Updated

The cell phone industry hopes to have a directory for wireless phone numbers by the end of this year, but privacy advocates, lawmakers and some industry officials worry that consumers could be in danger of losing the anonymity cell phones provide.

163 million Americans use wireless telephones in addition to their home landlines, and 7.5 million to 8 million consumers use wireless phones only, according to the Cellular Telecommunications and Internet Association (search).

For the increasing number of consumers "cutting the cord" and going wireless-only, a directory is indispensable, CTIA officials say.

"They have no directory of their own. This is an opportunity to provide them with one if they choose to be listed," said CTIA Spokesman Travis Larson.

Larson said the industry would put in place safeguards to protect the privacy of consumers, including an opt-in system so that those who do not want to be listed will not be listed. He said the service would only be available through 411; there would be no print directory. Additionally, the list of numbers would not be sold to third parties to limit the ability of telemarketers to use the directory.

Industry representatives insist they will carefully guard consumer privacy, but privacy advocates say a self-policing industry is not enough, and even with the best internal standards, outside safeguards are vital.

"We feel that self-regulation really isn’t the way to go. Let's say you have a wireless provider that transgresses an industry standard. We question what would happen," said Jordana Beebe, spokeswoman for the San Diego-based Privacy Rights Clearinghouse (search).

One bill now sitting in Congress aims to address those concerns. The Wireless 411 Privacy Act (search), introduced last November by Rep. Joe Pitts, R-Penn., and Ed Markey, D-Mass., would provide an “opt in” for existing users, meaning that wireless carriers would have to obtain clear preauthorization from all existing customers before including the user’s name and phone number in the directory. For new users, there would be an "opt out" option in which a clear mechanism would be made available for wireless users declining to participate in the directory.

The bill would also mandate that no fee be charged for those who desire not to be listed.

"Home phone numbers have been listed and sold to telemarketers for years. We don’t want that to happen to wireless numbers. This bill strikes a good balance between allowing industry to grow while protecting consumers," Pitts said when the bill was introduced.

"He views his cell phone, as a consumer, as private. He gives it out to friends and family and some colleagues. When his cell phone rings, he expects it to be important," Pitts' spokesman Derek Karchner told Foxnews.com, adding that Pitts believes a directory could be a great service, but it has to be done the right way.

Beebe said her organization supports the legislation, though she worries that the opt-out option would have to be strengthened so new users are clearly informed about their choices of either being included or left off the list.

Larson said these safeguards provided by the industry meet all the provisions introduced in the legislation.

"We have a long history of protecting consumer privacy. ... The wireless industry doesn’t feel legislation is necessary at this time. We think the industry can and will police itself effectively," he said.

Though the Wireless 411 bill has been sitting untouched in the House Subcommittee on Telecommunications and the Internet since last December, the effort to get the directory up and running by year's end faces a separate obstacle — the nation's largest wireless carrier, Verizon, has chosen not to be a part of it.

"We don’t think the time is right for it. Most people come to us looking to have their phone number private, and we respect that," said Verizon Wireless spokeswoman Brenda Raney.

Raney said wireless users don't need a separate directory because they can already ask local carriers to list their phone numbers. So for those who use only a wireless phone there is a way for them to be listed, should they choose to be.

Larson said CTIA does not regard Verizon's abstention as a fatal flaw because it is already an optional directory that would be a subset of all consumers.