Members of Osaka Mayor Toru Hashimoto’s local party, Osaka Ishin no Kai, and New Komeito, which form the ruling coalition in the municipal assembly, voted against an ordinance proposal Monday that would have clarified the city’s financial responsibilities in the event of health problems created by incinerating tainted debris from Tohoku.

The ordinance had been sought by local residents and assembly members opposed to the burning of 6,000 tons of quake debris from Iwate Prefecture, which is scheduled to be incinerated by the end of the current fiscal year, which ends in March.

The city and Osaka Prefecture, which agreed to accept the debris, say radiation levels in the debris are minuscule, and well below the minimum safety standards. On Feb. 1, incineration of the debris began on Maishima, an artificial island in the harbor district.

Osaka officials say the plan is to burn about 100 tons of debris per day and to use the ashes as landfill on the nearby man-made island of Yumeshima. But since the plan was announced last summer, local residents, as well as ruling Liberal Democratic Party and other opposition parties, including the Japanese Communist Party, have all expressed concern, and pushed for an ordinance to stop Hashimoto and the ruling parties from using Osaka as a repository for the debris.

“There is a huge cost involved in transporting the debris all the way from Iwate to Osaka. And it’s not entirely clear who will take financial responsibility for disposing of the waste, or for potential health problems down the line. I’ve never heard Hashimoto say he would take responsibility if something went wrong,” Taeko Kitano, LDP policy chief for the municipal assembly, said.

Osaka has also promised to accept another 30,000 tons of debris for local disposal during the fiscal 2013. But the city has yet to approve a budget for that, and a tough fight between municipal assembly proponents and opponents of accepting the debris is expected.

Other local residents, meanwhile, continue to take separate measures to halt the burning and burial of the debris. Late last month, 260 residents in Osaka and neighboring Hyogo filed a class-action lawsuit against the prefecture and city in Osaka District Court seeking to halt the transportation, incineration and burial of Iwate debris.

The lawsuit cited concerns the city’s plan would lead to the spread of large quantities of radioactive material in the surrounding air and seawater. Osaka Gov. Ichiro Matsui, in reply to the suit, said experts had scientifically judged there would be no health damage.