EQT Corp. spokeswoman Natalie Cox said the company shut down the rig in Moshannon State Forest in central Pennsylvania at midday. The rig was just being commissioned, and protesters said it had gone up in the last week.
Cox said the Pittsburgh-based company's primary concern was the well-being of its employees and contractors.
"The safety of everyone involved is our primary concern, including employees, contractors, police officers and the protesters themselves," Cox said. "Therefore, operations will not resume until we are assured it is safe to do so."
Gloria Forouzan of Marcellus Protest said 150 demonstrators had blocked an access road for trucks headed to the EQT rig.
State police are at the site monitoring the situation. No arrests have been made.
Another protester, 25-year-old Alex Lotorto of Pike County, said two activists were sitting 75 feet in the air on a tree platform that had been connected to a cable stretched across the access road. If a truck or machine were to cross the cable and cut through it, the tree sitters would fall, Lotorto said.
"Unfortunately, this is the extent we have to go to," said Lotorto, who has lived in rural Pennsylvania since birth.
Hydraulic fracturing, or fracking, is a drilling method that involves pumping chemical-laced water at a high pressure into the ground to release gas and oil. Environmental groups fear the process could poison water supplies. The industry says it's safe.
Lotorto said the new rig and fracking process was spoiling the forest, a treasure for the local economy. But most of all, he said, he was upset about "the disrespect that this industry has shown to residents throughout the state."
He said the protesters wouldn't leave until EQT took the rig away.
"We'll happily move all the barricades when the equipment moves out," he said.