CONCEPTUAL MODEL 417 Conceptual model A number of similar models are used in OH practice to summarize and guide the process of assessing and managing risks in the workplace and the environment. One examp le is given in Fig. 21.1. n o i t p e c r e p n o i t a c n u m m o c e c n a l l i k s i R h t l a e H k s i R i e v r u s t n e m e g a n a m k s i R : h t l a e H k s i R . g n h s i l l a n o i t a p u c c O i b u P t n e m e g a n a m d n a y c n e g r e m E n o i t n e v e r P s c m o n o c E l o r t n o c & g n n n a l p i l l i e w k c a l B , l a p m a R t n e m e g a n a M y t e f a S d n a h t l a e H f o n o i s s i w e v e R d n a . G K d n a t n e m i . n o i t a z i r e t c a r a h c t n e m m r e p e v i t a t i t n a u Q s s e s s a s s e s s a a r h d a S k s i R t i d u A y B k s i r . ) 9 9 9 1 ( k s i r . h t l a e h S . t n e m e g a n a m y t e f a s t h g i r y p o C t n e m l a n o i t a p u c c O t n e m g n e r u s o p x E e r u s o p x E s s e s s a i l l e d o m s s e s s a . t n e m e g a n a M d n a k s i R d n a l a c g o o m e d p E h t l a e H l a c g o o c x o T n o i t a c i f i t n e d t n e m t n e m i l a c n i d r a z a H l i l t n e m s s e s s a s s e s s a i i l c & 1 1 2 . i s s e s s a i i . g i F 21_Smedley_Chap21.indd 417 1/2/2013 12:33:17 PM CHAPTER 21 Risk assessment and risk management 418 General principles Risk assessment Assessing the risks and bene \201 ts from a possible co urse of action requires evaluation of relevant scienti \201 c evidence. There are four mai n elements to this. Typically, these elements are described in relation to potential advers e effects, but bene \201 cial effects can be considered analogously. \200 Hazard identi \201 cation: what are the potential adverse effects of the agent or circumstance? Hazard characterization: how does the probability of these hazards vary according to the nature and extent of exposure? Exposure assessment: what are the nature and extent of the exposures that will occur if the course of action is followed? Estimation of risk: what is the likely probability of each hazard if the course of action i s followed? For each risk estimate there should be an evaluation of the associated scienti \201 c uncertainty (might the true risk be much larger or smaller than the \201 gure est imated, and if so, how likely is this?). Risk management Risk management entails the application of value judgements to decide betwe en possible courses of action, given the estimated risks and bene \201 ts associated with each option. Value judgements should re \202 ect the inter- ests of all people who could b e materially affected by the decision, with greatest weight being given to the interests of those who will be most affected. Who makes the decision will depend on the number of people affected. If the important risks and bene \201 ts involve only one person, then ideally that individual should decide whic h option to follow. If more than one person will be affected and their interests con \202 ict, then the decision may require societal input (e.g. through an elected government or th e judiciary). For example, governments set exposure limits on hazardous substances in the w orkplace, taking into account the interests of both workers and employers. Frameworks for the assessment and management of risks Where complex, but similar risk manag ement decisions must be made on a regular basis (e.g. in the regulation of toxic chemicals in the workplace), a generic framework may be established within which risks are assessed a nd managed. This has the advantage of transparency (it is easier for affected parties to un derstand the basis on which decisions are made) and pro- motes internal consistency of deci sions. For example, the framework for regulation of pesticides in the EU speci \201 es sta ndard requirements for sci- enti \201 c data and the approaches that should be used to det ermine whether potential risks will be acceptable. 21_Smedley_Chap21.indd 418 1/2/2013 12:33:17 PM GENERAL PRINCIPLES 419 The precautionary principle As de \201 ned in 1992, the precautionary principle stated tha t \200\230where there are threats of serious or irreversible damage, lack of full scienti \201 c cer- tainty shall not be used as a reason for postponing cost-effective meas- ures to prevent environmental degradation \200\231. It has since been extended to encompass haza rds to health as well as to the environment. Essentially, it is an af \201 rmation that de cisions in risk management should take appropri- ate account of scienti \201 c uncertainty . 