It was a signature achievement for Montgomery County Council member Hans Riemer: passage of the 2012 Open Government bill, which requires all county departments to make public records more available and accessible through a central Web portal.

“You have a right to know what your government is doing. And I have made protecting that right a central part of my work,” Riemer (D-At Large) said in his campaign literature as he ran for reelection in Maryland’s largest jurisdiction in 2014.

Last week, however, after more than 200,000 email addresses of people receiving newsletters and other information from the county government were made public on the county’s website, Riemer and some of his colleagues decided they had opened the portals of government a bit too wide.

What followed was an example of how the competing interests of government transparency and personal privacy can create serious friction.

A five-member majority of council members — Reimer, Nancy Floreen (D-At Large), Sidney Katz (D-Rockville-Gaithersburg), Nancy Navarro (D-Midcounty) and Craig Rice (D-Upcounty) — ordered their attorney to pull back from public view more than 90,000 of the email addresses published on DataMontgomery , the portal created under Riemer’s bill. The bill required publication on the portal of any information released through a Maryland Public Information Act request.

The lawmakers who authorized the deletion said they feared that tens of thousands of residents subscribing to newsletters would be the targets of spammers if they did not act.

“This is like a treasure trove for marketers,” agreed Council President Roger Berliner (D-Potomac-Bethesda), who was not one of the five. Publication of the addresses, he said, could have created a “chilling effect” that would prevent many of the county’s 1 million residents from interacting with local government.

Pulling the email addresses violated the 2012 law, which is similar to new open-government statutes in other states and localities. Riemer said the decision was forced by “exigent circumstances” and argued that the public interest served by mass distribution of the addresses was outweighed by privacy concerns.

“A lot of people would be very upset by signing up for the county’s solid-waste newsletter and having their [email addresses] end up in 24 political campaigns and 150 different spammers,” he said.

He has drafted an amendment to the Open Government law that would bar such email disclosures in the future. It will be introduced at the council’s April 4 session.

John Verdi, vice president for policy at the Future of Privacy Forum, a nonprofit group that promotes best data practices, said the email-address issue illustrates what is becoming a familiar conflict.

“Everybody agrees that transparent government is a good thing,” said Verdi, a former Obama administration official who worked on privacy issues. “You have data that is purely government data, and data appropriately excluded by public information laws. Then you get the gray area in the middle, where an increasingly important question being asked is about the right balance between openness and privacy.”

Verdi said Montgomery’s experience “highlights government’s responsibility to provide notice to folks that information they submit might be made public.”

The release of the torrent of addresses started with a Public Information Act request by MocoVoters, a new grass-roots group that wants to increase turnout at the polls in the 2018 elections. Its co-founder, Robert Lipman, was active in opposing the county’s plan to redevelop the Westbard neighborhood of Bethesda.

As first reported by Bethesda Beat, the group asked for email addresses of subscribers to all County Council newsletters and to Paperless Airplane, an electronic newsletter put out by Montgomery’s public information office.

That meant a total of more than 200,000 addresses forwarded to MocoVoters, and posted on DataMontgomery.

Leaders of MocoVoters wanted to use the addresses to inform voters about issues such as the influence of real estate developers on incumbent council members and the potential for electing new faces through the public campaign finance law.

“Our democracy works better if outsiders have an ability to communicate with voters about the upcoming elections,” said Lipman.

Some council members were not so enthusiastic about handing over email addresses to an advocacy group they regard as less than friendly. But their attorney, Amanda Mihill, said they had no choice.

Public information director Patrick Lacefield got the same advice from counsel regarding subscriber lists for Paperless Airplane.

As it turns out, once MocoVoters received the email addresses, it had second thoughts about using them.

For one thing, the group needed help with the sheer volume of data it had accumulated. It consulted with MailChimp, the email marketing platform, which said that as a matter of policy it didn’t handle email addresses acquired from third parties, which in this case would be the county.

Instead, Lipman said, the group will grow its own address list, using social media to draw potential members.

In recent days, the public-information request has spawned at least two bogus copycats. On Friday, someone claiming to be Lipman filed a request for all phone numbers in the emergency alert system operated by the county. The request was immediately declined on security grounds.

The second was a parody of an old Internet scam. A person claiming to be Mohammad Abacha, a son of the late Nigerian president, Sani Abacha, asked that all emails the county had received from Lipman, the MocoVoters group and the Parents Coalition of Montgomery County be posted on DataMontgomery.

In an email to the county council, the writer who called himself “Montgomery County Nigerian Prince,” also thanked the county for the email addresses it had already made available on the portal.

“It is my pleasure to contact each and every one of these individuals for a business venture I intend to establish in Montgomery County,” he wrote, adding that he has access to $13.2 million that he wants to invest in the county “for security and political reasons.”