Nebosh_Dip_Assignment_B

1.0 INTRODUCTION The factory employs 75 process workers in an open plan environment. The production area uses mainly computer numerically controlled (CNC) machines that perform a variety of cutting and machining tasks on medium density fibre board (MDF) panels of varying thicknesses. These have edging glued on and manually assembled onto metal frames to produce a range of office furniture. The cutting, drilling and routering processes of the MDF create hazardous dust. Machine operatives work close to the source of dust for the duration of their 8-hour shift. MDF is a type of man-made hardboard produced from wood fibres glued under heat and pressure. Urea Formaldehyde is commonly used as the gluing agent and presents health hazards in addition to normal wood dust. The elimination or control of risks from MDF dust is required by the Health and Safety at Work Act (HASWA)1, the Control of Substances Hazardous to Health (COSHH)2 Regulations, the Management Regulations3, and the Dangerous Substances and Explosive Atmospheres Regulations (DSEAR)4 . References to source documents made throughout this paper use the Vancouver system and are listed in the bibliography . 1. AIMS To investigate the implications to employees’ health from the dust generated during the processing of MDF panels. What procedures should be followed to identify and assess the hazards in compliance with current legislation and guidelines and to establish if the risks of exposure can be eliminated or controlled to an acceptable level. To review the effectiveness of existing control measures and investigate the cost effectiveness of implementing additional ones. 2. OBJECTIVES • Detail the properties of MDF and identify the health hazards created by cutting, drilling and routering. Identify and explain possible routes of entry and their effects on target organs. • Formulate a risk assessment that fully addresses all aspects of the MDF dust producing work activities and meets the requirements of current legislation and associated guidance. • Describe means by which employee exposure to the identified hazards can be prevented, where reasonably practicable, or is adequately controlled in accordance with the duties imposed by the COSHH Regulations2. • Assess the effectiveness of existing control measures and identify any additional cost effective ones. 2.0 MAIN BODY 2.1 MDF Characteristics and health hazards The type of wood used in the composition of MDF cannot always be specifically identified but that manufactured in the UK typically contains 85% softwood and 15% hardwood. MDF originating from countries where hardwoods are more available will contain a higher proportion of hardwood. It is manufactured to European Standards5 by a dry process which employs a bonding agent of synthetic resin commonly urea-formaldehyde based. This substance presents additional potential health hazards which must be considered in conjunction with the effects of both soft and hardwood dusts. Because of the hazardous properties of urea-formaldehyde, MDF is now available bonded with formaldehyde-free synthetic resins. A study has been carried out6 to identify the amount, particle size and the physical makeup of dust created during the machining of different types of MDF compared with machining pure wood. It establishes that the coarsest dust is produced during sawing operations and the finest during sanding. In addition to the hard and softwood components of MDF the respective binding agent has the potential to be absorbed into the dust particles giving rise to the possible release of free formaldehyde. 2.1.1 Hardwood Dusts Although the proportion of hardwood in the composition of MDF is significantly less than softwood the respirable fraction of airborne dusts generated in machining operations is twice as great. The main health hazard from exposure to hardwood dust is sino-nasal cancer. Mucostasis, which reduces the rate at which dust is cleared from the nasal passages, is caused by the inhalation of hardwood dusts and has occurred in workers exposed to average dust levels higher than 2mg/m-3. Exposure to hardwood dusts have been clearly linked with adencarcinoma of the nasal cavity. 