Frack waste can also be radioactive.  There is plenty of information on the web.
Here is a good place to start.

Watch out for explosive fracking pipes on the side of the highway, at rest areas or other places where scrap fracking waste isn’t supposed to be.

That’s the message the Colorado Department of Transportation sent out to its employees, followed by warnings issued by the city of Loveland, Windsor-Severance Fire Rescue and other local governments.

“It has come to our attention that recycling businesses and landfills in Colorado are turning away customers who are trying to recycle and dispose of fracking pipe,” said a memo sent by the Loveland Fire Department to city employees.

“Fracking pipe is commonly used in Colorado oil/gas wells and contains explosive charges to perforate the tubing in the wells,” the memo said. “Sometimes these explosive charges do not detonate and are still ‘live’ within the pipe; therefore fracking pipe is considered to be extremely dangerous and should not be handled by any city employees.”

Loveland safety coordinator Jacob Payne said no fracking pipes have turned up in the city yet.

CDOT recently issued a safety and risk analysis to its workers to ensure they know what the pipes look like and that they could have unexploded charges in them, should the pipes turn up along a highway right-of-way, CDOT spokeswoman Amy Ford said.

CDOT employees have not yet encountered such a pipe on any state right-of-way, she said.

Dan Garvin, owner of Colorado Iron and Metal in Fort Collins, said he received notice from the steel mills he works with to reject all fracking waste. He receives scrap steel from many oil and gas producing states, and he’s concerned about the possibility that a fracking pipe could explode on his property.

“What’s going to trigger an explosion?” he said. “Is it going to be compression? Or is it a spark?”

He said he received a memo from Nucor Steel, which owns several large metal scrap yards across the country, outlining the dangers of fracking pipes and announcing that Nucor will not accept fracking pipes into its scrap stream.

Nucor’s memo says the company has encountered two different kinds of fracking pipes, including a “perforating gun,” used to punch holes in the second kind of pipe, called production tubing.

The guns have indentations in a spiral pattern along the length of the pipe. The indentations are where charges are loaded into the tube and fire a ball bearing through the wall of the production tubing.

“Frac pipe … is considered to be potentially dangerous in the fact that no one can totally ensure that all explosive devices or substances contained within these items are fully detonated,” the memo says.

Northern Colorado landfills, including the Waste Management landfill in Ault and the Larimer County Landfill have not received any fracking pipes, officials there said.