21_Smedley_Chap21.indd 419 1/2/2013 12:33:17 PM CHAPTER 21 Risk assessment and risk management 420 Sources of scienti \201 c evidence and uncertainty Sources of scienti \201 c evidence on hazard and risk Information about hazard and risk may come from various sources: \200 Ext rapolation from accepted scienti \201 c theory: for example, in assessing the health risks from static magnetic \201 elds, account is taken of the relevant principles of biophysic s Experiments in vitro : e.g. tests for mutagenicity in bacteria \200 Toxicological experim ents in live animals: these can be more informative, but are relatively expensive and must be justi \201 able in relation to the impact on animal welfare Studies investigating risk in humans: these may be experimental (e.g. randomized controlled trials (RCTs)) or observational (e.g. cohort and case-control studies). They have the adva ntage of avoiding the uncertainties of extrapolation between species, but are limited by th e practical and ethical constraints on research in humans. Moreover, they can only be condu cted after human exposure to a potentially hazardous agent has occurred Studies to assess patterns of exposure that may result from a risk management decision: depending on the nature of the exposure, these may use methods of occu pational hygiene, ergonomics, microbiology, psychology, or other scienti \201 c discipline s. Reasons for scienti \201 c uncertainty Scienti \201 c uncertainty in the assessment of ri sks may occur for various reasons. \200 Doubts about the validity of accepted scienti \201 c theory and of its extrapolation to the exposure of interest Possible differences in susceptibility to a hazard between humans and the animal species in which toxicology has been investigated, sometimes taken into account by application of an \200\230assessment factor \200\231 ( \200\230safety factor \200\231) Possible differences between individuals in susceptibility to a hazard (e.g. because of differences in genetic constitution, sex, age, coincident disease, and med ication, or aspects of lifestyle and environment). Again, an assessment factor may be used to allow for this De \201 ciencies in the design or execution of studies \200 Statistical uncertainties wh en results are based on \201 nite samples of observations that may be unrepresentative by chance. Con \201 dence intervals can be used to help gauge the potential for error of thi s type. 21_Smedley_Chap21.indd 420 1/2/2013 12:33:17 PM RISK COMMUNICATION AND PERCEPTION 421 Risk communication and perception Risk communication Good communication of risk is importan t for two main reasons: \200 People who take decisions in risk management ( \200\230risk managers \200\231) need to understand the likely risks and bene \201 ts of each possible c ourse of action. This information must be conveyed to them by the scientists who have asses sed the risks and bene \201 ts Where decisions in risk management are made at a societal level, the people affected need t o understand the basis on which decisions are made, and to have an opportunity for informed contribution to the decision-making (e.g. through consultation processes or lobbying of po liticians). 2 Conveying a clear assessment of risk is not easy, especially when the target audience is not scienti \201 cally trained. Language should be tailored to the audience, and it may he lp to draw analogies with other risks that are more familiar (e.g. how risk compares with t hat of a road traf \201 c accident or from living with a smoker). (cid:2) It is best to av oid referring to a situation as \200\230safe \200\231, since nothing in life can ever be g uaranteed as totally free of risk. The term \200\230at risk \200\231 is also unhelpful wit hout some indication of the level of risk implied. Perceptions of risk The value judgements that are applied in risk management will depend on people \200\231s perceptions of hazards, risks, and uncertainties. A number of factors in \202 uence perceptions. \200 The nature of the hazard: this encompasses not only the gra vity of the hazard (e.g. is it life-threatening?), but also its nature (e.g. cancer may gen erate more fear than heart disease even though the risk of fatality is similar). The risk of the hazard being realized. \200 The timeframe within which the risk will appl y: is it transient (e.g. the risk of acute injury from undertaking a dangerous activity), p rolonged (e.g. the risk of cancer from ionizing radiation), or delayed (e.g. the risk of ca ncer from taking up smoking)? Whether the risk is offset by an obvious personal bene \201 t: e.g. there is more public concern about risks from mobile phone masts than from mobile phones themselves, although the latter give higher exposures to radiofrequency radiation. Whether the risk is voluntary or imposed. \200 The familiarity of the risk: risks that ar e well understood (e.g. of road traf \201 c accidents) are less threatening. Risk experience: e.g. someone who has lost a relative to cancer is likely to be more worrie d about contracting the disease themselves than someone who has had no personal experience of it. 