Western Digital Corp. and manufacturing partner Kioxia Corp. said that contamination of materials used in flash-memory chip production has hurt output at two factories in Japan.

The two companies, whose partnership is one of the largest producers of the flash memory that provides storage in phones and computers, said they’re working to get the plants in Yokkaichi, Mie Prefecture, and Kitakami, Iwate Prefecture, back to normal operations as quickly as possible. They didn’t identify the cause or provide an estimate for when that would be.

The announcement is another setback at a time when the global semiconductor supply chain has failed to keep up with a surge in demand, causing shortages that are hobbling industries across the economy. Flash memory is an essential component of many electronic devices, where it’s replaced magnetic disks as the main storage of data. Everything from Apple Inc.’s iPhones to electric cars and supercomputers relies on the chips.