R5, R6 and R9 (Group E) are subject to the Carcinogens Approved Code of Practice 8 and must not be assigned to another group. Other R-phrases in Group E are associated with serious health effects: allocation to another group is not recommended. of 5 pages

7 For substances for which the lead health effect is skin sensitisation (R), allocation to a lower group may be appropriate if there is evidence to show that sensitisation is unlikely to result from contact with the airborne substance. However, any substance labelled R is a candidate for health surveillance (skin). Part : Routines for mixtures within the Internet version of COSHH essentials 8 The routines for mixtures in COSHH essentials are: If any component is in Hazard Group S, then the mixture is Hazard Group S. If any component is in Hazard Group E, then the mixture is Hazard Group E. If any component is in Hazard Group D at >= 0.05% then the mixture is Hazard Group D. If any component is in Hazard Group C at >= 0.5% then the mixture is Hazard Group C. If any component has a classification R then see subsidiary R rules (below). If any component is in Hazard Group B at >= 0% then the mixture is Hazard Group B. Otherwise the mixture is Hazard Group A. Subsidiary R rules for mixtures 9 Where any component of the mixture has R at or above 0.% but less than 0.5%, classing the mixture as Hazard Group C results in an over-precautionary Control Approach. The volatility or dustiness should relate to the major component of the mixture (Hazard Group A or B). The following matrix replaces the lookup table on page 5 of HSG9 for substances in Hazard Groups A and B that contain 0.% to less than 0.5% of an R component. Table 0 R mixture rules Amount Small Low dustiness/ volatility Medium volatility Medium dustiness High dustiness/ volatility Substance with >= 0.% to <0.5% of a component with R and no other mixture component giving Hazard Group C or D CA CA CA CA Medium Large CA CA CA CA CA CA CA CA Note: CA, CA and CA are Control Approaches. The option for stipulating water as a mixture ingredient is not implemented (water, by default, is Hazard Group A). However for mixtures of solid in water, the volatility may be assumed as low rather than medium (ie boiling point >50 C, not 00 C). of 5 pages

Summary of the rules, conversion factors and default values in COSHH essentials Hazard Grouping The Hazard Group according to the CHIP R-phrases is as set out in Appendix, with the exception of R9 in combination with 0, or, which is rarely used. Reduction of Hazard Group based on specific toxicological information R-phrases R, R5 and R7 The R-phrases R or R5 (corrosive) normally require Hazard Group C because of concerns for respiratory tract irritation. R-phrase R7 (respiratory tract irritancy) normally falls into Hazard Group C. The expert can consider allocating substances with these R-phrases to Hazard Group B when there are no other R-phrases that require the substance to be assigned to Hazard Group C, D or E, and when: respiratory tract irritation has been quantitatively studied in humans in goodquality investigations and there is clear evidence from these studies that the threshold concentration for respiratory tract irritancy is > 0. mg/m for dusts or > 5 ppm for vapours. The expert can consider allocating them to Hazard Group A when there are no other R-phrases that require the substance to be assigned to Hazard Group B, C, D or E, and when: respiratory tract irritation has been quantitatively studied in humans in goodquality investigations and there is clear evidence from these studies that the threshold concentration for respiratory tract irritancy is > mg/m for dusts or > 50 ppm for vapours. R-phrases R6 and R6 The R-phrase R6 (Category, impaired fertility) normally falls into Hazard Group D. The expert can consider allocating a substance with R6 into Hazard Group C when there are no other R-phrases that require the substance to be assigned to Hazard Group D or E, and when: the lowest observed adverse effect level (LOAEL) for reproductive toxicity, obtained from good-quality animal studies, is > 5 mg/kg/day oral; or > 0 mg/ kg/day dermal; or 0.05 mg/l/6hr day inhalation. The expert can consider allocating to Hazard Group B when there are no other R-phrases that require the substance to be assigned to Hazard Group C, D or E, and when: the lowest observed adverse effect level (LOAEL) for reproductive toxicity, obtained from good-quality animal studies, is > 50 mg/kg/day oral; or > 00 mg/ kg/day dermal; or 0.5 mg/l/6hr day inhalation. The R-phrase R6 (Category, harm to unborn child) normally falls into Hazard Group D. The expert can consider allocating to Hazard Group C when there are no other R-phrases that require the substance to be assigned to Hazard Group D or E, and when: the lowest observed adverse effect level (LOAEL) for developmental toxicity, obtained from good-quality animal studies, is > 5 mg/kg/day oral; or > 0 mg/ kg/day dermal; or 0.05 mg/l/6hr day inhalation. of 5 pages

