NDstatecapitalBISMARCK, N.D. (AP) – Some North Dakota lawmakers are taking on a sobering tone as crude oil prices slipped to a more than five-year low Monday and below a threshold that could threaten billions of dollars of oil tax revenue for the state.

The chairman of the Senate Finance and Taxation Committee says oil prices are the biggest concern for lawmakers for the 2015 Legislature, which begins Tuesday.

Sen. Dwight Cook, of Mandan, calls tumbling oil prices a “big, black cloud hanging over the session.”

Senate Democratic Minority Leader Mac Schneider, of Grand Forks, says it’s the first time in years the Legislature has had to consider the prospect of low oil prices. He says the state must look at carefully at spending while making long-term investments on such things as education.