In the petition, the firm said it's representing three people severely injured in the Aug. 1 collapse and the families of two people who died in the disaster. It did not identify the victims, and attorney James Schwebel declined to reveal them.

A hearing on the petition was scheduled for 2 p.m. Wednesday before U.S. District Judge Patrick J. Schiltz in St. Paul.

"We are in the very preliminary stage on this," Schwebel said. "We've been retained by several families. We've been contacted by many others. They're obviously wanting to make sure there is some accountability for whoever is culpable for this disaster, and we need to have experts to answer many of these questions for us."

Copies of the petition were served on the offices of the U.S. attorney for Minnesota, the Minneapolis city attorney and the state attorney general because federal, city and state and city agencies are involved in the collapse investigation. Spokespeople for those offices did not immediately return phone calls Tuesday.

The petition said the firm had hired two experts to help it pursue wrongful death and personal injury lawsuits on behalf of its clients, and that they had special training and experience that would "assist a jury in determining negligence and causation issues."

Time is of the essence because the impending dismantling of the wreckage "will forever make it impossible to perform an inspection on the site," the petition said.

Nine people were confirmed dead and four were still missing as of Tuesday, while about 100 people were injured in the collapse.

Wrongful death lawsuits must be filed in three years, but the deadline for negligence suits is longer, Schwebel said.

The state's liability is limited to $1 million, but any lawsuits could also target private contractors and their insurers.