2. Softwood Dusts Particle sizes from the softwood component of MDF are larger and in consequence the respirable portion is about half that for hard woods. The prime effect of concern for exposure to softwood dusts is occupational asthma7. This may be classified as Allergic which is a reaction to a substance by the immune system or Irritant which is a reaction to a substance not involving the immune system causing a dysfunction to the airways. Symptoms may include: • Attacks of wheezing, coughing, chest tightness or shortness of breath • Rhinitis (sneezing, runny nose) and/or • Conjunctivitis (itchy and inflamed eyes) There is some evidence to suggest that a different historical type of sino-nasal cancer to that caused by hardwood dusts may be attributable to softwood dusts. Where workers have been exposed to total dust concentrations of 2mg/m-3 symptoms of respiratory irritation have occurred. 3. Formaldehyde The main health concern about exposure to formaldehyde is local irritation to the eyes nose and throat. Evidence suggests that though this irritation can bring on the symptoms of asthma in susceptible individuals it does not induce asthma. Formaldehyde is chemically reactive and highly soluble in water therefore any inhaled is retained in the upper respiratory tract preventing little if any reaching the lungs. Studies have failed to establish a link between formaldehyde and cancer of the lung, nasal passages or nasopharynx. Following some concern that formaldehyde absorbed into MDF dust could result in respirable particles penetrating into the lower respiratory tract, studies have provided no clear evidence of any difference in the toxicological response to formaldehyde in either the upper respiratory tract or lungs. 2.1.4 Workplace Exposure Limits (WELs)8 have been assigned for Hard and Softwood dusts and for formaldehyde. Hard and softwood dusts each have an 8-hour Time Weighted Average (TWA) of 5mg/m-3 (total inhalable dust) both with a Sen notation signifying they are capable of causing occupational asthma, and formaldehyde 2ppm as both an 8-hour TWA and a 15-minute Short Term Exposure Limit (STEL). Hardwood dust is also listed in Schedule 1 of the COSHH Regulations2 as a carcinogenic substance. 1. Hazards to Health Health hazards from dust created during the machining of MDF panels fall into the following categories: • Respiratory system (inhalation) • Skin (absorption) • Physical (Fire/explosion) 1. Respiratory System The most significant route of entry for MDF dusts is by inhalation. Dust concentration in air is measured by weight in a given volume (mg/m-3) and particle size measured in microns (µm). The particle size determines its ability to penetrate the body’s natural defence mechanisms as either Inhalable or Respirable dust. The respiratory system consists of a trachea (windpipe) which branches into bronchi feeding into the right and left lungs. These divide further into the alveoli to perform the lung’s main function of gas exchange. Inhalable dust consists of larger particles of dust, those over 10 microns can be trapped by nasal hair. Smaller particles of between 5 and 10 microns are prevented from penetrating into the alveoli by the muco-cillary escalator in the bronchi and bronchioles. Respirable dust consists of particles smaller than 5 microns that can penetrate into the alveoli and pose the greatest hazard to health. 2. Absorption The main effect is skin irritation. Areas affected are likely to be the backs of the hands, forearm, the face, neck scalp and genitals. The symptoms remain only for as long as contact with the dust is present. More difficult to eradicate is sensitisation or allergic dermatitis, whose symptoms are similar to skin irritants. Once sensitised the body sets up an allergic reaction which can subsequently be triggered by exposure to very small amounts of MDF dust. 2.2.3 Fire and Explosion Given the right concentration of dust/air mixture a significant risk of explosion is created. The accumulation of wood dust on work surfaces, floor and building structure can increase the overall fire risk of the workplace. 3.0 Assessment of Risk Section 2 of HASWA1 places duties on employers to protect the health safety and welfare of their employees. The requirement to assess and control risks created by work activities is further detailed by regulation 3 of the Management Regulations 3 , and where hazardous substances are involved regulation 6 of the COSHH Regulations2 applies. As the machining processes of MDF create airborne dust the requirements of regulation 5 of DSEAR4 must be addressed. Guidelines on the sampling and analysis of respirable and inhalable dusts are contained in MDHS 14/39 . In order that effective control measures are formulated the distinction between hazard and risk must be clearly understood: Hazard The innate ability for a substance or work activity to cause harm. Risk The likelihood that the identified hazard will cause harm in the circumstances of use. Methodology [pic][pic] 3.1 Step 1: Gathering Information An assessment