The expert can consider allocating to Hazard Group B when there are no other risk phrases that require the substance to be assigned to Hazard Group C, D or E, and when: the lowest observed effect level (LOAEL), for developmental toxicity, obtained from good-quality animal studies, is > 50 mg/kg/day oral; or > 00 mg/kg/day dermal; or 0.5 mg/l/6hr day inhalation. Conversion factors Temperatures Celsius to Kelvin: ºK = ºC + 7. Room temperature (default) is taken as 5ºC. For activities at room temperature, low volatility means a boiling point above 50ºC, medium volatility a boiling point between 50ºC and 50ºC, and high volatility a boiling point at or below 50ºC. There is no conversion from Fahrenheit to Celsius, ºC = 5/9 x (ºF ). Where heating or cooling is applied, for process temperature (PT) the volatility band is determined as follows: If boiling point <= x PT + 0, then volatility = high. If boiling point between x PT + 0 and 5 x PT + 50, then volatility = medium. If boiling point >= 5 x PT + 50, then volatility = low. Pressures atmosphere = 760 mm mercury (mm Hg) or 760 torr = 0.5 kpa = 05 Pa (Pascals) = 0.98 Bar = 980 mbar The values used in COSHH essentials to allocate high, medium and low volatility are given in Table. Table Volatility and vapour pressures Volatility band Low Medium High Vapour pressure Less than 500 Pa 500 to 5 000 Pa More than 5 000 Pa Calculation of vapour pressure at one temperature for data quoted at another temperature This calculation combines the Clausius-Clapeyron equation with the Trouton Rule, as described in Horvath A L (Molecular design, Elsevier 99 p.85). It is an approximation that is acceptable given the precautionary nature of COSHH essentials. L n P atm = -0.6 x (T bp / T ) where L n is the natural logarithm, P is in atmospheres, and T bp (boiling point) and T (temperature of the process) are in Kelvin. The quoted value for the vapour pressure at a specified temperature is used to calculate a notional boiling point. Substituting this value in the equation with the temperature at which you use the substance will produce the vapour pressure at that temperature. 5 of 5 pages

Cut-off values Temperature and pressure A lower temperature cut-off for boiling point = 0ºC. A cut-off for vapour pressure was set at atmosphere. Such substances will be in the vapour phase at room temperature (a gas), and COSHH essentials cannot currently deal with gases. Frequency and duration of use (time-weighting) A threshold of 5 minutes use per day was built in to the electronic COSHH essentials, below which the Control Approach drops from (containment) to (engineering control), or from to (general ventilation). The superficial reason for this is that COSHH essentials is task-based and precautionary. The HSC Advisory Committee on Toxic Substances judged that the level of control needed for (undefined) short-term activity did not hold the same degree of reasonable practicability as the level of control for prolonged use. The hypothesis underlying COSHH essentials is that an increase in Control Approach ( to, or to ) affords at least a 0-fold increase in protection from dusts and vapours. Were you to exceed an 8-hour limit value ten-fold over 0 minutes, with no further exposure, that would equate to the limit value over 00 minutes, ie less than 8 hours. New rules for producing guidance on exposure on or via the skin Control Approach S00 Control Approach S00 + S0 + S0 Control Approach maintenance S00 + S0 + S0 Control Approach S00 + S0 + S0 Where R classification appears G0 New rules for producing guidance on RPE Table is taken from Respiratory protective equipment at work. Table Selection of an RPE standard with COSHH essentials input data Hazard Group A B C D E Amount Dustiness or volatility Low Medium High Small - - - Medium - APF = APF = 0 Large APF = APF = 0 APF = 0 Small - APF = APF = Medium - APF = 0 APF = 0 Large APF = 0 APF = 0 APF = 0 Small - APF = APF = Medium APF = 0 APF = 0 APF = 0 Large APF = 0 APF = 0 APF = 0 Small APF = 0 APF = 0 APF = 0 Medium APF = 0 APF = 0 APF = 0 Large APF = 0 APF = 0 APF = 000 Small APF = 0 APF = 0 APF = 0 Medium APF = 0 APF = 0 APF = 0 Large APF = 0 APF = 0 APF = 000 Note: Assigned protection factors are based on those in BS 75. 6 of 5 pages