21_Smedley_Chap21.indd 421 1/2/2013 12:33:17 PM This page intentionally left blank 423 Chapter 22 Health surveillance Health surveillance: general principles 424 Skin surveillance 426 Respiratory health survei llance 428 Classi \201 cation of hearing loss 430 Patterns of hearing loss 432 Inorganic l ead 434 Organic lead 436 Surveillance for hand \200\223arm vibration syndrome 438 22_Smedley_Chap22.indd 423 1/2/2013 12:34:37 PM CHAPTER 22 Health surveillance 424 Health surveillance: general principles General principles \200 Health surveillance shoul d only be introduced where the risk assessment indicates that it is required (Regulation 6, Management of Health and Safety at Work Regulations 1999) or it meets the criteria listed in the associated Approved Code of P ractice: \200 an identi \201 able disease or adverse effect is associated with the work activity appropriate methods are available to identify such ill effects \200 it is reasonably like ly that the adverse effect will occur given the prevailing work conditions health surveillance will offer additional protection to the workforce \200\231s health Health surveillance should be supported by a health surveillance policy agreed between mana gement and the employees or their representatives The health surveillance policy should document the roles and responsibilities of the line manager, employee, OH service, and HR department The health surveillance policy should clearly state how results are to be handled and records stored Where an employee \200\231s continued \201 tness for work may be affected by the outcome of health surveillance, an agreed policy on redeployment should be in place Informed consent to participate in the health surveillance program should be sought from each employee at the outset The consequences of refusal to participate in health surveillance where this is legally req uired for work with an agent/process should be made explicit. Frequency of health surveillance \200 An initial assessment of \201 tness is required p rior to exposure commencing. This provides a baseline against which subsequent changes can be compared. In a ddition, it identi \201 es those workers with pre-existing de \201 cits not attributable to that employment Thereafter, the risk assessment dictates the frequency of workers \200\231 health surveilla nce unless published guidance stipulates a greater frequency of checks. Quality assurance \200 All staff involved in health surveillance should be appropriately trained and understand the purpose of the surveillance program Equipment used for health surveillance should be well maintained, regularly calibrated, and \201 t for purpose Any samples taken for health surveillance, e.g. biological monitoring should be analyzed in a laboratory that participates in a recognized quality assurance program Any abnormal results should be checked and repeated before further action is taken. 22_Smedley_Chap22.indd 424 1/2/2013 12:34:37 PM HEALTH SURVEILLANCE: GENERAL PRINCIPLES 425 Results The results of health surveillance should be fed back to the worker and a decision made on his/her continuing \201 tness for work. If a predetermined action level is exceed ed, the employer should investigate the reasons for this and review the ef \201 cacy of co ntrol measures. Grouped, anonymized, results of health surveillance should be fed back to staff and the hea lth and safety committee. No personally identi \201 able data should be disclosed except t o the individual employee unless consent has been given for such release. The health surveillance program should be regularly audited and any adverse trends investigated and acted on. Health records \200 An entry documenting the individual \200\231s \201 tness status ( \201 t/ \201 t with restrictions/un \201 t) for work with the relevant agent should be made in the worker \200 \231s health record and be sent to their employer The medical surveillance records should be retained by the OH health service for 40yrs. Relevant legislation HSE (2000). Management of Health and Safety at Work Regulations 1999 , Approved Code of Practice and Guidance, 2nd edn, L21. HSE Books, Sudbury. HSE (2005). The Control of Substances Hazardous to Health Regulations 2002 (as amended), Approved Code of Practice and Guidance, L5. HSE Books, Sudbury. Faculty of Occupational Medicine (2006). Guidance on Ethics for Occupational Physicians , 6 th edn. FOM, London. 