Sixty-five former construction workers filed a 1.37 billion yen lawsuit Wednesday against the government and general contractors for lung disease they claim they developed while digging tunnels for public works projects.

The suits were brought before the district courts of Nagano, Tokushima and Matsuyama, Ehime Prefecture, and are part of a series of legal actions against the government that began last November after damages suits against general contractors made progress toward settlement.

Similar cases have been filed in Tokyo, Sapporo, Sendai, Niigata and Kumamoto. Another suit is planned for Monday in Kanazawa, Ishikawa Prefecture, according to the All Japan Construction, Transport and General Workers' Union, which is in charge of organizing them.

Of the 65 plaintiffs who developed pneumoconiosis, caused by long-term inhalation of irritants, 26 have settled with general contractors and are demanding the government pay them 3.3 million yen each. The other 39 are demanding the government and contractors pay them 33 million yen each, the Tokyo-based union said.

They argue that the government, as the initiator of the projects, is responsible for ensuring the safety of workers and is obliged by the Pneumoconiosis Law to oversee contractors.

The plaintiffs also plan to seek a thorough review of the government's pneumoconiosis measures and creation of a fund to help victims, according to their claim.

Kazuyoshi Otsuka, one of the plaintiffs, said he could not suppress his anger over the government's inaction.

"Anger wells up inside me when I wonder why the government cannot regulate (airborne irritants)," the 71-year-old man from Ehime Prefecture said.