Peter Butler knew the St. Paul recycling cart he received two years ago had a radio chip in it that could help track his disposal activity. So, when he spied something shiny on his new city garbage cart last fall, he had a pretty good idea what it was.

He took a needle-nose pliers and yanked it out.

A radio frequency identification (RFID) chip is built into each of the 80,000 new garbage carts the city acquired last year. But, a city spokeswoman said, neither St. Paul nor its garbage haulers are using them to track anything.

Butler, a Highland Park resident and outspoken garbage plan nemesis, doesn’t trust the city, so he made a video of himself removing the chip and posted it on Facebook.

“We don’t know how they’re going to use it,” Butler said. “There’s always the potential that they could use it for other data collection purposes.”

Thousands of St. Paulites who have already tried to stop the city’s organized garbage collection because of rate changes and inflexible rules have added a new complaint: It’s an invasion of privacy. Cities across the country are using RFID chips to help track and manage their cart inventory. Some are also using them to record who is putting their recycling bins out at the curb or who might be putting recyclables in with the trash, said Benjamin Feist, legislative director for the American Civil Liberties Union of Minnesota.

As cities push to use technology in more areas of our lives, government data collection raises privacy red flags, he said. “I think we definitely have the potential for government surveillance just because the chips are in the cans.”

Matt Sletten, who lives in the North End, was already so upset about the garbage plan that he returned his new cart to the city. He’s tried to cancel his service (the city won’t let him) and he’s refused to pay his bill. So he said he was surprised to get a call from city officials asking him when they should deliver his replacement cart.

“How’d they know?” he said. “I think they used the chip to know I needed another can. How else are they tracking a service that I have not been receiving?”

Probably by reading the serial number that is posted on the outside of the cart, said Lisa Hiebert, a Public Works spokeswoman. In addition to the chip, each cart has a visible serial number. It’s old-fashioned, but it’s the only way the city is keeping inventory of the carts.

“We are not using the chips. We don’t have the equipment to use the chips,” she said. “Neither do the haulers.”

Hiebert said the city is not snooping in your garbage. “I know — Big Brother and everything — but we’re not.”

However, she said it’s not a good idea to pry the chip out. The carts are city property and if they’re damaged, property owners can be liable for paying to replace them.

On Oct. 1 last year, St. Paul rolled out a new organized trash collection system that issued city-owned carts to more than 70,000 property owners. It was the first time in city history that residents were required to hire someone to cart away their trash. Officials estimate that before the new plan started, 9,300 St. Paul households did not contract with a hauler.

The city’s contract with a consortium of eight haulers standardizes rates, pickup days and area assignments. The contract limits neighborhoods to a single garbage pickup day per week with a single hauler, a move that has dramatically reduced garbage truck traffic on city streets and alleys. After the first three months, the plan won praise from residents who have seen costs — and early morning neighborhood noise — go down.

But the plan immediately sparked consternation and complaints — and an uprising.

Opponents who had collected thousands of signatures on a petition demanding St. Paul put the garbage plan to a vote say they are preparing to file a lawsuit after the City Council voted in November to not put it to a citywide vote. There are myriad reasons opponents say they dislike the plan, from having to pay more to being prohibited from sharing a cart. Every household up to a fourplex must have its own cart, which landlords of smaller rental properties say has dramatically driven up their costs. Still others, like Sletten, say they produce so little waste that they don’t need a cart — and they shouldn’t have to pay for one.

Butler, who is suing the city over the system’s pricing and is also involved in the petition drive, doesn’t necessarily think St. Paul officials are nefariously collecting private data from residents’ trash — yet.

But the city’s contract with the haulers consortium requires haulers to submit reports on how much trash they are collecting, how many home electronics items are showing up in carts and how many bulky items they are picking up, he said. It’s not a stretch to think the chips could be used for that.

“My main point is they should inform people about the chip, tell them what information will be collected and whether they consent or not,” he said.

Feist of the ACLU said privacy concerns should not be pooh-poohed. It all depends on where cities go from here.

“It really could be very invasive,” he said. “Even if it is just a garbage can.”