President Trump on Wednesday was poised to sign the new tax bill, passed by Congress, which lifts a decades-old ban on oil and gas drilling in the Arctic National Wildlife Refuge in northeastern Alaska. Here’s a look at what might happen now.

Will exploration begin immediately?

No. Both supporters and opponents say it could be years before the first lease sale, a precursor to any drilling. The new legislation requires that the Department of Interior conduct one sale within four years and a second within seven. But there are many steps that must be taken before those sales can be held, and the process is not completely clear. Lawsuits and other actions by opponents of drilling could slow things, both before and after any lease sales.

The Interior Department will have to identify lands in the 1.5 million acres of the refuge along the coastal plain, known as the 1002 area, for leases. Once the department comes up with a list of options, there will be at least one comment period in which the public will have a chance to be heard.

One question mark is whether new seismic studies will be undertaken. Such studies can reveal underground formations that have high oil development potential, and the only ones that were done in the refuge are more than three decades old.