With the 4th of July almost upon us, an alarming trend has popped up again, one that can pose a threat to dogs, tennis ball bombs.

The idea is nothing new, but in recent years has become more of a problem around the 4th of July, and across the country.

Simply put, people take a tennis ball, cut it down the middle partway, and stuff it with gunpowder from fireworks or other explosive devices. A fuse is attached, and it will usually blow up.

Police in Kent, WA issued a warning to residents, as have several other Seattle-area communities, after yet another tennis ball bomb was found this last week. One was found earlier in February in a city park by an explorer.

They're often hidden, and can pose a threat to dogs especially.  Even if the fuse is not lit, or it does not explode, the animal could ingest some of the contents and get very sick.

It's not just in Seattle, it's a nationwide issue as well. A number of animal information websites have had articles recently about this issue.

A search of the web indicates there's even websites that show how to make such bombs, but we don't dignify them by including links.

Authorities, of course, say if you find one, call them immediately.  Look for tennis balls that are cut, wrapped fully or partially in duct tape, or have any strange strings or other noticeable objects sticking out of them. They're usually the fuze.

Other similar uses, like the one pictured here, are creating tennis ball sparklers, using existing fireworks.