SALEM, Ore. (AP) -- The founder and CEO of Sunwest Management has filed a personal bankruptcy in an effort to halt the collapse of his senior-housing empire.

Jon Harder, 41, of Salem faces between $1.2 billion and $1.8 billion in debt, much of it corporate obligations the Salem man personally guaranteed, The Oregonian newspaper reported.

Harder built Sunwest into the nation's fourth-largest senior housing provider. At its peak, Sunwest had about 300 assisted living and retirement centers.

But the company and its affiliates used a massive amount of debt to fuel the expansion. And now, lawyers say, Sunwest can't pay it back, especially with many retirement homes now valued at less than the debt owned on them.

Lawyers for Harder say they hope that his bankruptcy will allow a broader restructuring of his company. "Given the catastrophic condition of the real estate market, we felt that the best chance for a fair and intelligent workout was to get all the legal and financial battles under one umbrella," said Steve English, a Portland lawyer.

Harder seeks to pay all Sunwest's creditors -- lenders, vendors and investors -- in full, according to court documents. Harder said he will take a subordinate position to his creditors, meaning he will get paid last.

Sunwest is seeking an immediate stay that would temporarily halt a number of lawsuits and foreclosure actions filed by creditors.

Absent Harder's bankruptcy, Sunwest's lenders would continue to close in and take control of one retirement community at a time. The company has already lost more than 30 retirement homes to foreclosure or receivership and could lose triple that number to pending actions.

With Sunwest confronting a dire financial situation, concerns have been raised that the quality of care is diminishing. Since summer, Sunwest has been sanctioned by Oregon regulators for sanitation problems, drug dosage errors and other issues.

In court papers, Sunwest acknowledged that the continuing cycle of foreclosures and other activities by lenders could put Sunwest's residents at risk.