of the health risks posed by the machining processes of MDF requires the identification of the machines/work activities that are dust producing. Use of a dust lamp as detailed in the HSE information leaflet10 has established that the prime sources are: |ID |LOCATION |PROCESS |SUBSTANCES | |T5 |Machining Area |Homag Small Saw |Hard/Softwood Dusts | | | |(S/N MC 0054051) |+ formaldehyde | |T2 |Machining Area |Homag Large Saw |Hard/Softwood Dusts | | | |(S/N 341-07-5811) |+ formaldehyde | |S3-S5 |Machining Area |IDM Edge Bander |Hard/Softwood Dusts | | | |(S/N 305-99-0538 |+ formaldehyde | |PT1- |Machining Area |Wood Machining Machine |Hard/Softwood Dusts | |PT3 | |(S/N 5664-2) |+ formaldehyde | |TI&P2 |Machining Area |New Homag |Hard/Softwood Dusts | | | |(S/N 20-15-2536) |+ formaldehyde | |T3 |Machining Area |Bench Router |Hard/Softwood Dusts | | | |(S/N 260-06-0488) |+ formaldehyde | In order to establish the nature and extent of the hazards it is necessary to identify the concentration of airborne dusts in the workplace in general and in particular the operator area. A basic air sampling configuration is shown below. 3.1.1 Active Personal Samplers These consist of a belt mounted battery powered air pump connected by flexible hose to a collector mounted close to the respiratory zone. A suitable filter element collects dust particles from the air drawn through it over a pre-determined period (usually 8 hours). This filter can subsequently be analysed and the concentration of dust determined as a ratio of mg/m-3. The presence and concentration of formaldehyde is determined using a similar method but a stain tube is fitted that will react to the target substance. Actual exposure, measured in parts per million (ppm). Results are compared with WELs8 and the relevant Material Safety Data Sheet (MSDS). 2. Other factors To enable the Risk Assessment to be effective further data is collected including: • The routes of exposure (inhalation, skin contact/absorption, ingestion) • The exposure frequency • Duration of exposure • Existing control measures. 1. Step 2: Risk Assessment Regulation 6 of COSHH2 requires that the Risk Assessment should consider the hazards to health of all the tasks involved in the work process and all those that may be affected by them. Its purpose is to identify measures to prevent or adequately control employees’ exposure to hazardous substances at work. This process should involve observation and interviewing the process workers in conjunction with the results of workplace monitoring. The process must be carried out by a competent person as defined by paras 255-259 of the ACoP11. A standard proforma is used to ensure a logical and consistent approach to the assessment. A sample proforma is at Appendix A. 3.3 Step 3: Additional Measures May identify further control measures to prevent or reduce exposure potential. Regulatory requirements may require: • Maintenance of controls such as the periodic inspection of LEV equipment at intervals not exceeding 14 months. • Ongoing monitoring of exposure to confirm the effectiveness of control measures. • Health surveillance at suitable intervals to confirm the effectiveness of control measures and monitor any pre-existing medical conditions. • To provide suitable information of the health hazards and provide appropriate training. 4. Step 4: Record Keeping Each Risk Assessment is given a unique serial number, signed and dated by the assessor. A register of all assessments is kept. All those who may be affected by the work process must read the assessments and a register of their receipt, understanding and compliance kept. 3.5 Step 5: Review Risk Assessments have a maximum review date identified at the time of issue. This date may be influenced by the assessor’s confidence in his initial findings. A review is always carried out when an existing assessment’s validity is in doubt due to: • A legislation change. • Introduction of new equipment/different materials/work practices. • Following and accident or incident. • A complaint from an operative. 