Noise Induced Hearing Loss and Hearing Conservation in 8 Primary Iron and Steel Companies in South Africa Presenters: Dr Odette Abrahams Gabriel Mizan
Background Noise: Sound that is undesirable, either because it annoys, distracts or interferes with those hearing it or because it has the potential to damage the hearing mechanism of those exposed to it SA Dept of Mineral and Energy (2000)
Noise Induced Hearing Loss (NIHL) Cumulative, permanent loss of hearing that develops gradually after months or years of exposure to high levels of noise Commonest compensable occupational disease globally One of the major avoidable causes of permanent hearing impairment worldwide WHO estimated that occupational NIHL costs approximately 0.2% to 2% of the GDP of developed nations
Factors Affecting Employees Susceptibility to NIHL Intensity of the noise (db) Temporal pattern of the noise (continuous, intermittent) Spectral pattern of the noise (frequency content) Duration of exposure Individual susceptibility to noise (age, ear infection, certain medication)
Statutory Requirements NIHL Regulations, promulgated under the OHSAct 85 of 1993 require the employer to implement HCP when workers are exposed to noise rating limit > 85 db (A) Compensation for Occupational Injuries and Diseases Act No 130 of 1993 compensable at or above PLH of 10 % as per Schedule 3 Circular Instruction 171 provides further guidance on compensation of employees
The Study NIOH was commissioned by the DoL to investigate noise exposure levels and NIHL in the primary Iron and Steel in South Africa Iron and Steel industry in one of the largest employers in SA with approximately 55 000 employees South Africa is the 21 st largest crude steel producing in the world (7.6 m tonnes /year) Iron and Steel manufacturing is one of the noisiest industries and NIHL is common
Study Objectives 1. To verify the current designation of noise zones as described in companies occupational hygiene reports 2. To verify workers noise exposure levels by taking spot area measurements and personal noise exposure (dosimetry) 3. To analyse and audit current hearing conservation practices 4. Based on company records, to determine the extent of NIHL diagnosed by the companies over the past decade
Study Objectives 5. To verify records of current hearing threshold levels of workers by independently conducting audiometric testing 6. To compile recommendations for improvement of existing hearing conservation practices that can be implemented in the South African iron and steel industry 7. Based on best practices and expert advice, to develop a standard inspector checklist for noise in the iron and steel industry
Methodology
Methodology Cross sectional survey in 8 major iron and steel companies across SA Company Type of industry No of permanent No of contract employees employees Company A Primary steel plant 7000 6808 Company B Primary steel plant 541 328 Company C Primary steel plant 650 753 Company D Secondary steel 246 6 plant Company E Primary steel plant 2700 2100 Company F Primary steel plant 2587 2354 Company G Primary steel plant 1696 450-500 Company H Primary steel plant 2711 310
Phase 1: Occupational Hygiene Study Walkthrough / task observations Interviews with H&S personnel, workers, clinic Area (spot) noise measurements Personal noise measurements (dosimetry) Review of previous noise survey reports and other relevant documentation
H&S Manager Questionnaire Covered various aspects of HCP including: Information and training Assessment of exposure Survey report and recommendations Medical surveillance Hearing protection equipment Policies and procedure
Worker s Interview Questions When were you last given training on noise? What are the main health risks of noise? Do you use hearing protection in your job? What type of hearing protectors do you use? Will you show me how do you put on hearing protectors correctly? When last did you have a hearing test? Do you experience any difficulties with your hearing? Do you have any concerns regarding noise in this workplace? Input / Observation
Phase 2: Occupational Medicine Hearing conservation Policy ý Interview check list used ý Copy of the company policy ý Interview was then compared to the written policy Medical Record Review Review of NIHL Audiometric verification
Response Rate Company Response rate in the chosen department Response rate in the NIHL employees Company A 100% 100% 56.7% Company B 100% 100% 66.7% Company C 100% a 89% Response rate for audiometric retesting Company D Not ascertained b Company E 63.4% 77.8% 77.4% Company F 42.6% 17.1% 56.8% Company G 38.7% 0% 83.3% Company H 66.7% 100% 50% a Employee records were available but not all were reviewed due to time constraints. b Employees consent for review of records was only concluded during the survey and hence a random sample could not be obtained.
