Philadelphia Energy Solutions' (PES) 335,000 barrel-per-day (bpd) oil refining complex, the largest and oldest on the US East Coast, is set to permanently shut down after it was hit by a devastating fire on June 21.

Benchmark US gasoline refining margins have gained over 16% since the fire at the plant which supplies around 55,000 bpd of gasoline to the region, according to consultancy Energy Aspects.

Gasoline stocks in the US East Coast, also known as PADD1, dropped last week by 2.327 million barrels, according to data from the Energy Information Administration.

As a result, the economics for shipping gasoline from Europe to the US East Coast improved significantly in recent days, traders said.

A sharp rise in tanker freight rates is, however, weighing on the arbitrage, the traders said.

Around 18 tankers carrying a gasoline cargo of 37,000 tonnes, totalling 666,000 tonnes, or 5.62 million barrels, have been booked out of Europe on the transatlantic route in the first 10 days of July, according to shipping data obtained by Reuters.

A 60,000 tonne cargo of naphtha, used as a gasoline blending component, was also provisionally booked out of the Baltic port of Ust Luga to go on the transatlantic route, according to the data.

Refinitiv Eikon data shows that Europe sent 850,000 tonnes of gasoline to the US East Coast throughout the entire month of June, and 1.63 million tonnes in May.

Europe has traditionally supplied large volumes of gasoline to the US East Coast, but the flow on the transatlantic route decreased in recent years as US domestic production rose.