New rules for producing other guidance Control Approach and G06 (LEV care) All Control Approaches G09 (air sampling) Less common situations and COSHH essentials The following paragraphs give advice for: solutions (dissolved substance); aerosol generation; volatile solids. Solutions of a solid in a liquid COSHH essentials produces different controls for dusts and vapours. It cannot deal with both at once. The most common situation is mixing a solid and liquid. The controls are considered separately for transfer into the mixing container. Once in a liquid, dustiness is not relevant. So in the assessment: Treat solids dissolved or dispersed in water as liquid with low volatility (despite water having a boiling point that normally causes it to be medium volatility ). Treat solids dissolved or dispersed in a solvent as solid-in-liquid. Take the volatility as that of the main solvent. Where a substance is classified R, retain this classification unless there is less than 0.% of that substance in the solvent. Aerosol formation and generation Where a task is likely to generate an aerosol, there is a significant increase in the exposure potential. It can be difficult to estimate the amount of aerosol, so it is precautionary to consider the amount as the total amount of substance in use. Aerosols form in: spraying and printing; electroplating with gas generation; hot vapour condensation (fume); dispersal through contact with fast-moving machinery; decompression, such as a pre-packaged hand-held aerosol spray product. Specific control guidance sheets are available for some aerosol-generating tasks (Appendix ). Otherwise, the precautionary principle is advised: to adopt a more stringent control approach than indicated by COSHH essentials. COSHH essentials was never designed to assess gases. For hand-held aerosol sprays, the propellant is considered as a gas by COSHH essentials and the assessment halts. The solution is to ignore the propellant, to take the boiling point as that of the lowest boiling ingredient in the product, and the amount as small or, if several cans are used (as in artwork), medium. Volatile solids Few solids have an appreciable vapour pressure (eg iodine, benzoquinone, paraformaldehyde, naphthalene). For such substances, their dustiness may not 7 of 5 pages

show their full exposure potential: it may also be necessary to consider volatility. The safety data sheet or supplier should give information on volatility. For such substances, compare the Control Approaches for the solid and for the vapour. The more stringent Control Approach takes precedence. The vapour pressure bands in Table apply. However, it is unlikely that many solids have volatility above 0.5 kpa (9 ppm) at room temperature. 8 of 5 pages

Appendix : Index to generic series Control Guidance Sheets Control Approach General Ventilation Unit Operation Sheet title Solids Liquids Small Medium Large Small Medium Large General tasks General ventilation G00 G00 G00 G00 G00 G00 Storage General storage G0 G0 G0 G0 G0 G0 Open bulk storage G0 Dust extraction Removing waste from dust extraction unit G0 G0 G0 Control Approach Engineering Control Unit Operation Sheet title Solids Liquids Small Medium Large Small Medium Large General tasks Local exhaust ventilation G00 G00 G00 G00 G00 G00 Fume cupboard G0 G0 Laminar flow booth G0 G0 Ventilated workbench G0 G0 Storage General storage G0 G0 G0 G0 G0 G0 Dust extraction Removing waste from dust extraction unit G0 G0 G0 Transfer Conveyor transfer G05 G05 Sack filling G06 G07 Sack emptying G08 Filling kegs G09 Charging reactors/mixers from a sack or keg G0 G0 IBC filling and emptying G Drum filling G Drum emptying (drum pump) G Weighing Weighing G0 G G0 Mixing Mixing G0 G5 G6 G0 G7 G7 Sieving Sieving (+ filtering) G8 G8 Screening Screening G9 Surface coating Spray painting G0 G Powder coating G G Lamination Batch lamination G G Continuous lamination G G Dipping Pickling bath G5 G6 Vapour degreasing bath G7 G7 Drying Tray drying oven G8 G8 Continuous drying labyrinth oven G9 G9 Pelletising Pelletising G0 G0 Tablet press G 9 of 5 pages