22_Smedley_Chap22.indd 425 1/2/2013 12:34:37 PM CHAPTER 22 Health surveillance 426 Skin surveillance Skin surveillance is appropriate where there is a recognized risk of occu pa- tional skin disease as de \201 ned in COSHH 2002, Regulation 11. This decision may be based on previous experience, Manufacturer \200\231s Safety Data Sheets (MSDS), or industry advice. Following the introduction of new agents sus- pected of causing skin problems, ski n surveillance may be instituted. (cid:2) Value of skin surveillance is contested by some o ccupational physicians. A recent NHS Plus systematic review failed to \201 nd any publish ed evidence regarding skin surveillance for occupational hand dermatitis. Frequency Frequency of skin inspection depends on the agents in use. Monthly skin inspectio n is usual. Methods \200 Annual hand dermatitis screening questionnaire to identify those workers who need to be seen by an OH professional for assessment. (cid:2) Such questionnair es should be validated against direct skin inspection in that workforce: some questionnaire validation studies have shown disap- pointing agreement levels with direct skin inspection . \200 Regular skin inspection of \200\230at-risk \200\231 staff by an OH nurse or a res ponsible person. Those deemed \200\230at-risk \200\231 may be based on: \200 occupationa l exposure, e.g. hairdressers \200 occupational exposure and a history of hand dermatitis Vinyl chloride workers must be subject to skin surveillance under the supervision of an HSE appointed doctor or employment medical adviser (EMA) Patent fuel manufacture from pitch: workers are subject to skin surveillance under the supervision of an HSE appointed doctor or EMA. Results \200 Individuals with skin problems should be referred to a medical practitioner for further assessment A health record should be kept as required by COSHH \200 Further tests may include: patch testing \200 skin-prick testing for urticaria \200 blood tests for IgE and RAST \200 skin biopsy (skin cancer). Relevant legislation and guidance HSE (1998). Medical Aspects of Occupational Skin Disease , guidance note MS24, 2nd edn. HSE Books, Sudbury. Available at: M http://www.hse.gov.uk/pubns/ms24.pdf 22_Smedley_Chap22.indd 426 1/2/2013 12:34:37 PM This page intentionally left blank CHAPTER 22 Health surveillance 428 Respiratory health surveillance Respiratory health surveillance is required under COSHH, Re gulation 11, for employees who are exposed to known respiratory sensitizers (asth- magens). The purpose is to identify cases of occupational asthma (OA) as early as possible. A list of asthmagens for which surveillance is likely to be required is given in b p. 198, Occupat ional asthma and rhinitis. Methods Screening methods \200 Questionnaire (baseline and follow-up) based on a symptoms checklist. Enquiry covers exposure in the proposed job, previous history of exposure to asthmagens, as thma, or work-related respiratory symptoms, and any changes to exposure or symptoms, during follow-up (see Box 22.1) Spirometry: forced expiratory volume in 1s (FEV 1 ) and FVC \200 Education: an important part of screening is to inform employees about the nature and level of the risk to their he alth, and to counsel them about early reporting of symptoms. Explanation should be given ab out the possibility of late symptoms. Format and frequency This depends on the level, duration, and frequency of exposure (and th erefore the risk of sensitization). Two levels of health surveillance are de \201 ned in H SE guidance (MS25, see b p. 429, Further information and guidance). \200 Low level: where there is only suggestive evidence of a hazard, or a low likelihood of exposure: \200 baseline questionnaire and spirometry \200 annual follow-u p questionnaire High level: where there is strong evidence of a hazard and it is not possible to exclude a risk of sensitization: \200 baseline questionnaire and spirometry \200 follow-up of newly exposed employees is by questionnaire (+ spirometry if the risk of sensitization is signi \201 cant) after 6wks and 12wks, respecti vely; the interval can fall to annually thereafter in the absence of positive \201 ndings . Responsible person Questionnaires may be administered by a responsible person (usually a li ne manager) who has been trained appropriately by an OH doctor or nurse. Positive questionn aire responses must be referred to a competent OH professional for further investigation. Investigation and management of potential cases This is usually carried out by an occupatio nal physician. \200 Investigation aims to distinguish the following: work-related from non-work-related disease \200\224usually possible from a detailed history and lung function, but may need further investigation by serial PEFR testing (see b p. 762 , Serial peak \202 ow testing) 22_Smedley_Chap22.indd 428 1/2/2013 12:34:37 PM RESPIRATORY HEALTH SURVEILLANCE 429 Box 22.1 Example questions for baseline questionnaire* 1. Do you believe that your chest ha s suffered as a result of previous employment? 2. Have you ever left a job because of your chest? 3. Do you have or have you ever had (do not include isolated colds, sore throats, or \202 u): a) Recurring soreness or watering of your eyes? b) Recurring bl ocked or running nose? c) Bouts of coughing? d) Chest tightness? e) Wheezing? f) Breathless ness? g) Any persistent of history of chest problems? Example questions for follow-up questionnaire* Since you last answered our questionnaire 1. Has your job changed? 