Findings
Company Policy on Hearing Conservation Programme A B C D E F G H Exposure Assessment / Noise Risk Assessment + ---- + + + + ---- + Identification of employees at risk Noise Monitoring & Assessment + ---- + + + + ---- + + + + + + + ---- + Noise Control + ---- + + + + ---- + Employee Training & Education + + + + + + ---- + Baseline& Periodic Audiometric Testing + + + + + + ---- +
Assessment of Noise exposure Area measurements: 78% of measurements in the Iron & Steel Industry departments exceeded the 85 db (A) limit Personal noise dose measurements: 68% of exposures exceeded 85 db (A)
Factory Average Noise level db(a) per Department Steel Production & BOF Coke plant &cutting area Cold Mill Galvanizing & Temper Mill Sinter Plant A 84 86 92 94 98 Off line (Recycle) Melt Shop Mills B 94 94 102 Iron making, Corex&Midrex Hot Strip Mill Hot Strip Basmnt Steel Mill Melt Shop C 87 88 90 95 QC Small parts & Core Shop Sand Plant Fettling & VW Production Foundry & Prod D 81 94 94 102 102 Coke Plant & Steel Plant Unitrans Bar Mill Billet Bar Rod Mill Iron Blast Furnace E 88 90 94 97 Structures Work Shop Iron Plant Melt Shop Flat Products Steel Plant 1 & 2 & Mill Pulverized Fuel F 78 85 88 90 98 Hot & Cold Process Lines Final Lines Plate Process & cutting Steel Plant G 83 92 99 106 Area Noise Measurements Foundry Heavy & Ball Forge Foundry Medium Melt Shops Hille Mille, Morgan & DRI Pl. Wheel Pl & HCBP H 85 93 95 96 103
Noise Measurements Area The distribution of 406 area noise measurements in db(a): 10 20 60 145 <85 >85 & <90 >90 & <95 >95 & <100 75 >100 & <105 96 >105
MSOffice5 Noise Measurements Dosimetry The distribution of 127 personal noise dose measurements in db(a): 20 4 30 <85 >85 & <90 >90 & <95 29 44 >95 & <100 >100
Slide 21 MSOffice5 The cake slice for <85 is too large there should be less than half., 2012/10/18
Percentage area and personal noise measurements >85dB(A) at eight Iron and Steel factories 100 90 Percentage >85 db(a) 80 70 60 50 40 30 20 Area noise Personal noise dose 10 0 A B C D E F G H Factory
Noise Control Practices Reusable ear plugs, ear muffs and custom made HPDs were used Noise control engineering options were not used to their fullest advantage
Double glazed noise refuge control room
Information and Training All companies had an information and training programme conducted by health & safety officers or SAQA accredited trainers Training within the 1st year of employment and on moving to a noisy department with > 85dB(A) Training was initially done at induction and then annually in 6 of 8 companies
Information and Training 43 out of 111 (39%) workers interviewed could not remember when last trained on noise 96% of workers interviewed understood the health risk related to noise 39% of workers could not demonstrate how to fit their HPDs correctly 27% of the workers were concerned about noise in their work environment 11% reported problems with their hearing
Medical Surveillance All 8 companies conducted baseline, periodical and exit audiograms
Baseline Audiometric Testing Baseline done in accordance with Instructiion 171 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 98% 97% 98% 93% 93% 86% 68% 69% 32% 32% 14% 7% 7% 2% 3% 2% A B C D E F G H Yes No Companies
Periodic Audiometric Testing % Compliance with frequency of periodic audiometric testing 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 100% 100% 100% 100% 98% 89% 72% 28% 11% 2% 0% 0% 0% 0% 0% A B C D E F G H yes No Companies
Periodic Audiograms: Evidence of PLH shift Evidence of threshold shift from baseline on periodic audiogram 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 84% 48% 46% 36% 37% 32% 28% 17% 14% 10% 0% 0% A B C D E F G H Companies Yes No Unclear
Recorded Actions Following Evidence of Hearing Decline Evidence of threshold shift : no of employees Nothing recorded in the medical file Test was repeated after no exposure to noise Diagnostic audiogram was done More training was done The employee was relocated A 10 20% 40% 60% 10% 0 B 37 92% 8% 0 8% 0 C 11 73% 0 9% 23% 0 D a Unobtainable E 21 76% 15% 9% 0 0 F 10 50% 10% 0 50% 0 G 26 96% 4% 0 4% 0 H 6 17% 33% 67% 0 0
Noise Induced Hearing Loss 9 8 7 8.3 Estimated average annual incidence (per 1000/year) Incidence/1000/year 6 5 4 3 2 1 0 4.1 2.4 1.4 1.5 1.5 0.7 0.6 A B C D E F G Ha Companies Ha Calculated over from 2008 for Company
Recorded Actions Following NIHL Diagnosis Company No. of employees with NIHL Referred for compensation More training Relocation Dismissed Other than referral for compensation, no evidence of other actions A 37 100% 22% 11% 0 68% B 21 86% 0 0 0 100% C 9 100% No consent granted D 10 100% No consent granted E 7 100% 14% 29% 0 0 F 7 86% 43% 0 0 57% G No consented obtained H 6 83% 0 0 0 33%
Audiometric verification Aim: To compare a sample of audiograms done inhouse at each company with audiograms done by an external service provider on the same employees.
