This advice is designed to provide basic guidance to traders. It is not a complete or authoritative statement of the law.
Where any underground petrol tank or compartment is permanently taken out of use it must be rendered safe by one of the following methods:
Tanks to be abandoned in place
Any tank to be abandoned in place should be rendered safe
1. by filling with cement slurry using the following procedure.
2. by the use of RG22 HYDROPHOBIC HARD FOAM. This is a specialist process and can only be undertaken by an appointed contractor.
Any tank to be removed should be rendered safe before excavation work starts.
For a tank without leaks the following initial procedure should be followed
Excavation work should be carried out with the tank in the filled condition and with suitable precautions to avoid sparks. When the tank is ready for lifting any water used should be emptied and all openings immediately closed. Water should be disposed of by a hazardous waster disposal contractor.
Alternatively the tank may be rendered gas free by the internal application of an inert gas by a competent person.
For a tank with leaks, all residual petrol should be removed, and the tank ‘bottomed out’ (see paras 1(a) and 1(b) above) and the atmosphere in the tank inerted by means of carbon dioxide, nitrogen or nitrogen foam. (See guidance on these inerting methods in HSE Guidance Notes CS 15). Inerting should be maintained during the excavation process any fault in the tank shell should be sealed as soon as it is exposed and the atmosphere in the excavation should be monitored throughout the process in case of leakage of inert gas or of the presence of a flammable atmosphere arising from petrol leakage.
Any excavated tank should be indelibly marked on two sides with the words PETROL - HIGHLY FLAMMABLE in letters not less than 50mm high and should be water filled or remain inerted, as appropriate, pending disposal.
Any tank which has been removed from its excavation should be disposed of safety as soon as possible. Preparation for and removal by road should be in accordance with the provisions of the current legislation in force at the time.
The person responsible for removal of a tank from a filling station should ensure that the recipient of the tank is made aware of the tank’s previous use and of the need to take adequate precautions against fires and explosions when dealing with it.
Cleaning or demolition of any tank on site should not take place without the agreement of the appropriate authority.
The location of any abandoned tank should be recorded in the site register and brought to the attention of any person who subsequently becomes responsible for the site.
Further the Trading Standards Service should be made aware of the final destination of any tank which has been removed from the ground.
The tank may be used for the storage of diesel or gas oil providing the petrol tank has had all residual of petrol removed from it, and been ‘bottomed out’ (which involves the removal of that quantity of petrol and deposits which remain below the pump suction pipeline, using a hand pump or a flame-proof electrical pump.) This procedure should be performed by a specialist contractor.
The tank must be filled totally in order to dispel any petroleum vapour. It is important to remember to drain down the pump and pipelines thereby removing all petrol before introducing an alternative fuel.
The Petroleum Officer of the Trading Standards Service must be advised on which course of action it is proposed to take to render a decommissioned tank safe and have the opportunity to be in attendance when tanks are filled.
For further details please contact your local Trading Standards Office.
120897 ISS 1.
Reviewed November 2010
B/pet/047/003 November 2002