2. Have you had any of the following symptoms? (list 3, a to g) * Ad apted from HSE sample questionnaire (see web reference in Further information and guidance) . true immunological sensitization (OA) from non-speci \201 c irritation of pre-existing rev ersible airways disease \200\224it is often impossible to distinguish these on history or P EFR testing alone. Exposure to a known sensitizing agent might give rise to a presumptive d iagnosis of OA. However, the gold standard investigation is speci \201 c broncho-provocati on challenge testing (see b p. 198, Occupational asthma and rhinitis) Management of OA: con \201 rmed cases should be restricted from exposure, or exposure controlled to the level where symptoms are not detectable. Frequent f ollow-up should occur if exposure continues. Other surveillance \200 Employers should monitor trends in sickness absence to detect any excess absence that might be due to allergic respiratory disease Useful information can be gained from exit interviews: employees with OA and rhinitis often select themselves out of work with the allergen. Further information and guidance HSE (1998). Health surveillance for occupational asthma. I n: Medical Aspects of Occupational Asthma , MS25. HSE Books, Sudbury. Available at: M http: //www.hse.gov.uk/asthma/employers. htm#health Sample baseline and follow-up questionnaires. Available at: M http://www.hse.gov.uk/asthma/ sam- plequest2.pdf; also available at: M http://www.hse.gov.uk/asthma/samplequest3.pdf BOHRF asthma review. Available at: M http://www.bohrf.org.uk/downloads/OA_Guide-1.pdf 22_Smedley_Chap22.indd 429 1/2/2013 12:34:37 PM CHAPTER 22 Health surveillance 430 Classi \201 cation of hearing loss Screening for hearing loss is required under the Contro l of Noise at Work Regulations 2005 ( b p. 548, Control of Noise at Work Regulations 2005). The method of screening is by audiometry ( b p. 764, Screening audiometry). Purpose of hearing loss classi \201 cation There are a number of hearing loss classi \201 cation systems developed for the purposes of: \200 Determining compensation in civil lit igation \200 Determining disability bene \201 ts \200 Monitoring hearing in audiometri c surveillance programs. One method of classifying occupational hearing loss which is emplo yed in the UK is that published in Appendix 5 of the HSE publication Controlling Noise at W ork 2005 . 2 Whether or not such a classi \201 cation scheme is employed all audiograms sh ould be reviewed by a competent health professional. Method of classi \201 cation using revised HSE scheme \200 The results of audiometry are summed across 1, 2, 3, 4, and 6kHz frequencies in each ear separately Audiograms are classi \201 ed using the information in Table 22.1 \200 Table 22.2 is use d to determine whether the hearing loss exceeds the warning or referral levels for that age band Where the sum for either ear is greater than or equal to the warning level for the worker \200\231s age and gender, he/she is graded category 2 (mild hearing impairment) Where the sum for either ear is greater than or equal to the referral level for the worker \200\231s age and gender, he/she is graded category 3 (poor hearing). Such individuals shou ld be referred to a doctor \200 Where the previous test took place within 3yrs and i in h earing threshold of 30dB or greater is found (as the sum of 3, 4, and 6kHz), the worker is graded category 4 (rapid hearing loss) and should be referred to an occupational physician or GP To assess unilateral hearing loss, take the sum of the hearing level at 1, 2, 3, and 4kHz f or both ears. If the difference between the ears is >40dB, notify the worker and refer for medical advice Where referral is indicated, an occupational physician should review the worker and conside r the need for further assessment by an ear, nose, and throat (ENT) surgeon. Actions following audiometry \200 Offer all workers advice on the use of hearing protecti on and the health effects of noise Workers in category 2 should be noti \201 ed of the presence, and implications of any hearing loss and the advice recorded in the OH notes Give workers a copy of their audiogram \200 Workers in category 4 may need audiometry mor e frequently. 