ROYAL OAK (WWJ) – As the rhetoric ramps up over North Korea and nuclear weapons, the cash registers have been ringing at a local Army Supply store, where some are apparently prepping for a third World War.

Ben Orr, the manager of Joe’s Army Navy in Royal Oak, says he’s been selling a lot of “prepper items” over the past week or so.

“We’ve been very busy. Unusually busy, I’d say,” Orr told WWJ’s Sandra McNeill. “It’s definitely an increase, just in selling all the normal prepper stuff, end of the world stuff. A lot of water prep stuff, food, MREs — the military meals.”

And there’s been a substantial increase in the sale of a particular item they don’t sell much of — a so-called radiation antidote called potassium iodide.

“It actually stops your thyroid from absorbing any radiation. So, it fills your thyroid with iodine, which it normally does anyways,” said Orr. “Your body can’t tell the difference between bad, radioactive iodine and acceptable iodine, so it actually will stop you from getting thyroid cancer.”

The antidote is usually hard to find, but Orr’s store carries two brands.

“It’s supposed to work. It’s FDA approved. But they also recommend you don’t take it unless the government says to take it,” he said. “Unless people are scared of something, we don’t really ever sell it.”

Another popular request: gas masks. But most people looking for those will be out of luck.

“Gas masks are a big thing too, but we only sell them as novelty,” said Orr. “A lot of them are out of date and we don’t guarantee them to work.”

Orr said most people come in and make their purchases without giving any explanation, but a few people have mentioned North Korea.

“Some woman came in earlier and said she had to get it because of little Kim (Jong-un),” he said. “I don’t know if she was making a joke or just got it mixed up.”

Earlier this week, North Korea announced a detailed plan to launch a volley of ballistic missiles toward the U.S. Pacific territory of Guam, a major military hub and home to U.S. bombers. The announcement warned the North is preparing a plan to fire four of its Hwasong-12 missiles over Japan and into waters around the tiny island, which hosts 7,000 U.S. military personnel on two main bases and has a population of 160,000. It said the plan could be finalized within a week or so and would then go to leader Kim Jong Un for approval. It would be up to Kim whether the move is actually carried out. It said the missiles would hit waters 19 to 25 miles away from the island.

It’s unclear whether North Korea would risk firing missiles so close to U.S. territory, which could provoke countermeasures and further escalation. North Korea frequently uses extremely bellicose rhetoric with warnings of military action to keep its adversaries on their heels. It generally couches its threats with language stating it will not attack the United States unless it has been attacked first or has determined an attack is imminent. But the statement raised worries amid a barrage of threats from both sides.

President Donald Trump tweeted Friday that the U.S. military is “locked and loaded” if North Korea acts “unwisely,” escalating an exchange of threats between the nuclear-armed nations. As it is, the U.S. has a robust military presence in the region, including six B-1 bombers in Guam and Air Force fighter jet units in South Korea, plus other assets across the Pacific Ocean and in the skies above. U.S. military options range from nothing to a full-on conventional assault by air, sea and ground forces. Any order by the president could be executed quickly.

Military solutions are now fully in place,locked and loaded,should North Korea act unwisely. Hopefully Kim Jong Un will find another path! — Donald J. Trump (@realDonaldTrump) August 11, 2017

Orr says it’s not a bad idea to be prepared for an emergency, but he’s not sure we need to get ready for the end of the world just yet.

“I have a little bit of stuff at home. I don’t really prepare much for the radioactive scenario because it’s probably not much to prepare for on that front,” he said. “But I don’t think it’s a bad idea to have some food and water tucked away by any means.”

© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.