Capt. Kristjan B. Laxfoss via AP
A Shell drilling ship drifts near shore on Unalaska Island, Alaska, on July 14. ship lost its mooring but did not ground and was not damaged, the Coast Guard said.
The first drilling in Arctic waters off Alaska later this summer is being curtailed, Shell said Tuesday. The company focused on the ongoing presence of sea ice, while environmentalists pointed to the fact that Shell has yet to get certification for its spill containment system.
Shell had planned to drill five exploration wells this summer but now will aim for two as well as additional "top hole" locations, "meaning we will begin new wells which can be completed in 2013," Shell spokeswoman Kelly op de Weegh told NBC News.
"We have continued to be delayed by the sea ice in place, and while the ice is just now beginning to clear near one of our locations, we are still monitoring for ice to clear elsewhere," she added.
"If the ice had been cleared, we would be awaiting final testing and certification of the containment barge,' she said.
The containment system was being tested Tuesday and later in the week, she said, adding that "we feel very good about the progress we’ve made."
The drilling will be in the Beaufort and Chukchi Seas. Thick Chukchi sea ice stands in contrast to thin ice or wide-open seas in other parts of the Arctic.
Shell hopes drilling the "top holes" will allow it to get back on track and still have 10 wells drilled by the end of summer in 2013.
Shell suffered another setback in Dutch Harbor, Alaska, earlier this month when one of its exploration ships, the Discoverer, drifted toward shore and nearly grounded.
Drilling opponents say the recent problems show why Shell's plans are too risky.
"As Shell Oil continues to push to drill exploratory wells in our Arctic Ocean this summer, the oil giant is giving us a preview of how disastrous a situation this could be," Kristen Miller of the Alaska Wilderness League said in a statement.
Greenpeace USA questioned whether the mooring system in Shell's barge would be safe. "If the Coast Guard certifies this barge with a mooring system that can’t withstand strong storms, how will Shell handle an oil spill during such a storm," asked Jackie Dragon, the group's lead Arctic campaigner.
More content from NBCNews.com:
- Give us a break from ethanol, drought-hit livestock producers ask EPA
- Prop 8 backers ask Supreme Court to review gay marriage ban
- Bedbugs, energy 'audits' among new top consumer headaches
- Man shoots at police officer in dash-cam video
- Sergeant faces 30 days, demotion over soldier's suicide