The Control of Major Accident Hazards (COMAH) regulations 1999 are implemented by a Competent Authority (CA) comprising of the Health & Safety Executive (HSE) working jointly with the Environment Agency (EA) & the Scottish Environment Protection Agency (SEPA).
This report covers the period April 2001 to March 2002 and provides details of 4 COMAH major accidents in England, Wales & Scotland notified to the European Commission (EC). The report describes the causes of the accidents, their consequences and the enforcement action taken by the CA. In publishing it, the CA is aiming to show how the COMAH regime is working in an open and transparent way. The report will also enable lessons to be learned so that accidents can be prevented in the future.
The COMAH regulations 1999 apply to approximately 1100 establishments that have the potential to cause major accidents because they use, or store, significant quantities of dangerous substances, such as oil products, natural gas, chemicals and explosives. The general duty of the regulations is that ‘Every operator shall take all measures necessary to prevent major accidents and limit their consequences to persons and the environment’. The regulations are unusual in that they are implemented by a Competent Authority (CA) comprising of the Health & Safety Executive (HSE) working jointly with the Environment Agency (EA) and the Scottish Environment Protection Agency (SEPA). This arrangement reflects the requirements to ensure the protection of both persons and the environment.
The CA is required to notify certain major accidents to the EC. The criteria include; the release of a specified quantity of a dangerous substance, specified harm to persons (e.g. 1 death), specified harm to the environment (e.g. significant damage to more than 10km of river) or in some circumstances a ‘near miss’ of particular technical interest. This report describes the 4 EC Reportable Accidents (ECRAs) that occurred during the period 2001/02, their consequences and enforcement action taken by the CA. A summary is provided in tabular form at Appendix A.
The key points to note are that of the 4 accidents:
The principal conclusions are:
In April 1999 the Control of Major Accident Hazards (COMAH) Regulations came into force in England, Wales and Scotland, replacing the Control of Industrial Major Accident Hazards (CIMAH) Regulations that had been in place since 1984.
The COMAH regulations require the CA to notify the EC of certain major accidents. This is a continuation of the CIMAH requirements and there have typically been an average of 4 such accidents in the UK each year. The EC uses the data to inform its decisions on future changes to legislation regarding major accident hazards. The data is also made publicly available, including on the Internet, so that it can be used to learn lessons from the past and help to prevent accidents in the future.
This report provides details of the 4 COMAH major accidents notified to the EC between April 2001 and March 2002. It is the third report to be published in the series following the reports covering 1999/00 and 2000/01. The CA intends to publish the report for the period 2002/2003 in 2004.
The first European Council directive concerned with controlling major accident hazards involving dangerous substances was adopted in 1982. Known as the 'Seveso' directive, (82/501/EEC), it was incorporated into UK law by means of the Control of Industrial Major Accident Hazards Regulations 1984 (CIMAH). In 1996, the 'Seveso II' directive (96/82/EC) superseded the earlier Directive. The principal changes were a broadening of scope to include a wider range of dangerous substances and enhanced requirements to protect the environment. Most of the requirements of 'Seveso II' have been implemented by the COMAH Regulations 1999.
The general duty of the COMAH regulations is that 'Every operator shall take all measures necessary to prevent major accidents and limit their consequences to persons and the environment'. The regulations apply to over 1100 establishments in England, Wales and Scotland. Approximately 730 are ‘lower tier’ sites, where operators must prepare a Major Accident Prevention Policy. The remaining 370 sites with larger inventories of dangerous substances are classified as ‘top tier’ and are subject to additional requirements. These include submitting a safety report to the CA to demonstrate how they are preventing or limiting the consequences of a major accident and providing information to local authorities to enable off-site emergency plans to be developed.
COMAH Regulation 21 requires the CA to notify the EC of any major accident meeting certain criteria. The criteria and the information to be provided are given in Schedule 7 of the regulations. Part 1 is reproduced as Appendix B of this report.
The notifications are sent to the Major Accident Hazards Bureau of the European Commission Joint Research Centre (JRC), based at Ispra in Italy. The Bureau gives support to Environment Directorate General (DG ENV) of the European Commission. There are 2 forms provided for the purpose; the short form is for immediate notification of an accident and provides basic information, the long form is to be sent later when the investigations have been completed and the causes of the accident have been established.
The data is entered onto the Major Accident Reporting System (MARS). The names and addresses of the operators are removed before the data is made available to the public on the JRC website. Data searches and analyses can also be carried out on-line. For further information contact Michalis Christou, European Commission, Joint Research Centre, TP 670, I-21020 Ispra (Va), Italy. Email: email@example.com or by fax: +39 0332 78 9007.
4 major accidents were reported to the EC because they satisfy one of the criteria given in paragraph 1 of Schedule 7 of the COMAH Regulations.
