Explosion frightens residents, knocks out windows after lawnmower runs over propane tank.

The sound of a lawn mower usually evokes happiness.

If grass is getting cut, that means the weather is warming and summer is on its way. 

Those pleasing thoughts may turn to shocks of horror when growl of a mower engine is replaced with an explosion.

"I heard the mowers on so I thought 'oh, okay, they're about to do something to this lot," said Danielle Thomas. Then, out of nowhere she heard another sound. "Big explosion, kaboom. I'm like 'what?'"

Thomas glanced out the window and bore witness to a fireball engulfing the air. 

The tangible evidence of what made things go 'boom' was pretty obvious. A grey propane tank charred by fire with a sizeable hole in the side was the culprit.

"I guess one of the blades hit the propane tank and it blew up," Thomas said. "Clearly they did not assess what they were going to cut before they cut it."

'They' in this scenario are city workers contracted to cut city land. Around 8 a.m. on Wednesday, they were cutting a plot of land with overgrown grass known for dumping. Thomas, as well as her landlord have both complained to the city about the state of the land parcel. 

The explosion was big enough it also knocked out several windows in the house.

"Every window on the side of the house is busted and one in the back," Thomas said. "Glass everywhere."

The city released a statement saying they request all contractors to look at the property before addressing the lot. 

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The issue of pervasive illegal dumping in the city has been a problem in Detroit for years. While no one was hurt, Thomas hopes the incident will serve as an incentive to stop dumping in the future.