22_Smedley_Chap22.indd 430 1/2/2013 12:34:37 PM CLASSIFICATION OF HEARING LOSS 431 Table 22.1 The HSE categorization scheme Category Calculation Action 1 Acceptable hearing ability Hearing within normal limits Sum of hearing levels at 1, 2, 3, 4, and 6kHz None 2 Mild hearing impairment Hearing within 20th percentile, i.e. hearing level normally exper ienced by 1 person in 5. May indicate developing NIHL Sum of hearing levels at 1, 2, 3, 4, and 6kHz. Compare value with \201 gure given for app ropriate age band and gender in Table 22.2 Warning 3 Poor hearing Hearing within 5th percentile, i.e. hearing level normally experienced by 1 person in 20. Suggests signi \201 cant NIHL Sum of hearing levels at 1, 2, 3, 4, and 6kHz. Compare value with \201 gure given for app ropriate age band and gender in Table 22.2 Referral 4 Rapid hearing loss Reduction in hearing loss of 30dB or more within 3yrs or less. Such a change could be caused by noise exposure or disease Sum of hearing levels at 3, 4, and 6kHz Referral Crown copyright, material is reproduced with the permission of the controller of HMSO an d Queen \200\231s Printer for Scotland. Table 22.2 Classi \201 cation of audiograms into warning and referral levels Age Sum of hearing levels 1, 2, 3, 4, and 6kHz Males Females Warning level Referral level Warning level Referral level 18 \200\22324 51 95 46 78 25 \200\22329 67 113 55 91 30 \200\22334 82 132 63 105 35 \200\22339 100 154 71 119 40 \200\22344 121 183 80 134 45 \200\22349 142 211 93 153 50 \200\22354 165 240 111 176 55 \200\22359 190 269 131 204 60 \200\22364 217 296 157 235 65 235 311 175 255 Crown copyright, material is reproduced with the permission of the controller of HMSO an d Queen \200\231s Printer for Scotland. Relevant guidance/legislation HSE (2005). Controlling noise at work , Guidance on the Contr ol of Noise at Work Regulations 2005, L108. HSE Books, Sudbury. Available at: M http:// www .hse.gov.uk/pubns/indg362.pdf 22_Smedley_Chap22.indd 431 1/2/2013 12:34:37 PM CHAPTER 22 Health surveillance 432 Patterns of hearing loss The audiogram varies with the age of the individual, the degree of noise exposure, and any co-existing auditory conditions. Normal audiogram Fig. 22.1 shows a normal audiogram of a young person with a hearing thresh old of approximately 0dBHL. In older workers the hearing thresh- old will be lower than thi s, although in most normal individuals it will remain above 20dBHL. Noise-induced hearing loss \200 Typically, noise-induced hearing loss will produce a notc h lying between 3 and 6KHz with recovery (see Fig. 22.2). This dip is usually most prominent at 4KH z In older workers with co-existing presbyacusis (age-related hearing loss) the audiogram may not show recovery at higher frequencies Firearms use can lead to hearing loss. Initially this loss may be unilateral, but with continued exposure the hearing loss will affect both ears although asy mmetry may be evident. Otosclerosis \200 This conductive hearing loss (Fig. 22.3) is due to an autosomal dominant disorder that causes progressive conductive deafness due to a localized disorder o f bone metabolism Family history may be positive \200 In women this disease may \201 rst present during o r following pregnancy \200 Typically, the audiogram shows hearing loss more marked at low frequencies than at high frequencies Carhart \200\231s notch may be observed with a dip at 2kHz. Frequency (KHz) Frequency (KHz) 4 1 2 3 4 6 8 0.5 1 2 3 6 8 0.5 0 0 Left Left 10 10 Right Right 20 20 30 30 ) L H B d ( ) L H B d ( 40 40 50 50 y t i s n e t n y t i s n e t n 60 60 I I 70 70 80 80 90 90 100 100 Fig. 22.2 Noise-induced hearing loss: X left; O right. Fig. 22.1 Normal audiogram: X left; O right. 22_Smedley_Chap22.indd 432 1/2/2013 12:34:38 PM PATTERNS OF HEARING LOSS 433 Frequency (KHz) Frequency (KHz) 1 2 3 4 6 8 0.5 1 2 3 4 6 8 0.5 0 0 Left Left 10 10 Right Right 20 20 30 30 ) L H B d ( 40 ) L H B d ( 40 50 50 y t i s n e t n y t i s n e t n 60 60 I 70 I 70 80 80 90 90 100 100 Fig. 22.3 Otosclerosis: X left; O right. Fig. 22.4 M ni re \200\231s disease: X left; O right. Frequency (KHz) 1 2 3 4 6 8 0.5 0 Left 10 Right 20 30 ) L H B d ( 40 50 y t i s n e t n 60 I 70 80 90 100 Fig. 22.5 Acoustic neuroma: X left; O right. M ni re \200\231s disease This condition (Fig. 22.4) produces a low-tone hearing loss often accom- panied by tinnitus. Acoustic neuroma \200 A schwannoma of the vestibulocochlear nerve. It presents with unila teral hearing loss (Fig. 22.5), tinnitus, and sometimes vertigo Workers with unilateral hearing loss and associated tinnitus should be referred for ENT inv estigations to exclude an acoustic neuroma: the diagnostic yield of such investigations is, however, low. 22_Smedley_Chap22.indd 433 1/2/2013 12:34:38 PM CHAPTER 22 Health surveillance 434 Inorganic lead Workers exposed to inorganic lead should be subject to health surveil- lance where breathing zone sampling indicates that the 8h TWA is greater than half the lead in a ir standard of 0.15mg/m 3 . 