Control Approach Containment Unit Operation Sheet title Solids Liquids Small Medium Large Small Medium Large General tasks Containment G00 G00 G00 G00 G00 G00 Glove box G0 G0 Storage General storage G0 G0 G0 G0 G0 G0 Dust extraction Removing waste from dust extraction unit G0 G0 G0 Transfer Transferring solids G0 G0 Sack emptying G0 Drum filling G05 G05 Drum emptying G06 Infrequent charging reactors/mixers from a sack or keg G0 G0 IBC filling and emptying G07 G08 Tanker filling and emptying G09 G0 Filling kegs G G Transferring liquid by pump G G Packet filling G0 G G Bottle filling G0 G G Weighing Weighing G0 G5 G5 G0 G6 G6 Mixing Mixing G0 G7 G7 G0 G8 G8 Surface coating Robot spray booth G9 G9 Automated powder coating G0 G0 Dipping Vapour degreasing bath G G G Drying Spray drying G G G G Pelletising Tablet press G Control Approach Special Sheet No G00 G0 Title General principles Health surveillance for occupational asthma Control Approach S Chemicals causing harm by skin contact Sheet No S00 S0 Title Skin or eye contact Selecting personal protective equipment 0 of 5 pages

Appendix : HSG9 look-up table Look-up table to select Control Approach according to Hazard Group, amount, and dustiness or volatility (reproduced from HSG9) Amount used Low volatility or dustiness Medium volatility Medium dustiness High volatility or dustiness Hazard Group A substances Small Medium Large Hazard Group B substances Small Medium Large Hazard Group C substances Small Medium Large Hazard Group D substances Small Medium Large Hazard Group E substances All amounts Note: the values in the box give the Control Approach: Exposure Predictor Band The colour convention is carried through to COSHH essentials control guidance sheets, with the addition of: R where the control is principally RPE in addition to other measures. of 5 pages

Appendix : CHIP Risk (R) phrases and CLP-GHS Hazard (H) statements CHIP R-phrases R-no Phrase Group Note 0 Harmful by inhalation B Harmful in contact with skin B Harmful if swallowed B Toxic by inhalation C Toxic in contact with skin C 5 Toxic if swallowed C 6 Very toxic by inhalation D 7 Very toxic in contact with skin D 8 Very toxic if swallowed D Causes burns C 5 Causes severe burns C 6 Irritating to eyes A 7 Irritating to respiratory system C 8 Irritating to skin A 9 Danger of very serious irreversible effects - 0 Limited evidence of a carcinogenic effect D Risk of serious damage to the eyes C May cause sensitisation by inhalation E May cause sensitisation by skin contact C 5 May cause cancer E 6 May cause heritable genetic damage E 8 Danger of serious damage to health by prolonged exposure + 5 9 May cause cancer by inhalation E 60 May impair fertility D 6 May cause harm to the unborn child D 6 Risk of impaired fertility D 6 Possible risk of harm to the unborn child D 6 May cause harm to breastfed babies D 65 Harmful: may cause lung damage if swallowed A 66 Repeated exposure may cause skin dryness or cracking A 67 Vapours may cause drowsiness and dizziness A 68 Possible risk of irreversible effects E 6 Notes: All phrases now considered a risk on or via the skin. Based on evidence, experts can reduce Group from D to C or from C to B. Combination phrase. No impact of header number - use the Group for the other R-numbers. Old data sheets have R0 as a combination phrase. If so, treat as (). As (), but retain skin sensitisation in mixtures to a concentration of 0.%. 5 Combination phrase. Group for R-numbers in combination rises from B to C or from C to D. 6 If a combination phrase, as (); otherwise Group E. of 5 pages

