Tim Sander, a resident of the Central Hillside neighborhood in Duluth, hasn't been able to sleep through the night lately without waking to the sound of fireworks going off at various hours.

While the sound of fireworks during the warmer months isn't anything new to Sander, he said it seems to have grown louder and more frequent. If it was closer to the Fourth of July he'd understand, but now he's had enough.

"Why should I have to be used to hearing it?" Sander said. "What they're doing is illegal. Period. It's illegal. And most of all, it's annoying."

He's one of many in the neighborhood voicing their frustrations. Dozens have shared similar concerns on Nextdoor, a social networking app for neighborhoods. The city of Duluth is also fielding calls and messages from irritated residents.

In Minnesota, any firework that flies or explodes is illegal without a special permit. The full list of what is and isn't legal can be found on the Minnesota Department of Public Safety's website.

Duluth Fire Marshal Corwin Groom said that even the legal fireworks can be unsafe during a dry period like the one Duluth is currently experiencing. As of Thursday evening, Duluth had received only a quarter-inch of rain in June — 2 inches less than normal.

"Whenever we have a drought that coincides with the Fourth of July, that makes us more concerned than usual," Groom said. "Even though something might be legal, even though something might be safe most years, it can become unsafe in a drought year like this."

The Duluth Fire Department is asking residents to use common sense and safe practices when opting to use legal fireworks. That includes ensuring kids aren't using them without supervision and that a method for extinguishing is always available in the case of an inadvertent brush fire.

"I think we've all been cooped up for several months. We're all ready to have a celebration," Groom said. "So this is a good time as well to get to know your neighbors before the Fourth of July and make sure that what you're doing doesn't infringe on them too much."

Ingrid Hornibrook, public information officer for the Duluth Police Department, encouraged the public to call 911 as soon as they hear illegal fireworks to increase the chance of finding out who's lighting them. She said it's common for dispatch to take calls from residents reporting fireworks.

"Unless we can arrive there at the time it's happening, it's one of those things that's impossible to find out who's doing it because as soon as squads show up, they're not going to light off fireworks," Hornibrook said. "It's hard to hear where they come from because the sound reverberates."