Efforts to redevelop the Centennial Mills site on the bank of the Willamette River in Northwest Portland have once again ended in failure.

On April 17, Kimberly Branam, the executive director of Prosper Portland, the city’s economic development agency, informed City Council via email that Lynd Opportunity Partners, which Branam’s agency last year selected as the latest developer of the troubled site, was backing out of its deal with the city.

The city acquired the four-acre site in 2000 and hoped to preserve and redevelop what had been an active grain mill and dock since 1910. The property offered an opportunity to extend the riverfront greenway trail for recreational use and to re-claim for mixed commercial uses part of Portland’s industrial and shipping heritage.

But the mill’s waterfront location, the cost of cleaning up the site and the cost of preserving the decrepit structure defeated two earlier developers, California-based LAB Holdings (2006) and Portland-based Harsch Investment Properties (2013), both of which inked deals to tackle Centennial Mills, only to later walk away.

Now, it’s happened a third time.

“Last week Lynd representatives declined to submit a revised letter of interest on the property, citing concerns about their ability to deliver a project that met the city’s requirements and expectations,” Branam wrote. “Since making their initial offer that formed the basis for their selection, both Lynd’s development program and financial terms had changed significantly. Key challenges included:

“Cost of renovation and reuse of the Flour Mill and mixed support for partial remnant concept; Cost of environmental remediation; and Waterfront development constraints and complexity of regulations.”

Prosper Portland documents show the agency has spent at least $27 million on the site so far, including the initial acquisition and subsequent site work, according to agency documents. Much of that money was spent on demolishing some of the original mill structure in 2015 and 2016.

In her email, Branam told city commissioners the next step will be to reengage with companies that have previously expressed interest in the site.

“Prosper Portland received considerable interest from the development community in its initial solicitation for offers,” Branam said. “We are planning to reengage with the community and potential development partners to determine a path forward and shared vision for success at Centennial Mills.”

Eileen Park, a spokeswoman for Mayor Ted Wheeler said in a statement that the city will continue to pursue a solution for the property.

“We’ve known for a long time that this site presents unique challenges and opportunities,” Park said. “We’re disappointed the Lynd team didn’t see a path forward, but we appreciate their efforts. We remain committed to finding the right partner and delivering a project that increases access to the river and meets the development needs of our growing city.”