2 Only HSE EMAs/HSE appointed doctors should carry out such hea lth surveillance. Frequency of health surveillance An initial medical assessment of \201 tness for lead wor k is required together with a baseline blood lead and hemoglobin prior to commencement of w ork with lead. Consideration should be given to factors that may increase lead absorption: \200 Nail biting \200 Smoking \200 Poor personal hygiene. Thereafter, the work activi ty and/or blood lead level dictates the frequency of workers \200\231 health surveillance. As a minimum this means an annual clinical review, including: \200 Physical examination \200 Review of medical records \200 Review of blood lead levels \200 Other relevant te sts \200 hemoglobin \200 zinc protoporphyrin (levels in unexposed workers are usually <2 g/g hemoglobin). However, for women of reproductive capacity or young people health surveillance should take place at 3-monthly intervals. Maximum intervals for blood lead monitoring by blood lead levels Blood lead Maximum interval for surveillance <30 g/dL 12mths (cid:2) 30 \200\223<40 g/dL 6mths (cid:2) 40 \200\223<60 g/dL 3mths (cid:2) 60 g/dL At doctor \200\231s discretion, but not >3mths Samples A 5-mL blood sample should be collected in an EDTA tube. The timing of sampling is not critical. A laboratory participating in the joint HSE/UK NEQAS program should carry out atomic absorption spectroscopy to determine blood lead levels. 22_Smedley_Chap22.indd 434 1/2/2013 12:34:39 PM INORGANIC LEAD 435 Results \200 Results of blood lead monitoring should be fed back to worker and a decision made on their continuing \201 tness for work with inorganic lead If an action level is exceeded the employer should investigate the reasons for this and review the ef \201 cacy of control measures. Aim is to prevent the wo rker \200\231s blood lead level reaching the suspension level \200 Where the relevant sus pension level is reached, the appointed doctor must decide whether to certify that the empl oyee is no longer \201 t to work with lead. The Control of Lead at Work Regulations 2002 indicates the following action and suspension levels (Box 22.2). Box 22.2 Actions required for given blood lead level Action level Suspension level Adult (not of reproductive capacity) 50 g/dL 60 g/dL Young person 40 g/dL 50 g/dL Woman of reproductive capacity* 25 g/dL 30 g/dL A woman of reproductive capacity is a woman medically and physically capable of conceiving. This includes any woman on hormonal contraceptives. Background blood lead levels in the general population are usually <10 g/dL 2 Pregnant workers should be suspended from work involving signi \201 cant exposure to lead 3 Where a worker \200\231s blood lead level reaches the suspension level, the blood lead should be re-checked as a matter of urgency. Health records An entry documenting the individual \200\231s \201 tness for work with ino rganic lead should be made in his/her health record and be sent to his/her employer. The me dical surveillance records should be retained for 40yrs. Relevant legislation \200 HSE (2002). Control of Lead at Work Regulations 2002 , Approved Code of Practice and Guidance, L132. HSE Books, Sudbury. M http://www. hse.gov.uk/pubns/pr iced/l132.pdf HSE (2000). Management of Health and Safety at Work Regulations 1999 , Approved Code of Pra ctice and Guidance, 2nd edn, L21. HSE Books, Sudbury. 22_Smedley_Chap22.indd 435 1/2/2013 12:34:39 PM CHAPTER 22 Health surveillance 436 Organic lead Workers exposed to lead alkyls (e.g. tetraethyl lead, tetramethyl lead) should be subject to health surveillance where breathing zone sampling indicates that the 8h TWA is greater than half the lead in air standard of 0.10mg/m 3 or there is a risk of dermal ab sorption of lead alkyls. Most exposure to organolead occurs in the manufacture or use of le ad alkyls employed as anti-knock agents in leaded gasoline. 2 Only HSE EMAs/HSE appointed d octors should carry out such health surveillance. Frequency of health surveillance An initial medical assessment of \201 tness for lead wor k is required together with baseline urinary lead prior to work with lead commencing. Those with a recent history of psychiatric illness should not work with organic leads to avoid c onfusion between organic lead poisoning and a relapse of pre-existing mental illness. Consi deration should be given to factors that may increase lead absorption: \200 Nail biting \200 Smoking \200 Poor personal hygiene. Thereafter, the work activity and/or urine lead level dictates the frequency of workers \200\231 health surveillance. As a minimum this me ans an annual clinical review, including: \200 Physical examination \200 Review of medi cal records \200 Review of urinary lead \200 Annual blood lead. Samples A 25-mL urine sample should be collected at the end of the shift at the end of the working week. Analysis is by atomic absorption spectrophotometry to determine urinary lead levels. Results The results of lead monitoring should be fed back to the worker and a decision made on his/her continuing \201 tness for work with organic lead. Where the relevant suspensi on level is reached and is con \201 