Advocates of "clean coal," hopeful of pushing their cause at Obama-Biden campaign events, say that organizers have confiscated T-shirts, hats and signs and harassed supporters.

At a Chesterfield, Virginia rally Tuesday for Vice President Biden, clean coal supporters said that their T-shirts, hats and signs were taken as they passed through security. Others said that they were barred from entering after an official who had earlier confiscated clean coal T-shirts called it a "private event."

Wednesday at a rally for President Obama in Bowling Green, Ohio, clean coal advocates in their T-shirts and hats were asked to leave and their video tracker filming their treatment was filmed by an event video tracker.

Officials at the American Coalition for Clean Coal Electricity say they are flummoxed by the actions. They have been pressing both Obama and the Romney campaigns to endorse their goal of promoting high tech coal plants that produce cleaner energy and do not yell or jeer at political rallies. The advocates stand out in their blue shirts and hats, some of whom even made to the floor at last month's Republican National Convention in Tampa, Florida.

It is unclear exactly who at the rallies are policing the crowd. Last week, a University of Florida student wearing a McCain T-shirt war barred from entering an event on campus for first lady Michelle Obama. At the time, an organizing aide said the rally was only for supporters.

The Obama campaign's energy plan ignored clean coal until it was pointed out by the media. After that the technology was added to the website dedicated to energy. Ironically, Biden signed a Clean Coal hat last year.

But the president favors renewable energy and coal country is worried that he will limit the use of coal if reelected.

Lisa Camooso Miller, vice president for media relations at the clean coal coalition, said that the restrictions on advocates "has been going on for months."

She said that "ours is an issue awareness campaign. We bracket both Romney and Obama with street teams. We do it everywhere but 2012 was the first time we've been told we can't do it."

In photos the group provided to Secrets, an event worker in a mint colored shirt is shown collecting clean coal T-shirts and then in the video she calls the public rally a "private event."