More than two months since dozens of fiery explosions tore through the Merrimack Valley, killing one person, injuring several others and cutting off gas service to more than 8,600 homes and businesses, a U.S. Senate panel held a hearing Monday, seeking answers to the questions: How did this happen? How can it be prevented in the future? And who should be held responsible? Jim Braude was joined by WGBH News Reporter Adam Reilly.