rmed by repeat testing, the appointed doctor will cert ify that the employee is no longer \201 t to work with organic lead. The Lead at Work Reg ulations 2002 indicate the following suspension levels (Box 22.3). \200 2 Pregnant worker s should be suspended from work involving signi \201 cant exposure to lead 3 Where a worker \200\231s urinary lead level reaches the suspension level, the urinary lead should be re-checked as a matter of urgency. Health records An entry documenting the individual \200\231s \201 tness for work with org anic lead should be made in his/her health record and be sent to his/her employer. The medi cal surveillance records should be retained for 40yrs. 22_Smedley_Chap22.indd 436 1/2/2013 12:34:39 PM ORGANIC LEAD 437 Box 22.3 Suspension levels for urinary lead Suspension level Adult (not of reproductive capacity) 110 g Pb/g creatinine Young person (aged 16 or 17) 110 g Pb/g creatinine Woman of reproductive capacity * 25 g Pb/g creatinine A woman of reproductive capacity is a woman medically and physically capable of conceiving. This includes any woman taking hormonal contraceptives. Relevant legislation \200 HSE (2002). Control of Lead at Work Regulations 2002 , Approved Code of Practice and Guidance, L132. HSE Books, Sudbury. available at: M http://www.hse.go v.uk/pubns/priced/l132.pdf HSE (2000). Management of Health and Safety at Work Regulations 1999 , Approved Code of Pra ctice and Guidance, 2nd edn, L21. HSE Books, Sudbury. 22_Smedley_Chap22.indd 437 1/2/2013 12:34:39 PM CHAPTER 22 Health surveillance 438 Surveillance for hand \200\223arm vibration syndrome The health surveillance requirements f or HAVS are described in the Control of Vibration at Work Regulations 2005. Main requirements Health surveillance should be provided for vibration-exposed employees wh o: \200 Are likely to be regularly exposed above the exposure action value of 2.5m/s 2 A(8) Are likely to be exposed occasionally above the exposure action value and where the risk assessment identi \201 es that the frequency and severity of expo sure may pose a risk to health Have a diagnosis of HAVS (even when exposed below the exposure action value). Process and methods The HSE recommends a tiered approach to health surveillance for HAVS. F urther information and example questionnaires are available through the HSE website (M http ://www.hse.gov.uk/vibration/hav). \200 Tier 1 \200\224initial baseline assessment: a shor t questionnaire to be used for people moving into a job involving exposure to vibration. Questionnaire responses determine whether the individual is referred for health assessment (tier 3) Tier 2 \200\224annual (screening) questionnaire: a short questionnaire to be used annually for individuals exposed to vibration, to determine whether they need to be referred to tier 3 Tier 3 \200\224assessment by quali \201 ed person: this involves a HAVS health assessment by a quali \201 ed person, e.g. an OH nurse. A clinical questionnaire asks about relevant symptoms, and limited clinical examination is recommended. If the assessment shows that the individual has HAVS, he/she should be referred to tier 4 Tier 4 \200\224formal diagnosis: at this stage a formal diagnosis is made by a doctor quali \201 ed in OH. The reported history of symptoms is considered to be the most useful diagnostic information. Information from tiers 1 \200\2234 is also used to make decisions on \201 tness for work \200 Tier 5 \200\224standardized tests (optional): th is stage is optional and involves referral for certain specialized tests for individuals wh o have signs and symptoms of HAVS. Tests include: \200 Vascular tests: \201 nger rewarming after cold provocation (CPT) \200 \201 nger systolic blood pressu re test (FSBP) Senosorineural: vibrotactile perception threshold (VPT) \200 thermal (temperature) perception threshold ( TPT). 22_Smedley_Chap22.indd 438 1/2/2013 12:34:39 PM SURVEILLANCE FOR HAND \200\223ARM VIBRATION SYNDROME 439 Symptoms related to carpal tunnel syndrome may need to be investigated by nerve conduction tests (see b p. 294, Compression neuropathies). \200 Specialist training is required to c arry out clinical assessments for HAVS. The Faculty of Occupational Medicine (UK) has developed a syllabus for approved train ing in health surveillance for HAVS \200 As part of the health surveillance program a rec ord-keeping system is needed for results of reports of symptoms and medical examinations. Related legislation Occupational cases of HAVS and carpal tunnel syndrome are reportable to HSE by the employer under RIDDOR 1995. Further information HSE (2005). Hand arm vibration: the Control of Vibration at Work Regula tions 2005 . HSE Books, Sudbury. HSE. Health Surveillance \200\224guidance for occupational health professionals. Available at: M http://www. hse.gov.uk/vibration/hav 22_Smedley_Chap22.indd 439