helium cliff: an anticipated decline in the supply of helium, an inert gas that is essential for magnetic resonance imaging equipment.

Roughly 30% of the world’s supply of helium is used to chill equipment such as the superconducting magnets inside MRI scanners. In the United States alone, those machines help diagnose cancer and other diseases in about 30 million procedures each year. So the impending closure of the U.S. Federal Helium Reserve, a porous rock formation in Texas that provides more than a third of the world’s helium, sparked panic last year.

The crisis was averted with just days to spare. On Oct. 2, President Obama signed the Helium Stewardship Act of 2013, allowing the reserve to continue selling its helium for a few more years. During that time, new production capacity in Qatar and Russia is slated to open to help meet the shortfall. As the reserve winds down, users will be affected. The growing reliance on commercial providers that charge more than the U.S. government may raise helium costs by 30% next year, says Richard H. Clarke, a resources consultant in Oxford, England. Installing equipment to conserve and recycle helium may increase the capital costs of scanners, but it is an essential investment to guard against ballooning helium prices.