3069 Guidance on the declassification of tanks previously in leaded gasoline service

Overview:

At present, it is common oil industry practice to consider all tankage that has contained leaded gasoline to be classified as a leaded tank for its lifetime, i.e. until final dismantling. The phrase 'once in leaded service always in leaded service' has been applied even to tanks which have not been used to store leaded gasoline for a number of years and have been in alternative service. The large scale move to unleaded gasoline and away from leaded gasoline has freed large numbers of storage tanks for alternative service. Hitherto, work on such tanks has been controlled as if the tanks contained leaded product, which places considerable constraint on subsequent operations and imposes ongoing cost penalties. It is therefore considered opportune to introduce a procedure whereby, following a formal programme of cleaning, testing, and risk assessment, these tanks can, where appropriate, be declassified from the status of 'leaded tank'.

This procedure defines a test protocol for evaluating exposure to lead resulting from previous contamination from organic lead gasoline additives. It includes what is in effect a worst-case simulation of hot work, which could make the lead airborne in the form of organic lead vapour and inorganic lead fume, and an assessment of the lead content of the scale (see Annex C).

This document therefore advises on procedures for the declassification of bulk motor gasoline tanks used for refining and distribution which were formerly in leaded gasoline service. If these procedures are applied, then the potential for significant occupational exposure to organic and inorganic lead during work on the tank, is greatly reduced. The guidance goes beyond existing procedures for decontaminating leaded gasoline tanks (see EI Model code of safe practice part 16: Tank cleaning safety code and API RP 2016) and applies to all internal operations including flame cutting and welding. The declassification continues for the remaining service life of the tank in respect of occupational exposure to lead arising from the prior leaded service, but does not apply to exposures arising from the lead content of any paint, or to the disposal of potentially contaminated waste. (Subject to there being nochange in exposure standards for organic or inorganic lead-in-air.)