4. Compliance with the COSHH 2 Regulations Regulation 6 of the COSHH regulations require control measures to be implemented to eliminate the source of hazard where reasonably practicable or to introduce control measures to reduce the level of exposure to within defined levels. To eliminate the hazards completely would necessitate the ceasing of all machining operations of MDF panels and contracting those work processes out. Some reduction in hazards would be achieved by the use of formaldehyde free MDF panels. However, these present the lowest risk due to the levels recorded. An effective dust extraction and collection system is required to reduce dust levels as low as reasonably practicable which also address the requirements of DSEAR4 in reducing the risk of explosion or fire due to the ignition of airborne particles. Pre-employment medical screening of employees to include lung function tests and subsequent regular health monitoring is required. In addition, the issue of suitable respiratory protection equipment (RPE), overalls and barrier cream is necessary. Suitable information on the hazards posed by MDF dust should be provided in conjunction with training in the application of effective control measures. When used in conjunction with bi-annual air sampling to confirm the effectiveness of these control measures the duties imposed by the regulations have been met. 1. Comparison of existing and proposed control measures The Homag T2 Large Saw produces the largest volume of dust of all the company’s machines. Existing control measures consist of Local Exhaust Ventilation located adjacent to the cutting blade and dust masks that are available to the operator but the wearing of them is not enforced. The Risk Assessment below identifies the Risk Rating without control measures, the reduction achieved by existing measures and the further reduction achievable with further control measures. The implementation of these would then create full legislative compliance. Risk Assessment |Serial No: BOF/012 |Activity/Equipment: MDF Panel cutting /Homag T2 Large Saw – S/N 341-07-5811 | |Date of assessment: 28 Apr 06 |Date for review: Apr 07 | |Description of hazards | |Airborne MDF dust with urea-formaldehyde content: Inhalation causing respiratory irritation, occupational asthma, nasal | |cancer. Skin contact causing irritation and sensitisation dermatitis. Ingestion causing gastric irritation | |Identified Substances |WEL | |Controlled | | |(8hrs TWA) TWATWA) |Uncontrolled | | | | | | | |MDF Dust |5mg/m-3 |9.2mg/m-3 |4.1mg/m-3 | |Formaldehyde |2ppm – |1.5ppm |1ppm | | |2.5mg/m-3 | | | | |(HSC to review limit| | | | |values) | | | | | | | | |Persons Affected | |Saw operator | |Existing Control Measures | |1. Local exhaust Ventilation adjacent to cutting bed. | |2. No eating, drinking or smoking in the workplace. | |3. Face masks available but wearing not enforced | |Risk rating with existing control measures (1 Low – 5 High) | |a) Likelihood: 3 b) Severity: 4 c) (a x b) Risk: 12 | |Risk rating without control measures (1 Low - 5 High) | |a) Likelihood: 4 b) Severity: 5 c) (a x b) Risk: 20 | |Recommended Additional Control Measures | |1. Fully integrated dust extraction and collection system – projected reduction in controlled levels of hazardous dust of | |50%. | |2. Pre-employment medical screening including lung function tests | |3. Annual health surveillance | |4. Air sampling – bi-annually | |5. Suitable Respiratory Protection Equipment provided and its wearing enforced | |6. Overalls & barrier cream provided | |Risk rating with additional control measures | |a) Likelihood: 1 b) Severity: 2 c) (a x b) Risk: 3 | | | | | |Assessor |Name: |Signature: | It can be seen that existing control measures contain levels of dust within the WELs8 by a narrow margin with only minimal control measures in place and do not address containment and disposal of extracted dust. No pre-employment medical screening takes place or subsequent health surveillance. Air sampling is not done regularly and consequently there is little to ensure that hazardous dust levels are contained within prescribed limits. Implementation of the recommended additional control measures achieves an immediate significant reduction in dust levels with the corresponding reduction in health hazards, fire and explosion risks. 5.0 Conclusions 1. MDF Properties and Health Hazards MDF is composed of hard and softwood fibres bonded together with a urea-formaldehyde resin. When machined dust is emitted presenting significant hazards to health. The main route of entry is via the respiratory system through either inhalable or respirable dust. Inhalable dust consists of the larger particles most of which are trapped in the upper respiratory tract whereas the finer particles, termed respirable, are able to penetrate into the gas exchange regions of the lungs with potentially more damaging effects. The hardwood respirable dust element can be the cause of sino-nasal cancer through mucotastasis. Softwood element is the primary cause of occupational asthma. The bonding agent used is urea-formaldehyde which can produce irritation to the eyes, nose and throat and can bring on the symptoms of asthma in susceptible individuals but does not induce asthma. Formaldehyde is readily soluble in water and chemically reactive therefore any that is inhaled is retained in the upper respiratory tract. There is no clear evidence of causation of cancer. WELs8 have been assigned to hard and softwood dusts. Hardwood dust is listed as a substance to which the definition carcinogenic applies. 