CLP-GHS Hazard (H) statements H-stmt Phrase Group 00 Fatal if swallowed D 0 Toxic if swallowed C 0 Harmful if swallowed B 0 May be fatal if swallowed and enters airways A 0 Fatal in contact with skin D Toxic in contact with skin C Harmful in contact with skin B Causes severe burns and eye damage C 5 Causes skin irritation A 7 May cause an allergic skin reaction C 8 Causes serious eye damage C 9 Causes serious eye irritation A 0 Fatal if inhaled D Toxic if inhaled C Harmful if inhaled B May cause allergy or asthma symptoms or breathing difficulties if E inhaled 5 May cause respiratory irritation C 6 May cause dizziness or drowsiness A 0 May cause genetic defects (route if relevant) E Suspected of causing genetic defects (route if relevant) E 50 May cause cancer (route if relevant) E 5 Suspected of causing cancer (route if relevant) D 60 May damage fertility or the unborn child (effect if known, route if relevant) D 6 Suspected of damaging fertility or the unborn child (effect if known, route if relevant) D 6 May cause harm to breast-fed children D 70 Causes damage to organs (organ if known, route if relevant) C 7 May cause damage to organs (organ if known, route if relevant) B 7 Causes damage to organs through prolonged or repeated exposure (organ if known, route if relevant) D 7 May cause damage to organs through prolonged or repeated exposure (organ if known, route if relevant) C EU66 Repeated exposure may cause skin dryness or cracking A EU70 Toxic by eye contact E EU7 Corrosive to the respiratory tract C of 5 pages

References and further information COSHH essentials: easy steps to control chemicals (second edition) HSG9 HSE Books 00 ISBN 0 776 77 no longer available in hard copy, web-only version at www.coshh-essentials.org.uk Russell RM, Maidment SC, Brooke IM et al An introduction to a UK scheme to help small firms control health risks from chemicals Annals of Occupational Hygiene August 988 (6) 67-76 Brooke IM A UK scheme to help small firms control risks to health from exposure to chemicals: toxicological considerations Annals of Occupational Hygiene August 988 (6) 77-90 Maidment SC Occupational hygiene considerations in the development of a structured approach to select chemical control strategies Annals of Occupational Hygiene August 988 (6) 9-00 5 CHIP: Chemicals (Hazard Information and Packaging for Supply) Regulations 00 see HSE s CHIP web pages www.hse.gov.uk/chip/index.htm 6 CLP: Regulation (EC) No 7/008 on classification, labelling and packaging using GHS: United Nations Globally Harmonised System of Classification and Labelling of Chemicals see HSE s GHS web pages www.hse.gov.uk/ghs/index.htm 7 Control of Substances Hazardous to Health (COSHH) Regulations 00 (as amended) see HSE s COSHH web pages www.hse.gov.uk/coshh/index.htm 8 Control of substances hazardous to health (Fifth edition). The Control of Substances Hazardous to Health Regulations 00 (as amended). Approved Code of Practice and guidance L5 (Fifth edition) HSE Books 005 ISBN 978 0 776 98 7 9 Topping MD, Williams CR, Devine JM Industry s perception and use of occupational exposure limits Annals of Occupational Hygiene August 988 (6) 57-66 0 Tischer M, Bredendiek-Kamper S, Poppek U Evaluation of the HSE COSHH essentials exposure predictive model on the basis of BAuA field studies and existing substances exposure data Annals of Occupational Hygiene August 00 7(7) 557-569 REACH: Registration, Evaluation, Authorisation and Restriction of Chemicals. See HSE s REACH web pages www.hse.gov.uk/reach/index.htm Respiratory protective equipment at work: A practical guide HSG5 (Third edition) HSE Books 005 ISBN 978 0 776 90 6 Further information HSE priced and free publications can be viewed online or ordered from www.hse. gov.uk or contact HSE Books, PO Box 999, Sudbury, Suffolk CO0 WA Tel: 0787 8865 Fax: 0787 995. HSE priced publications are also available from bookshops. of 5 pages

For information about health and safety ring HSE s Infoline Tel: 085 5 0055 Fax: 085 08 9566 Textphone: 085 08 9577 e-mail: hse.infoline@natbrit.com or write to HSE Information Services, Caerphilly Business Park, Caerphilly CF8 GG. This document contains notes on good practice which are not compulsory but which you may find helpful in considering what you need to do. This document is available web-only at: www.coshh-essentials.org.uk/assets/live/ CETB.pdf Crown copyright This publication may be freely reproduced, except for advertising, endorsement or commercial purposes. First published 09/09. Please acknowledge the source as HSE. Published by the Health and Safety 09/09 5 of 5 pages