Last night's episode of the Walking Dead got me hankering for some smoke grenades. They've been one of those "nice to have" items, way down the list of priorities--and the expense has kept 'em there. Why would you want 'em? The main uses are two fold - signalling and concealment. Concealment is what I'd be most interested in using 'em for, but they're excellent for signalling aerial rescuers, too.
Unfortunately, it looks like I missed the boat on ml-spec, real deal smoke grenades. ALS, the manufacturer of said smoke grenades, no longer sells to civilians. Apparently the fuse contains a very small amount of controlled explosives, and ALS got pressure from the ATF to cease sales.
Currently, as far as I can tell, it is not illegal to possess these grenades or even resell them if you own some privately (state laws will vary, of course). But ALS isn't selling them new, so we're left with whatever is out there on the second-hand market, which looks to be pretty scarce. And of course, I'm not a lawyer, so check your laws before putting down any money.
You can probably still find 'em at gun shows, but who knows what the prices will look like. Military smoke grenades are M-18s, and the ALS grenades are similar in - cylindrical, metal with a pull ring and spoon - like you'd expect from a smoke grenade.
All is not lost, though - there are still options out there.
First up are grenades from sportsmoke.com - they're designed for airsoft/paintball and have a pull-ring fuse. Videos show a good amount of smoke, and they apparently burn "cool" - less likely to start a fire or burn someone than the military style. There's no safety spoon and the body is a cardboard tube, so I'd be concerned about long term reliability. Paintball suppliers sell 'em, and you can order from their website if you pay a HAZMAT shipping charge. You're looking at under $10 a grenade, though, so not too steep. They also have electronic ignition grenades if you want to do some command detonating.
Another, more robust option is marine smoke signals. Check out your boating stores - the Coast Guard requires 'em as a daytime signal in some cases. These have the added advantage of working in and around water, floating, and being designed for long term storage. They have self contained ignition, too, so no need to have a lighter.
Orion is one of the main U.S. manufacturers, and they make "smoke signals" in a variety of sizes - these little guys and bigger ones, too. Here's a demo of a larger one - a bit bigger than grenade size. Your in-person prices will be a lot better than ordering online, as I'm sure these all carry HAZMAT charges. Some places will sell "expired" smoke signals - they've passed their shelf life and they no longer meet regulations for signaling, but not a bad option if you want some on the cheap for practice/testing.
And, apparently, smoke grenades are not particularly complex to make on your own, so that's an option. Do so at your own risk, and I'd be very hesitant to trust a basement scientific experiment for anything critical, though.
So - unfortunate, but real military/law enforcement smoke grenades are not readily available these days. There are still options available to us civilians that do pretty much the same thing--they're not ideal, but they can be pressed into service if needed. I think either airsoft or marine smoke signals can work, depending on your needs.
Rumor around the internet is that ALS may potentially release smoke grenades with a different ignition mechanism, but we'll see if that ever happens. What's ridiculous is that you can buy a 37mm grenade launcher and ALS 37mm smoke grenades without difficult. The hand held/thrown variety, though - nope. Gotta love it. And I'm sure we're only going to get worse in the coming years.