2. Assessment of Risk Regulation 6 of the COSHH2 regulations require a suitable and sufficient Risk Assessment to be carried out by a competent person. As there is an additional hazard of fire and explosion, not covered by COSHH, the requirements of regulation 5 of DSEAR4 must be met. Additional guidance is provided by MDHS 14/39. The Risk Assessment identifies the hazards produced by the work activity and formulates reasonably practicable control measures to restrict exposure to acceptable levels. In order that the assessment is suitable and sufficient the assessor must be competent as defined in 255-259 of the ACoP11. Risk Assessments should be produced in a simple format that is easy to understand and have an appropriate review date nominated. Earlier review may be required should there be a change in legislation, new equipment or work practices, after an accident or incident or following a complaint from an employee. 3. Compliance with the COSHH Regulations2 Regulation 6 requires exposure to hazardous substances to be avoided, were reasonably practicable, or adequately controlled. Contracting-out all dust producing machining processes would achieve the former. If this is not possible reasonably practical control measures must be implemented. These should include an effective extraction and collection system, pre-employment medical screening of employees followed by regular health surveillance. Regular air sampling will ensure control measures remain effective. The issue of suitable Personal Protective Equipment (PPE) as identified by Risk Assessment will ensure that the duties required by the regulations are met. 5.4 Comparison of existing and proposed control measures The control measures in place on the Homag T2 Large Saw consist of LEV located adjacent to the cutting blade and the issue of face masks to the operator. Current levels of hazardous airborne dust are marginally within the WELs8. No pre-employment medical screening is carried out or subsequent health monitoring and the issue of PPE is minimal. Additional control measures introduce a fully integrated dust extraction and collection system projected to reduce current dust levels by 50% which effectively reduces the Risk Rating by 75%. The additional recommended measures are required to fully satisfy the duties placed by the COSHH2 regulations and include procedures to establish employees’ medical condition prior to employment and to subsequently monitor it to ensure any pre-existing conditions do not worsen or new ones appear. 6.0 Recommendations 6.1 Cost Benefit Analysis The recommended additional control measures must be “reasonably practicable”. This means their costs are not grossly disproportionate to the benefits. A disproportion factor (DF) is calculated as a ratio of costs against benefits. A Cost Benefit Analysis alone does not constitute an ALARP case or argue against statutory compliance. Ill health values used from HSE source11 Permanently incapacitating illness - £193,100 Other cases of ill health - £ 2,300 + £180 per day of absence Minor - £ 530 Based on company records, annual ill health costs have been factored to 1 x 25% in each category. | | | | | | |Serial |Item |Cost |Benefit |Saving | | | |(£) | |(£) | |1 |Installation of full integrated dust |40000 |Reduction in airborne dust levels of 50% |N/A | | |extraction/collection system | | | | |2 |Pre-employment medical screening |3750 |Establish medical condition prior to |N/A | | | | |employment | | |3 |Bi-annual air sampling 2 @ £3000 |6000 |Monitor effectiveness of control measures|N/A | |4 |Provide suitable RPE and enforce wearing in areas |1500 |Legislative compliance |N/A | | |indicated by Risk Assessment | | | | |5 |Provide overalls and barrier cream |500 |Skin protection |N/A | |6 |Employers Liability Insurance | |10% reduction for lower claims |600 | |7 |Ill health costs | |Improved control measures reduce costs by|36736 | | | | |75% | | |8 |HSE prosecution for non-compliance | |Full compliance avoids £20k fine |20000 | | |Total Costs |51250 |Total Benefits |57336 | Costs > 1 X DF Therefore 51250 = 0.89 - Additional measures are Benefits 57336 reasonably practicable 6.2 Action Plan for Implementation of Recommendations | | | | | | |Serial |Action |Cost |By Whom |Timescale | | | |(£) | | | | |Install fully integrated dust extraction/collection system to| | | | |1 |MDF dust producing machines |40000 |External |3 months | | | | |Contractor | | | |Initiate pre-employment medical screening to include lung | | | | |2 |function tests |3750 |HR Manager |1 month | | |Arrange bi-annual air sampling | | | | |3 | |6000 |Production Manager|Commence in 1 month | | |Purchase suitable RPE to meet identified requirements in | | | | |4 |Risk Assessments. |1500 |Production Manager|1 month | | |Brief Supervisors to enforce wearing where required | | | | | |Purchase suitable protective overalls and install barrier | | | | |5 |cream dispensers in wash rooms |500 |Stores Manager |1 month | | |Review progress of all actions | | | | |6 | |N/A |All Managers |Monthly | Detail Serial 1 The installation of an integrated extraction system removes the need for individual LEV equipment at each machine. It facilitates a more effective control measure as it controls airborne dust both at the work station and provides a sealed collection point ready for disposal. Serial 2 The initiation of pre-employment screening, provides a cost effective data start point for on-going medical monitoring and as evidence in any future employee claims. Serial 3 Current irregular air sampling does not provide sufficient information to adequately monitor the effectiveness of control measures. A bi-annual schedule will achieve this. Serial 4 Existing face masks are of questionable effectiveness in protection from inhalable dusts. Wearing is currently optional. RPE specific to the hazard is required and it wearing enforced by Supervisors where Risk Assessment requires it. Serial 5 Protective clothing and barrier cream will reduce dust contact on exposed parts of the body. Serial 6 A review of progress should be included as an agenda item at monthly management meetings to ensure that progress is made as planned. Bibliography 1. The Health and Safety at Work etc Act 1974. 2. The Control of Substances Hazardous to Health 2002 (as amended). 3. The Management of Health and Safety at Work Regulations 1999. 4. The Dangerous Substances and Explosive Atmospheres Regulations 2002. 5. BSI, 1997a,b; TRADA, 1995c. 6. Chung KYK, RJ Cuthbert, GS Revell, SG Wassell and N Summers (1999). 7. HSE – Occupational Asthma: A Guide for Employers, Workers and their representatives. 8. HSE – EH40/2005 Workplace Exposure Limits. 9. MDHS 14/3: General methods for sampling and gravimetric analysis of respirable and inhalable dust. 10. HSE – Woodworking Leaflet No12: Assessment and Control of wood dust – Use of a dust lamp. 11. Control of Substances Hazardous to Health Regulations 2002 (as amended) Approved Code of Practice and Guidance (Fifth Edition). Appendix A: Risk Assessment |Serial No: |Activity/Equipment: | |Date of assessment: |Date for review: | |Description of hazards | | | |Identified Substances |WEL | | | | |(8hrs TWA) |Uncontrolled |Controlled | | | | | | | | | | | |Persons Affected | | | |Existing Control Measures | | | |Risk rating with existing control measures (1 Low – 5 High) | | | |a) Likelihood: b) Severity: c) (a x b) Risk: | |Risk rating without control measures (1 Low - 5 High) | | | |a) Likelihood: b) Severity: c) (a x b) Risk: | |Recommended Additional Control Measures | | | |Risk rating with additional control measures | | | |a) Likelihood: b) Severity: c) (a x b) Risk: | | | | | |Assessor |Name: |Signature: | Appendix B: Proposed Integrated Dust Extraction and Collection System ----------------------- Step 1 Hazard & Task Identification Gather information on the: • Individual tasks • Who may be affected • Hazardous substances present • Hazardous effects (Safety Data Sheets) • Workplace/personal monitoring • Existing controls Step 2 Risk Assessment Make a balanced & informed judgement on the: • Risks to health for each task • Adequacy of existing controls Use: • Observation • Inquiry • Monitoring results • Step 3 Additional Measures Specify any additional measures to: • Prevent or adequately control exposure potential. • Meet any additional regulatory requirements such as: ➢ Maintenance of controls ➢ Exposure monitoring ➢ Health surveillance ➢ Instruction & training Record Keeping Step 5 Review Risk Assessments must be reviewed periodically when their validity nay no longer be valid due to: • Change of legislation • New work practices/materials • New equipment • Accident or incident • Complaint Step 4 Record Keeping Record the Risk Assessment and its recommended control measures in a suitable format for ease of interpretation, and long term archiving