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Advisory Council on the Environment

 

Styrene Spillage Incident on 5 February 2000

(ACE Paper 09/2000)
For information

Background

On 5 February 2000, a licensed Category 5 DG tank wagon laden with 22 tonnes of styrene overturned whilst travelling along Fuk Hi Street on its way to a chemical plant at Yuen Long Industrial Estate. As a result, about 15 tonnes of styrene spilt out from the ruptured tank and flowed into the sewer underneath the roadway. Photographs showing the overturned vehicle and the ruptured tank are enclosed at the Annex to this paper.

2.Styrene is a colourless oily liquid, irritant to eye and skin. It is highly volatile and floats over water. It has a flash point of about 32? and is classified as a Category 5, Class 2 dangerous goods (DG) under the Dangerous Goods Ordinance (DGO), Chapter 295 of the Laws of Hong Kong.

3.In accordance with Section 6 of the DGO, the storage, use or conveyance of styrene in any quantity exceeding 20 litres is subject to the licensing control of the Fire Services Department (FSD).

4.The accident has aroused widespread public concern over the subsequent environmental impact on the ecosystems and the associated wildlife in Inner Deep Bay and the Mai Po Wetland. This Paper seeks to inform Members of the incident, the actions taken by FSD and the planned amendments to the DGO to reduce the probability of similar mishap from recurring.

Actions Taken by FSD

5.The incident was initially reported as an emergency ambulance call requesting ambulance service for the driver of the tank wagon who had sustained minor injury as a result of accident. Upon arrival, the ambulance crews discovered the spillage of styrene. They immediately reported the incident to the Fire Services Communication Centre. Consequently, a total of 8 fire appliances with 40 FSD operational crews of various ranks turned out to tackle the spillage.

6.The immediate vicinity of the incident was cordoned off. On the advice of the Government Chemist, the operational crews applied about 100 kg of chemical absorbent to the affected roadway to absorb the spilt styrene. Furthermore, as a quantity of styrene had flowed into the underground sewer, copious amount of water was also applied to the sewer to dilute the concentration of flammable vapour for the purpose of preventing any possible ignition.

7.About 7 tonnes of styrene remaining inside the unaffected compartments of the ruptured tank were transferred to another licensed Category 5 DG tank wagon for removal from the scene in the presence of FSD operational crews.

8.Officers of the Environmental Protection Department were also in attendance at the incident. They inspected the affected water courses and collected water samples from Yuen Long Industrial Estate Nullah, Fairview Park Nullah, Shenzhen River, Deep Bay off Lau Fau Shan and Mai Po Marsh that night and the next day. The concentrations of styrene in the samples ranged from 0.41 mg/litre (11 hrs after the incident) to 0.025 - 0.032 mg/litre (24 hrs after the incident). According to overseas research, styrene is moderately toxic to aquatic life, with a relatively low risk for bioaccumulation. It is not a very soluble substance, lighter than water, highly volatile, evaporates rapidly, and is biodegradable. The chemical thus should decline to very low levels rapidly. The test results confirm that the level of styrene in water has decreased rapidly within a short period of time to well below the toxic level. In view of the above and the fact that fish continued to swim in the nullahs and Shan Pui River without further death, it was concluded that there should not be further impact to the environment.

9.Despite the fact that the spillage of styrene was resulted from a traffic accident, FSD is exploring jointly with the Department of Justice the possibility of instituting legal action against the driver of the tank wagon under Regulation 133 of the Dangerous Goods (General) Regulations in order to give the necessary deterrent effect.

Proposed Amendments to DGO

10.In the wake of the cyanide spillage incident which occurred at Tai Po Road in late 1997, FSD completed an overall review of the DGO in 1998 and came up with a package of proposed amendments to the DGO for tightening the control over the storage, manufacture and conveyance of DG. These proposals have been incorporated in the Dangerous Goods (Amendment) Bill 1999, which is now being scrutinized by the Legislative Council.

11.In a nutshell, FSD proposes that the provisions for classification, labelling and packaging of DG should follow the International Maritime Dangerous Goods Code, which is generally adopted as the basis of domestic rules on DG shipment by our trading partners. In this regard, the DG to be regulated would be expanded from the present 400 plus DG to about 1600 types.

12.As regards the provisions dedicated to regulate the conveyance of DG by vehicles, FSD proposes that the existing licensing regime for DG in Categories 1, 2 and 5 should be extended to cover all other Categories. Furthermore, FSD also proposes to introduce a mandatory training scheme for all DG vehicle drivers to equip them with adequate knowledge and skill on the proper practices and emergency procedures in the handling of DG. Specifically, they would be trained on the risk associated with DG, the related legislative requirements, the safety provisions on board the DG vehicles and the procedures to be taken in the event of an emergency. Moreover, the training course would also include a practical session on the use of emergency equipment, such as fire extinguishers, respirators and waste disposal drums.

13.Additionally, FSD also proposes to require the consignors of DG to issue a transport document to the operators of DG vehicles, providing details on the classification and quantity of the DG carried and the proper emergency procedures to be followed. They will also be required to issue a written declaration confirming that the DG have been properly packed. Such document and declaration are required to be passed to the DG vehicle drivers and thence the consignees together with the goods.

Way Forward

14.The styrene spillage incident revealed the lack of adequate safety awareness and failure to adopt the proper emergency procedures on the part of the driver. It also reinforced the need to implement a mandatory training scheme for DG vehicle drivers. FSD is now working in collaboration with the Occupational Safety and Health Council, Vocational Training Council, the oil industry and the gas suppliers on the details of the training programme.

15.It is envisaged that the Dangerous Goods (Amendment) Bill 1999 will be enacted in the current legislative session and that a grace period of not more than 2 years will be given for the implementation of the DG vehicle driver training scheme.

16.Members are invited to note the contents of this paper and welcomed to offer views, if any, on the subject. Consolidated views will be passed to the Dangerous Goods Standing Committee for reference and consideration.

Fire Services Department
March 2000

 

 

 

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