Toyota Motor Corp. expects to delay delivery of about 23,000 vehicles by up to a month while it cleans up soot from a Nippon Steel & Sumitomo Metal Corp. plant in Aichi Prefecture.

The automaker said Wednesday that around 20,000 vehicles bound for export and some 3,000 for the domestic market at two storage sites in the city of Tokai were covered in black soot emitted from the steel mill late last month.

The export vehicles could be delayed by one week to one month, while the domestic vehicles are likely to head out by as much as three weeks late.

A Toyota official said the company has not decided whether to seek compensation from Nippon Steel.

Toyota mobilized about 5,000 employees from its factory to clean the vehicles for export while local dealers are removing the soot from the cars to be sold in Japan.

A power failure June 22 at the Nagoya steelworks' coke oven forced Nippon Steel to burn gas containing carbon monoxide, causing the emission of huge plumes of black smoke.

The power supply at the mill shut down due to errors in an operating manual.