SIOUX FALLS, S.D. (KELO) — Days after an explosion rattled homes on the west side of Sioux Falls many people are still wondering exactly what happened. As we told you earlier this week, sheriff’s deputies investigated the source of the explosion after hundreds of people called 911 last Saturday.

The explosion took place outside the city limits. It was caused by what the ATF refers to as binary explosives more commonly known as Tannerite.

“911 lines lit up, we were getting calls from everywhere from towards the airport to Howard Wood Stadium to southwest Sioux Falls, so it almost came, the sound of it came almost into the center part of the city,” said Minnehaha County Sheriff Mike Milstead.

Milstead says deputies tracked down the source of the explosion and talked with the landowner.

“They were using some Tannerite binary explosive to try to take down a tree, they were unsuccessful but it was loud,” said Milstead.

Binary explosives are legal and are often sold for target practice. Milstead says if used correctly they are safe and quite frankly fun, but…

“It can be very dangerous when used in large amounts,” said Milstead.

And that’s exactly to what this gentleman did three years ago in South Carolina.

“There is the famous 22 pounds of Tannerite,” the man in the video using a large amount of explosives said.

Upset with the company that makes Yeti coolers, he decided to blow his up.

KELOLAND News talked with a representative with the ATF Office in Minneapolis. She tells us the binary explosives are often sold in kits. Two chemicals which by themselves are safe and legal and unregulated. But when mixed together they form a powerful explosive.

The Tannerite website says it takes a bullet traveling at least 2-thousand feet per second to cause the chemicals to explode.

Milstead says there are legitimate uses for Tannerite,

“People enjoy using Tannerite some of the shooting enthusiasts you know have an exploding target but like anything, if you mix too much of it it can be dangerous and so you just ask people to use common sense, and sometimes that doesn’t always happen,” said Milstead.

The sheriff says the landowner trying to blow up the tree west of Sioux Falls has no plans to repeat the process. The ATF reminds everyone that once the binary chemicals are mixed the explosive should not be transported without a federal license.