OMAHA, Neb. (AP) _ New federal standards for shipping crude oil by rail will have a significant impact on Berkshire Hathaway’s BNSF railroad and its Union Tank Car business.

Berkshire CEO Warren Buffett says he hasn’t studied the rules closely yet because they were announced last week _ just before his annual shareholder meeting.

Buffett says railroads play an important role in transporting potentially dangerous products across the United States, and he thinks it makes more sense for railroads to haul them instead of trucks or pipelines in most cases.

Buffett says Fort Worth, Texas-based BNSF and other railroads are working to improve safety, but it’s impossible to ever be 100 percent safe.

There have been several fiery derailments involving crude oil trains this year, but those have all happened in more rural areas.