Evidently he ask the wrong question.
Check it out:

A reporter has been detained by Capitol Hill police for trying to ask a question of Environmental Protection Agency administrator Gina McCarthy.

Bloomberg BNA energy reporter Ari Natter tweeted about being detained.

#transparency RT @AriNatter: I am being detained by Capital Police for trying to ask @EPAGina a question after her remarks.

— nickjuliano (@nickjuliano) March 28, 2014

Natter was detained while covering the American Council On Renewable Energy conference, where McCarthy spoke.