The 4 accidents are listed below in chronological order. Details are provided against each accident on the causes, consequences, the emergency response and the action taken by the CA.
This COMAH top tier site is an oil refinery. On 16 April 2001, following the release of approximately 179 tonnes of extremely flammable hydrocarbon gases (a mixture of ethane, propane and butane), a fire broke out in the Saturate Gas Plant.
The incident occurred when the de-ethaniser column overhead pipework failed, resulting in the escape of the hydrocarbons. The escaping gas formed a vapour cloud and exploded. The ignition source for the cloud was a nearby coking plant direct-fired heater. Once ignited, the fire led to two further line ruptures and subsequent fireballs.
Both on-site and off-site Fire Services attended the scene and the police set up roadblocks in the surrounding area. There were three minor injuries reported: one on-site and two off-site. All on-site personnel were evacuated from the immediate vicinity. There was extensive damage off-site to local homes and businesses, including shattered windows and damage to roller shutter doors and lightweight panels in the adjacent industrial units. There was no damage to the environment.
This was an ECRA as it resulted in a fire and the loss of more than 5% of the qualifying quantity of dangerous substances as laid out in Part 1 of schedule 7 of the COMAH regulations.
Subsequent to the incident, the CA issued an alert advising refinery operators to ensure that pressure pipework was properly inspected and maintained, particularly where it was vulnerable to internal corrosion/erosion.
The incident is still under investigation by the CA.
At the time of the incident, this treatment plant for processing chemical waste was a COMAH lower tier site. On 16 July 2001 there was a release of an estimated 186m3 of hydrogen sulphide gas from a 500m3 treatment tank.
A road tanker load of waste alkali solution (approximately 20 tonnes) had been transferred to a treatment tank. As part of the chemical waste treatment process, mixed waste acids were added to the tank with a view to controlling the pH level (the measure for determining the strength or weakness of acids/alkalis). During the processing, the acid reacted with the polysulphide contaminants in the waste alkali solution, producing hydrogen sulphide gas. The tank had no lid and this resulted in the escape of the toxic gas from the tank. The gas then settled at ground level.
Fire, Police and Ambulance Services all attended the scene and remained for approximately 8 hours, until it was certain the site had been made safe from the threat of further releases. The local area surrounding the site was cordoned off by Police and public traffic excluded. There was 1 fatality from asphyxiation and 3 other injuries to employees who were all taken to hospital suffering from the effects of exposure to hydrogen sulphide gas. The gas left the site and its pungent smell was detected in the vicinity. There was no evacuation and no damage to the environment.
This was an ECRA as laid out in Part 1 of schedule 7 of the COMAH regulations, as it resulted in serious danger to human health and involved the release of one or more dangerous substances. Note: although neither of the waste products involved in the incident were in themselves the subject of COMAH Regulations notification, mixing them caused the formation of a dangerous substance.
An investigation by the CA revealed that there had been insufficient analysis of the waste chemicals (prior to treatment in the tank) to determine the nature and volume of toxic gas that would be generated during processing. There was evidence of inadequate maintenance, as the lid of the tank had severely corroded, to the extent it had collapsed into the tank. The extraction system was neither designed for, nor adequate for use with an open vessel and could not prevent the loss of containment of the toxic gas formed.
HSE brought 3 charges under the Health and Safety at Work etc Act 1974 Section 2, reflecting the most serious failings, i.e. the failure of the tank lid; an ineffective extraction system; the failure to provide suitable and sufficient safe systems of work for the treatment of waste streams likely to evolve toxic gases, including hydrogen sulphide.
The company pleaded guilty at Magistrates Court in September 2002 to the first two charges and was committed to Crown Court for sentencing. The company pleaded guilty to the 3rd charge on indictment to Crown Court on 20 January 2003 and a total fine of £250,000 was imposed.
As a result of several incidents in the chemical waste industry, an enforcement initiative has been carried out nationwide to look more closely at the industry and its safety/environmental standards.
Other emerging issues/factors relevant to the incident:
Mixing of incompatible chemical substances and wastes
Procedures for receipt and classification of waste materials
Maintenance strategy for structural integrity of storage tanks and associated ventilation systems
This COMAH top tier site refines oil and markets refinery products. Late on 27 September 2001 there was a release of 16.10 tonnes of liquid propane from the emergency drain valve of a fully laden road tanker. The tanker was in the parking area at the Immingham Pipeline Centre loading terminal, adjacent to other vehicles and positioned approximately above the drain interceptors. The release lasted for a period of 2 hours 10 minutes.
