Public Service Commissioner Ronald A. Guns, who opted out of a major telecommunications hearing three weeks ago because an adult son works for Verizon Communications Corp., has participated in another Verizon case this week - to the dismay of competitor AT&T; Corp.

AT&T; filed a formal request with the commission Wednesday asking that Guns recuse himself from a new round of hearings that conclude today, spokesman Jeffrey Roberts said.

"The grounds have not changed at all. It's the same set of circumstances and the same conflict," Roberts said.

The commission will likely respond by next week on whether Guns should participate in the months of deliberations that follow this week's hearings, said Susan Stevens Miller, general counsel for the commission. The commission is deciding on the prices that Verizon can charge its customers.

Guns could not be reached for comment yesterday.

His appointment to the $93,000-a-year post by Gov. Parris N. Glendening last year was controversial from the beginning for some in the state's telecommunications industry because Guns worked 29 years in marketing and communications for Verizon, the main provider of local telephone service in Maryland.

Competitors, including AT&T;, said they were uncomfortable with a former Verizon employee deciding on the balance of power between phone companies.

Although the commission and a Baltimore Circuit Court judge denied AT&T;'s request to remove Guns from a phone case last month, Guns eventually decided to withdraw - not because of his history with Verizon, he explained, but because a son has worked for the company for four years.

"It concerns me that some parties may not have known that my son works for Verizon," Guns said in removing himself Nov. 1. "Because I've always tried to be open and above board about my prior relationship with Verizon ... it compels me to recuse myself from this proceeding."

Because he removed himself from that case, which involved Verizon's request to begin offering long-distance phone service in Maryland, AT&T; officials were surprised when Guns appeared at a different set of phone hearings this week.

"The circumstances are different in this case," said Miller, the commission attorney. "Commissioner Guns recused himself because we discovered that many of the parties didn't know his son worked there. Now, all the parties are aware."

It is not rare in the world of utility regulation for staffers or commissioners to have worked in the industry they regulate, or to move from the public agencies to jobs in the private sector.

For example, Kathleen Abernathy, a member of the Federal Communications Commission, formerly was an executive of Qwest Communications International Inc., the regional Bell company in the western United States.

"There's nothing from a legal perspective that would require a commissioner to recuse himself because of his son," said James Bradford Ramsay, general counsel for the National Association of Regulatory Utility Commissioners in Washington.

If a commissioner took action that would affect the salary of a family member, or had begun working on a case while in the private sector, those would constitute more direct conflicts, he said.

AT&T; is arguing that Guns should recuse himself because his vote could ultimately affect Verizon's market and level of employment, perhaps affecting Guns' son.