A gas trade group has filed a formal ethics complaint against an anti-fracking group that includes such celebrities as Lady Gaga, Alec Baldwin and Yoko Ono. The celebrity coalition was under scrutiny last month for failing to register as a lobbying organization in New York, and now the Oil & Gas Association wants the organization investigated for breaking state lobbying laws.

Organizations must register as lobbyists in New York if they spend $5,000 or more to influence state legislation.

Artists Against Fracking has spent an undisclosed amount to influence fracking legislation, including billboards, full-page ads in the New York Times, TV ads and a website where people can donate money for their campaign, according to the complaint filed by Brad Gill, executive director of the Oil & Gas Association. (See the complaint in the embedded viewer below this story.)

“The public has been unable to learn how much money is being spent on this effort, what it is being spent on, and who is funding the effort,” wrote Gill. “I understand the power of celebrity that this organization has brought to the public discussion over natural gas development, but I do not understand why this organization is not being required to follow the state’s lobbying law.”

Artists Against Fracking claims its activity is protected as free speech, according to the Associated Press.

“As private citizens, Yoko and Sean (Lennon, Ono's son with the late Beatle John Lennon) are not required to register as lobbyists when they use their own money to express an opinion and there’s also no lobbying requirement when you are engaged in a public comment period by a state agency,” spokesman David Fenton told AP.