The release occurred when a vehicle fitter was attempting to drain off liquid propane for sampling into a metal bucket. He went underneath the rear of the tanker on a crawler board and removed the weather cap from the emergency drain line. He then fitted an in-house designed and constructed adaptor and hose/valve assembly onto the emergency drain valve outlet of the tanker. Once fitted, he attempted to use the assembly but nothing came out. In order to investigate the problem, the fitter closed the tanker globe valve to enable him to remove the bespoke assembly unit. However, the tanker globe valve remained partially open, resulting in the spillage of almost a full tank of liquid propane. There is an excess flow valve fitted upstream on the globe valve, but this did not operate because it is designed as an emergency measure only and responds to full-bore flow, rather than low-flow leaks.
Both the Emergency Response Team from the nearby refinery and the local Fire Service attended the scene. The emergency lasted for approximately 6 hours. The Port Authority and neighbouring establishments were also alerted. The off-site emergency plan was not implemented. The fitter suffered minor frost burns to his cheek and arm. A substantial quantity of liquid propane entered the surface water drains and reached the oil/water interceptors. The liquid propane flashed off there but did not ignite. The pressure lifted the interceptor covers, resulting in damage to the underside of the adjacent vehicles estimated at £5000. A structural inspection of the interceptors using closed circuit television was estimated to cost a further £10000. There was no damage to the environment.
This was an ECRA as it resulted in the loss of more than 5% of the qualifying quantity of a dangerous substance as laid out in Part 1 of Schedule 7 of the COMAH regulations.
The incident is still under investigation by the CA.
This COMAH top tier site is an integrated steelworks. On 8 November 2001 there was a major fire and explosion within Blast Furnace No 5, which destroyed its integrity and allowed an unknown quantity of extremely flammable and toxic blast furnace gas (mainly carbon monoxide) to be released.
The furnace was constructed in two sections, the top half having limited vertical movement on a lap joint with the bottom half. It had a 3.5cm thick steel outer shell and a refractory lining in which were inserted approximately 1400 copper coolers. Water was pumped through the coolers to remove the heat. The furnace was approximately 90m high and had a shallow cone profile with a maximum diameter of 12m towards the base. It was capable of containing approximately 2000 tonnes of burden (iron ore, coke, and limestone) and had 24 tuyeres (nozzles) located at the base just above the hearth. Typically, this process involves hot air being blasted into the bottom of the furnace through the tuyeres (capable of delivering 180m³ per hour of hot blast), leading to the production of several thousand tonnes of iron per day. The oxygen in the air combusts with the coke to form carbon monoxide and generates a great deal of heat. The carbon monoxide flows up through the blast furnace and removes the oxygen from the iron ores on their way down, thereby leaving iron. The heat within the furnace melts the iron and the resulting liquid iron is tapped (removed) at regular intervals by opening a hole in the bottom of the furnace and allowing it to flow out.
On the day of the incident the blast furnace operating team were experiencing problems tapping from Blast Furnace No 5. Some time earlier, an oxygen lance had been inserted into the tap hole. An explosion occurred within the furnace, sufficient to lift the top half off and beyond the lap joint. The top half of the furnace remained upright and re-located itself on the bottom half, but in an unstable state. It had rotated during the lift and was no longer seated correctly. The estimated distance of lift was between 0.5m and 0.75m. This allowed some burden, slag and molten metal (approximately 200 tonnes) and a large volume of hot blast gases to be ejected. The blast furnace gas subsequently ignited and flames enveloped the furnace for a brief period. At the time of writing, the exact cause and sequence of events leading up to the explosion is unknown.
Both on-site and off-site emergency plans were initiated and Fire, Police and Ambulance Services attended the scene. To restrict access, the Police cordoned off the furnace area. The incident resulted in 3 fatalities and 17 other injuries to employees (5 of whom were detained in hospital in intensive care, critically ill from burns and lung damage sustained by inhalation of hot gas). There was minimal disruption to the surrounding area on the night of the incident and no damage was caused to the environment.
This was an ECRA as laid out in Part 1 of schedule 7 of the COMAH regulations, as it resulted in serious danger to human health, involved one or more dangerous substances and damage to property exceeded 2 million Euros (approximately £1.4 million)
The initial investigation by the CA revealed that approximately 48 hours prior to the incident there had been problems operating Blast Furnace No 5. Cooling water had been leaking into the furnace and it had become ‘chilled’. Only 5 of the 24 tuyeres were operational, with the rest being blocked by solid material.
The incident is still under investigation by the CA.
There were 4 ECRAs in 2001/02. This is similar to the average number of major accidents reported annually under the previous CIMAH Regulations.
Whilst recognising that it is difficult to draw conclusions from such a small sample, ECRAs can be used as a crude measure of safety performance. The Accident Frequency Rate (AFR) for the period April 2001 to March 2002 is 3.6 ECRAs per thousand COMAH establishments per annum. Alternatively this can be expressed as 1 ECRA per 275 COMAH establishments per annum.
