An Iowa city has passed an ordinance requiring hundreds of commercial buildings and apartment complexes to literally leave the keys outside in case of an emergency, allowing quicker access to first responders but potentially to those up to no good, as well.

The Cedar Falls City Council voted 6-1 on Monday to expand an existing 2004 ordinance that required lock boxes containing keys at buildings with six or more units and commercial buildings with sprinkler system or unsupervised alarms. The new ordinance, which can become law with a signature by Mayor Jon Crews, expands the requirement to apartment buildings with just three or more units.

Nick Taiber, the lone council member to oppose the ordinance, told FoxNews.com the issue has led to allegations of overreaching bureaucracy and constitutional concerns. He said he has yet to see a "strong case" for the benefits of requiring the safe-like boxes located on the outside of buildings so fire officials, with a master key, can gain entry during emergencies. With at least 841 commercial properties in Cedar Falls, Taiber estimates the cost of expanding the ordinance will cost the city roughly $500,000.

"That's probably a low side," he said. "I keep asking what the net impact here is, and nobody can give me an answer. And that's a lot of keys to manage."

Proponents of the measure say expansion of the ordinance to include additional apartment buildings will lead to increased ease of entry during emergencies and a reduction in property damage. But Taiber and other critics have said that the mere presence of lock boxes increases the potential for a property to be breached, as well as raising potential issues regarding the 14th Amendment, which guarantees equal protection of life, liberty and property.

"It probably presents some equal protection issues," Taiber said, arguing that having a lock box would present a higher risk of a property being entered by unauthorized persons. "The issue with me is that if you have a lock box, you're more likely to be breached."

Taiber said he wasn't surprised by the outpouring of criticism by local residents during Monday's vote.

"You're talking about private property here and commercial businesses," he said. "This is a pretty sensitive matter, and unless you can prove without any doubt that this ordinance is going to provide more benefits than it'll cost, both tangible and intangible … it's government expansion on a local level."

Taiber continued: "You have to ask the question: What's next?"

Mayor Crews and Cedar Falls Fire Chief John Schilling did not respond to requests for comment on Wednesday.

During earlier meetings held on the ordinance in March, another resident cited quotes from Benjamin Franklin and Thomas Jefferson while questioning whether ease of access is worth the loss of freedom for property owners, according to the Waterloo-Cedar Falls Courier.

Council member Frank Darrah, who voted in support of the ordinance, sought to table the issue prior to Monday's vote for additional review. He reiterated that call on Wednesday, saying the safety of Cedar Falls residents remains the top priority.

"However, I think we're a month behind on this," he said. "We should've had this discussion a month ago instead of after the fact, to allow us to rethink this."

Despite that concern, Darrah said he voted for the measure because he did not want to appear as kowtowing to threats received by his office and that of other local politicians by Cedar Falls residents and elsewhere. The threats, "if not direct," were implied, Darrah said.

"The emails were so offensive," he said.

During discussions with Crews, Darrah said the mayor told him that he is considering a task force to analyze the issue further before signing it into law, as well as taking a look at other cities nearby -- like Waterloo -- that have similar legislation.

"I'm not comfortable with it being mandated," Darrah said. "I don't want people to perceive that that's what we are: not responsive to the concerns of our citizens."