Marler said he saw leaks and openings animals could crawl into while touring the plant.
State inspectors had found dead rodents in the plant shortly after it closed down Feb. 9.
Marler toured the plant Wednesday with several experts, mainly looking at the structure of the plant, in relation to his lawsuits.
The Associated Press reported the company's bankruptcy lawyer didn't immediately return a call on Wednesday.
The latest news from around North Texas.
On Thursday, Marler will tour the company's plant in Blakely, Ga., which was at the heart of the salmonella outbreak that sickened hundreds and was linked to the deaths of at least nine people.
State inspectors who searched the Georgia plant in October found only minor problems, but less than three months later federal agents found roaches, mold, a leaking roof and other problems. That plant was also shut down after the outbreak. Peanut Corp., which is based in Lynchburg, Va., has since filed for bankruptcy.
Marler said that he was especially interested in the Blakely plant because he said it's "pretty clear" the contamination occurred in Georgia and those peanuts were then shipped to Texas. He said he'll be looking at the quality of the roaster at the Blakely plant.
"Did the peanuts come in contaminated and did the roasting not kill it? Or were they recontaminated after they were roasted? Are we able to say at what point the contamination occurred?" he said.
Marler, a Seattle-based foodborne illness attorney who represents about 80 victims of the salmonella outbreak, said the condition of the Plainview plant was not as bad as he thought it might be. He said spending some money spent on roofing and vermin control would probably get the facility back in working order.
Peanut Corp. was fined $14.6 million earlier this month by Texas regulators.
Copyright AP - Associated Press