A bill that would replace the Federal Communications Commission’s expiring net neutrality rules within California — and potentially affect Internet service throughout the country — gets its first key test Tuesday, culminating weeks of intense lobbying from both sides.

SB822, authored by state Sen. Scott Wiener, D-San Francisco, gets its first public hearing before the Energy, Utilities and Communications Committee with a long list of supporters, including three former FCC commissioners, coalitions of small businesses and startups, and the mayors of several cities.

“We rightly fear that without regulations, (Internet service providers) will abuse their power anti-competitively in ways that harm consumers,” said a letter signed by the mayors of San Francisco, Los Angeles, San Jose, Oakland, Sacramento and Emeryville. “Net neutrality is about ensuring an equal playing field for all voices, companies and products on the Internet.”

However, an equally long and diverse list of opponents that say the bill goes too far includes AT&T, the California Cable & Telecommunications Association, a Boys & Girls Club chapter and the state conference of the NAACP.

US Telecom, a trade association representing broadband Internet companies, said California should not hand over Internet authority to the state Public Utilities Commission.

“Although we support net neutrality, our concern was that this heavy handed public utility framework would inevitably chill investment and innovation,” the letter said.

Wiener’s bill is one of two net neutrality bills introduced after the FCC voted in December to rescind rules, adopted during the Obama administration, that required Internet service companies to treat all Web traffic equally.

Those rules, set to officially expire April 23, were meant to prevent major companies like AT&T, Verizon, Comcast and Charter Communications from unfairly blocking, throttling or charging companies and organizations for access. Those companies have repeatedly denied they intended to break the principals of net neutrality, while FCC Chairman Ajit Pai said the order was needed to return to a “light-touch” regulatory scheme that previously allowed the Internet to thrive.

One bill, from state Sen. Kevin de León, D- Los Angeles, passed the Senate and is pending in the Assembly. But Wiener’s bill is drawing attention nationally because it is far more comprehensive and would put into law the regulations the FCC threw out. It includes protections for public safety and emergency notification messages sent through the Internet.

A support letter from the American Sustainable Business Council said the FCC rules closed loopholes that Internet companies had already exploited. “The open Internet has made it possible for us to rely on a free market where each of us has the chance to bring our best business ideas to the world,” the letter said.

Tom Wheeler, who as FCC chairman wrote the Obama-era net neutrality rules, told The Chronicle that Wiener’s bill was the “most sweeping” bill of its kind in the country.

“What is important right now is that California is going to lead the way,” Wheeler said. “If California starts down the path, then the other 49 states can say, ‘Look how it’s done in California and this is the right way to do it.’ Someone has got to set the standard. It’s incredibly important that California leads the way.”

In a statement, AT&T said the bill “introduces an entirely new regulatory scheme” for the state to administer. “That will harm the state’s Internet economy by reducing competition and investment, leading to less innovative products and services,” AT&T said.

An analysis by the Energy, Utilities and Communications Committee recommended removal of several of the bill’s provisions, including one that could prevent Internet providers from using a practice called zero rating, which provides free access to select websites in exchange for conditions like subsidized advertising.

“To the extent that sponsored data plans provide consumers with more access to data at a lower cost, prohibiting beneficial forms of zero rating could increase consumers’ data costs in the long-term,” the analysis said.

“Ending free Internet data is particularly harmful to younger, low-income and minority Californians who are more dependent on their mobile devices to access the Internet,” the California State Conference of the NAACP said.

Kathleen Abernathy, an FCC commissioner from 2001 to 2005 and now an attorney with Wilkinson Barker Knauer, also argued that one state should not be allowed to impose controls for a service that crosses state and international boundaries.

“We can’t have 50 sets of rules here,” Abernathy said in an interview. “Do we really want a single state to dictate how products and services are going to be rolled out across the country? You’d create a patchwork of regulations that make investment and deployment incredibly challenging and risky.”

Benny Evangelista is a San Francisco Chronicle staff writer. Email: bevangelista@sfchronicle.com Twitter: @ChronicleBenny