Toyo Tire & Rubber Co. confirmed Tuesday that 90 more buildings have been built with its substandard earthquake shock absorption devices, bringing the total to 145.
The Osaka-based company said four employees might have been involved in falsifying performance data on the quake-absorbing rubber equipment, revealing the prospect of organizational involvement in the snowballing scandal.
The scandal broke in March when the government withdrew certification for Toyo Tire's seismic isolation products because they did not meet the requirements for quelling earthquake shocks.
In March, Toyo Tire said the devices had been used in 55 buildings in 18 of the 47 prefectures. The 90 buildings added on Tuesday are in 25 prefectures and include schools, hospitals, municipal buildings and housing complexes, according to the infrastructure ministry.
Of the 90 new buildings, 13 are in Aichi, followed by 12 in Shizuoka, 11 in Tokyo and nine in Koichi. The structures include Osaka City Central Public Hall, which is designated as a cultural asset of national importance.
Toyo Tire also said the performance of the quake-absorbing devices installed in nine other buildings could not be determined because of insufficient data.
Toyo Tire said it will examine the buildings' ability to resist quakes registering upper 6 or 7 on the seven-level Japanese seismic intensity scale in the near future and replace all defective products with new ones.
The company had been shipping the substandard devices since April 1996.
"We take this situation very seriously," Tetsuya Kuze, a senior Toyo Tire official, said at a news conference, adding the company will do its utmost to address the problem.
The company plans to announce punitive measures in early May for the employees involved in the data falsification, as well as preventive steps after confirming the findings of an investigation being carried out by a third-party law firm.