New Jersey’s Department of Transportation still has not determined what caused the late March collapse of a retaining wall on the massive Camden County construction project to connect Interstates 295 and 76 to Route 42.

There are some potential clues.

Heavy rain on top of high groundwater in the embankment where the wall was built, in Bellmawr, may have contributed to the March 25 incident, the state’s transportation commissioner said in a letter to a local state lawmaker last month.

The water “appears to have compromised the subsurface soil condition,” Commissioner Diane Gutierrez-Scaccetti wrote Sept. 15 to Assemblyman Bill Moen (D., Camden).

An engineering firm, Hardesty & Hanover, is working on an independent investigation of the collapse. Gutierrez-Scaccetti cautioned the precise cause can’t be fixed until the probe is done.

Residents of Bellmawr and other nearby Camden County towns, already disrupted for years by the construction of ramps and roadways for the $900 million Direct Connect project, recently expressed safety concerns after torrential rains in late summer and fall, including regional flooding caused by remnants of Hurricane Ida.

“In conversations with neighbors, the recent weather has been fresh in their minds,” Moen said in an interview. He said it’s most important that wall repairs and the remaining construction be done safely, and “we expect updates along the way.”

Prompted by those concerns, Moen wrote to Gutierrez-Scaccetti on Sept. 10 asking for an update. The exchange was first reported by the local news site 42Freeway.com, which reports on South Jersey road projects and real estate development.

» READ MORE: Retaining wall collapse in South Jersey could further delay a $900 million fix of a regional traffic nightmare

Early in the morning of March 25, workers discovered the retaining wall sagging, with some of its tiles bulging. It was built on a 30-foot embankment, made with fill material.

The elevated roadway supported by the wall was not open to traffic, and no one was injured. Eventually it will form the core of southbound I-295, carrying seven lanes toward Delaware. Now, drivers have to negotiate the death-defying Al-Jo’s curve, with its brutal merge onto Route 42, before merging again onto the southbound interstate.

Direct Connect was already several years behind schedule. Construction began in summer 2013 and is expected to be complete in 2028. It was initially scheduled to be finished this year.