The price of US crude oil for June delivery almost halved on Tuesday and Brent, the international benchmark, dropped below $20 per barrel for the first time in 18 years, as global oil markets remained under intense pressure. The value of West Texas Intermediate for delivery in June – which had held above $20 a barrel on Monday even as the May contract traded at a historically unprecedented negative price – slumped to $6.50 at its worst, before recovering to settle at $11.57, down 43 percent.

The move suggested the blowout in the May contract was more than just a technical blip, and reflected growing concern that US storage facilities will fill up unless energy demand quickly rebounds from its coronavirus-related collapse. Brent crude, meanwhile, extended its fall in afternoon trading in New York, touching a fresh low of $17.51 a barrel before recovering slightly to settle at $19.33 a barrel, down 24 percent on the day.

“The car is speeding up and market forces will inflict further pain until either we hit rock bottom, or Covid clears, whichever comes first,” said Michael Tran, commodity strategist at RBC Capital Markets. Coronavirus has sent the oil sector into a state of crisis, with lockdowns and travel bans implemented by authorities slashing global demand for crude by as much as a third this month from pre-crisis levels.

The severe drop in demand coincides with levels of US production remaining robust despite oil storage tanks being just weeks away from reaching capacity. The plunge to below $0 was in part the result of traders seeking to offload any obligations to take on physical product ahead of the May contract’s expiry on Tuesday, as storage reached capacity at its delivery point in Cushing, Oklahoma.

The May contracts tumbled as low as minus $40 a barrel on Monday, marking the first time it had fallen into negative territory, where it remained on Tuesday before rising to settle at $10.01 a barrel. “The contagion has spilled over to WTI June 2020 deliveries, which could also be well on their way into the red as we move towards physical delivery dates,” said Louise Dickson at Rystad Energy.