There is concern at the magnitude and frequency of these accidents and at the repeated underlying causes of major accidents. The CA will continue to use the COMAH Regulations as the vehicle for improving corporate governance of major hazard sites.
HSE is also working in partnership with the main chemical industry trade associations through the Chemical and Downstream Oil Industry Forum (CDOIF - a tripartite forum of HSE, industry and workforce representatives to discuss and set health and safety priorities and targets) to prevent major accidents and reduce the number of ECRAs by 20% by 2004, as part of the UK Revitalising Health and Safety Strategy.
This is the third annual report that has been published, giving details of EC reportable accidents in England, Wales and Scotland. The CA believes it will provide an insight into the safety performance of industry and its own performance as a regulator. It will also enable lessons to be learned from past accidents, thus helping to prevent similar accidents occurring in the future.
The CA would welcome feedback on any aspect of this report. Any comments or requests for further information should be addressed to the following contacts:
John Garraway, COMAH Policy Advisor, Environment Agency,
Block 1, Government Buildings, Burghill Road, Westbury on Trym, Bristol BS10 6EZ
John Burns, Policy Advisor, SEPA Edinburgh Office,
Heriot-Watt Research Park, Avenue North, Riccarton, Edinburgh EH14 4AP
1 The Control of Major Accident Hazards Regulations 1999, S.I. 1999 No.743,
2 ISBN 0 11 082192 0, The Stationery Office £5.80.
3 The Control of Industrial Major Accident Hazards Regulations 1984, SI 1984 No. 1902, ISBN 0 11 047902 5, The Stationary Office.
This document is located on the Internet under ‘COMAH major accidents notified to the European Commission England, Wales and Scotland 2001-2002’ and can be accessed using the following address:
Summary Details of COMAH EC Reportable Accidents 2001-2002
|Operator, location & date||Accident description & dangerous substances||Accident consequences & ECRA notification criteria||Causes and actions taken|
Release & ignition of 179 tonnes of extremely flammable hydrocarbons (a mixture of ethane, propane & butane) from the de-ethaniser column overhead pipework.
Three minor injuries: 1 to on-site personnel & 2 to members of the public. On-site personnel were evacuated from the immediate vicinity. Extensive damage to off-site homes & businesses. No damage to the environment.
Fire & loss of more than 5% of the top tier threshold inventory.
Failure of the de-ethaniser column overhead pipework due to erosion/corrosion causing release of extremely flammable hydrocarbons.
Inspection strategy for pipework. The investigation is ongoing.
Park Environmental Services Ltd,
Release of 186m3 of hydrogen sulphide gas from a 500m3 treatment tank during transfer of waste alkali solution from a road tanker.
1 fatality from asphyxiation & 3 further injuries to on-site personnel from exposure to hydrogen sulphide gas. No damage to the environment.
Serious danger to human health & involved the release of one or more dangerous substances.
Insufficient analysis of waste chemicals to determine the nature & volume of toxic gas that would be generated during processing. Evidence of inadequate maintenance, in that the tank lid had severely corroded & collapsed into tank & the extraction system was inadequate to prevent release.
Company prosecuted for three breaches of Health and Safety at Work etc Act Section 2 & a fine imposed totalling £250000.
Release of 16.10 tonnes of liquid propane during sampling from a road tanker.
1 minor injury to on-site personnel. The emergency lasted for approximately 6 hours & no damage to the environment. Damage to adjacent vehicles estimated at £5000 & inspection of interceptors using CCTV estimated at £10000.
Loss of more than 5% of the top tier threshold inventory.
Vehicle fitter attempting to drain off liquid propane for sampling in parking area at the loading terminal. Failure to close the tanker globe valve fully resulted in the spillage, which entered the surface water drains & reached the oil/water interceptors. The liquid propane flashed off but did not ignite. The pressure lifted the interceptor covers. The investigation is ongoing.
Corus (UK) Ltd,
Fire and explosion in Blast Furnace No 5 allowing an unknown quantity of extremely flammable & toxic gas (mainly carbon monoxide) to be released.
3 fatalities and 17 injured (5 were detained in hospital under intensive care, being critically ill from burns & lung damage). No damage to the environment.
Serious danger to human health & release of one or more substances. Damage to property exceeded 2 million Euros (approximately £1.4 million).
An explosion occurred in Blast Furnace No 5. The blast furnace gas subsequently ignited & flames enveloped the furnace for a short period.
The cause of this incident has not been established & the investigation is ongoing.
Regulation 21(1) and (2)
CRITERIA FOR NOTIFICATION OF A MAJOR ACCIDENT TO THE EUROPEAN COMMISSION AND INFORMATION TO BE NOTIFIED
(This part sets out the provisions of Annex VI to the Directive)
The criteria referred to in regulation 21(1) are as follows-