THE Obama administration's decision to ignore what it does not know about the hazards of drilling for oil in the Arctic invites trouble.

After the Deepwater Horizon disaster in the Gulf, the president pledged to curtail offshore drilling until more was understood about the accident, and the complexity of oil and gas development in fragile environments.

All that abruptly changed with the Bureau of Ocean Energy Management, Regulation and Enforcement giving conditional approval to Shell Oil to proceed with four exploratory wells in the Beaufort Sea. Additional permits are required but drilling could start by the summer 2012. Drilling in the Chukchi Sea is on the industry's radar as well.

Nothing has changed since Sen. Maria Cantwell's cogent observation last winter, as she reintroduced legislation to permanently ban drilling off the West Coast:

"One of the lessons learned from the disastrous BP oil spill is that without a fundamental transformation of the oil industry, another spill is possible, even likely."

The administration and Congress cannot point to any information to bolster the public's confidence about the industry's ability to prevent a catastrophic accident or the improvement of spill response in harsh conditions. Containment plans exist on paper.

More needs to be understood beyond the raw accumulation of data. A recent study by the U.S. Geological Survey emphasized the importance of subtle impacts on mammals and offshore and onshore ecosystems.

Canada's National Energy Board produced a report with cautionary reminders about operational limitations on spill response from high winds and seas, ice and limited visibility from aircraft in the best season.

The passage of time has not improved the ability of the U.S. government to oversee oil drilling in challenging conditions, understand all the environmental risks or ensure an effective response to a catastrophe.