NASHVILLE, Tenn. -- The controversial practice of dumping low-level radioactive waste in Tennessee is kicking up dust in California.

Video: Lawmaker: Companies Use Loophole To Dump Radioactive Waste

Twelve state senators in California said companies are skirting the strict disposal rules in their state and Tennessee is helping them do it.

The senators call it the "Tennessee Loophole," and they want it closed up tight.

A building is all that’s left of ICN Radiopharmaceuticals -- a California medical company that used radioactive material.

The doors aren't the only thing locked up tight. The information about potential contamination near houses and a busy shopping center nearby are also locked away.

A local newspaper’s request for more information was denied in light of homeland security concerns after the Sept. 11, 2001, terrorist attacks.

But a dozen California state senators said they know where the company’s dirt and material contaminated with radioactive Carbon 14 ended up: Studsvik Race, a Memphis nuclear processing facility that routinely dumps its processed material into a Shelby County landfill.

“If it’s (a) problem, why did Tennessee say bring it here? Because it’s safe,” said Eddie Nanney of the Tennessee Radiological Health Department.

“Obviously, some of it has to go to a licensed site. The lower waste could be approved on a case by case basis to go to a landfill, and that typically is done all across the country,” he said.

But officials said the practice was not done in California.

Companies said that Tennessee is a willing partner.

Shiela Kuehl is one of the 12 state senators pushing for an audit in California. They have launched a full investigation of who is skirting the strict 5-year-old moratorium on dumping anything radioactive in ordinary landfills.

“In California, we do not ship low-level radioactive waste legally into any municipal landfills,” she said.

“Our entities in California are trying to get around this moratorium by sending all this waste out of state. I frankly think Tennessee ought to be somewhat alarmed,” she said.

Officials and residents in Murfreesboro are alarmed.

Tuesday night, county commissioners called for an end to radioactive dumping at Middle Point landfill. This is where some of the 10 million pounds of radioactive waste was taken in two years ago.

The waste came from the dismantled Big Rock Point nuclear plant in Michigan.

“The audit, I hope, will be quite thorough, and we’ll know a lot more about what we now only suspect,” Kuehl said.

“I think making Tennessee a dumping ground for our low-level radioactive waste is unconscionable,” she said.

The California lawmakers said they also want to know who adopted a brand new classification for slightly radioactive waste.

They said that choice of words may be justifying a lot of the decisions made on the west coast and in Tennessee.

Channel 4 News continues to ask where the low-level radioactive waste at Middle Point Landfill is coming from.

Both companies, Toxco and Impact, have refused requests for information. They said they would not share information about their clients.