Audiometric verification A B C D E F G H Audiograms for comparison 16 20 20 19 24 21 20 12 Concordant 8 0 4 0 2 2 4 0 10 19 db difference 3 3 10 7 11 14 14 6 20 29 db difference 5 7 6 9 8 3 2 4 30 39 db difference 0 4 0 1 3 1 0 2 >40 db difference 0 6 0 2 0 1 0 0
Limitations Industrial action affected response rate adversely OH measurements could not be done of every activity Incomplete medical records Extent of NIHL company records of cases over the past 10 years were used (underestimation) Reliance on companies to provide cases of NIHL (validation) Only permanent employees
Limitations Audiometric verification Currently no reference body for audiometric testing in the workplace No gold standard testing facility Measured repeatability rather than of validity External provider chosen based on calibrated equipment and a national footprint Many factors affect repeatability however this indicates that a review of quality assurance and testing procedures by in house testers is required
Conclusion All companies included in this survey had areas of noise exposure above the legislated level of 85dB(A) which put a number of employees at risk of developing NIHL Difference between the companies lies in the effective implementation of the hearing conservation programme Highlights the need for proper implementation of hearing conservation practices known to be effective and establishment of effective monitoring and evaluation systems
Good Practices: Policy and procedures Written health and safety policies are available (7/8) Hearing conservation related matters Ø Ø reported discussed by employees during toolbox talks and in committee meetings (8/8) Proactive hearing conservation programmes demonstrated noticeable outcomes (2/8) Managers seen to be committed to the noise conservation programme (4/8)
Good Practices Assessment of Noise Exposure Assessments re done after major changes made in work systems and machinery (8/8) Records of these were made available to Safety Representatives and Safety Committee (8/8) Recommendations in reports were practical and actioned according to a plan in line with hierarchy of control (5/8)
Good Practices: AIA Survey reports and recommendations AIAs were used in the noise exposure assessments (8/8) Reports were available and repeated on the average every 24 months (6/8)
Good Practices: Noise Control Practices Good general maintenance of machinery, equipment and tools led to less noise (3/8) Custom made HPDs were provided to selected employees, notably those with early decline in hearing or based in areas with very high noise exposure (5/8) Signage and noise zoning is implemented (8/8) SOPs on noise control were available (4/8)
Good Practices: Information and Training Specialised noise training sessions Training content was in line with the appropriate medical surveillance programme Training records were kept (4/8) Refresher training was conducted annually (3/8) Information and training programmes delivered by competent persons (8/8) Strategies in place to increase uptake of training with objective means (tests) to evaluate effectiveness of training (4/8) Incentive schemesfor employees who (1/8): Ø completed training Ø show evidence of understanding information
Good Practices: Medical Surveillance Occupational Medicine & Occupational Hygiene services share information and updates on noise exposure levels (2/8) Baseline and periodical audiograms are done in accordance with SANS 10083 (5/8) Software is utilised to analysis aggregated audiometric results of audiometric testing in order to identify any trends suggesting review of workplace controls (2/8) Documentation of noise exposure & management s intention for each employee with results that need to be acted upon (3/8)
Good Practices: Medical Surveillance Individual employee audiogram analysed by OHP and OMP to identify permanent or temporary threshold shift (8/8) Early intervention by clinic staff on hearing loss before 10PLH is reached (some companies action is taken at 5PLH ) (4/8) OM staff give feedback to Occupational Hygiene and Safety services and employee representatives (2/8)
Good Practices: Noise Induced Hearing Loss Employees diagnosed with NIHL who showed a 10 PLH were appropriately referred for diagnostic audiograms and subsequently submitted for compensation (8/8) Health and Safety Representatives were involved in the assessment of the employee (5/8) Audiometric testing done on all employees exposed to noise exceeding 85 db(a) (8/8)
Recommendations: Policy and Procedures All companies should have a policy and an SOP on NIHL Policy should detail: Responsibilities of stakeholders : Health and Safety team, occupational hygienists or contracted AIA, occupational clinic staff, training department, supervisors and employees Noise Evaluation and Surveillance Procedures in noise areas, measure noise exposure Noise Control Practices Engineering and administrative controls, HPDs (types, selection, issuing, use & maintenance )
Recommendations: Policy and Procedures The policy should detail: Medical Surveillance Audiometric Testing and an action plan for remedial measures Training Program Record Keeping Program Evaluation Main company policy can be customized to meet local needs at of multiple sites HCP should be the same for both permanent and contracted employees
Recommendations: Noise Control Practices All workers must be involved in noise control Health and Safety Reps must be involved in the implementation of noise control Workers involved in the selection of hearing protectors to improve buy in Training and supervision of workers including contractors in the correct wearing of HPDs (e.g. earplugs) in noise zones
Recommendations: Information and Training Training should be regular, practical, evaluated and given by a competent person to both permanent and contracted employees
Recommendations: Medical Surveillance Good communication between the OH and the medical staff Action lines prior to the employee having compensable hearing loss Systems to ensure that regular audiograms as appropriate Well preserved medical files Aggregated audiogram should be communicated to multi disciplinary team
Recommendations: Audiometric verification Level of professional conduct should be maintained in terms of certification and calibration of quipment used and staff performing testing Quality assurance programmes for audiometry are imperative
Recommendations: Noise Induced Hearing Loss Workers with a PLH deterioration of more than 10% require a diagnostic audiogram and formal referral for compensation A specific formal written plan to be in place for employees who have compensable hearing loss to prevent further worsening of their condition.
Acknowledgements Department of Labour The staff in all facilities who supplied us with all the information that was needed, arranged for our visit and availed themselves to handle our queries and clarify other issues as we went through files in such a gracious and professional manner.
Thank You