Toyota has been forced to halt production at six factories in Japan due to a supply issue. The automaker’s plants will be down until at least Wednesday due to an explosion at one of its suppliers’ factories.

The production slowdown has been prompted by an incident at a Chuo Spring Company factory in the city of Toyota, in Aichi prefecture. The explosion occurred on Monday afternoon, injuring two workers, one in his 30s, and the other in his 40s. One of the men was taken to hospital for treatment.

The blast happened in the factory’s drying furnace, which cools hot steel, reports Nikkei. The cause of the accident is still being investigated, Chuo Spring said.

Read: Toyota ‘Glitch’ Causes Total Production Shutdown In Japan

 Explosion At Supplier Factory Causes Toyota To Pause Production At Six Japanese Plants

In total, the automaker will pause 10 production lines at six factories due to a lack of springs for its vehicles’ suspensions. Toyota does not yet know precisely when it will be able to resume production at all of the facilities.

Toyota operates a total of 14 assembly factories across Japan, which produce vehicles for both the domestic and international markets. The lines affected by this slowdown produce a range of popular vehicles, including the RAV4 and the Land Cruiser.

The incident has pointed out vulnerabilities in Toyota’s production network. Like others, the automaker employs an on-time supply network, which seeks to have parts arrive just as they’re needed. Although the strategy helps cut costs, it also means that plants have little to no surplus parts, which can lead to production pauses such as this one.

For example, production at all 14 of Toyota’s Japanese plants was halted last year, when one of its suppliers was the victim of a cyberattack. Its facilities were once again stopped in August of this year, due to a glitch in the parts ordering system.

 Explosion At Supplier Factory Causes Toyota To Pause Production At Six Japanese Plants