Cushing, Oklahoma, usually stores about 40 million barrels of oil and has a capacity to carry up to 75 million. However, Cushing is holding just over half that amount as it reports a current inventory of 21.6 million barrels, according to the US Energy Information Administration.
"We're raising alarm bells right now," American Petroleum Institute CEO Mike Sommers told CNN. "We're getting to levels where we are starting to be concerned."
CNN noted that Cushing is "dangerously close to operational stress levels" and close to reaching a "tipping point" where it can no longer supply oil to all of its customers.
When Cushing's oil inventories drop below 20 million barrels, they can "effectively" hit empty, according to CNN. That can have ripple effects on the economy, as America's benchmark West Texas Intermediate oil is priced and warehoused in Cushing.
"Like blood pressure in the human body, the issue is circulation," Natasha Kaneva, the head of commodities strategy at JPMorgan, told CNN. "The system does not fail because oil disappears. It fails because the circulation network no longer has enough working volume."
The effects won't just be felt domestically. Cushing's dwindling supplies will hit the world oil market. CNN reported that unless the Strait of Hormuz opens "very soon," everyone will see what those impacts entail.