It was commissioned in 1953 and had a maximum processing capacity of 11 million tonnes of crude oil per year.
Further up the Medway at Kingsnorth, Berry Wiggins and Company started constructing an oil refinery and tank farm in 1930.
[5][6] Towards the south-east of the site the ground level was increased with six feet (1.8 m) of compacted sand, dredged from the sea.
[5] Six thousand concrete piles provided the foundations of major plant and equipment on the marshy soil.
[5] A bay on the Saltpan Reach of the River Medway was enclosed to provide a storage reservoir for cooling water, this filled on the rising tide.
[6][5] In 1952 the Thames to Grain (T/G) pipeline was recommissioned to carry refined fuel from the BP Kent refinery to the Walton storage depot.
This led to the need to install new pumping units and to construct a new pump-station at Stoke (TQ851757), located close to the Isle of Grain refinery.
[9] The first tanker containing 27,000 tonnes of crude oil from the Middle East arrived at the refinery in October 1952.
[11] Crude oil mainly came from the Middle East with smaller amounts from Libya, Nigeria and South America.
[14] A petrochemical plant to manufacture synthetic fibres, a joint venture by BP and California Chemicals known as BP-California Ltd, was planned and constructed from 1960.
[10] Intermediate products from the refinery processes included: straight run blending components; isopentane; propane; butane; aviation alkylate; heavy alkylate; thermal reformate; aviation extract; Udex raffinate; aviation platformate; total platformate; heavy platformate; aviation fuel (ATG); acid washed kero; sweetened kero; kero raffinate; kero extract; light cat-cracker spirit; heavy cat-cracker spirit desulphurised gas oil; straight run gas oil; fuel oil blending components; extracts, lubricating oils.
[18] The refinery provided local employment opportunities; prior to its construction many people were working on farms at very low wages.
[19] The principal products from the refinery were:[10] The rising price of oil in the 1970s resulted in a slump in consumption, which meant there was a considerable excess of refining capacity throughout Europe.
At its maximum extent the refinery and its tank farm covered a site of four square kilometres (400 hectares).