BISMARCK, N.D. – Cindy Sanford has worked in big cities but it wasn’t until she landed a job in North Dakota’s booming oil patch hub of Williston that she began worrying about her safety.

Now, the 55-year-old single woman has a concealed carry permit and is shopping for a handgun. She’s among a burgeoning group of residents authorized to pack a weapon in North Dakota for self-defense.

“I did it out of awareness,” said Sanford, who also takes other precautions, such as altering her daily commute to work at the Job Service office in Williston.

The number of concealed carry permits in North Dakota has more than tripled in the past decade, to more than 16,000. State Bureau of Criminal Investigation records show the agency issued almost 5,500 concealed carry permits in 2011, up 40 percent from the year before. Williams and Ward counties in western North Dakota had about 1,300 concealed weapons permits issued last year, or about 50 more than in Burleigh and Cass counties, which are the state’s most populous counties and located outside the oil patch.

Sanford said she never considered carrying a handgun when she lived in Atlanta and Denver.