Blaming low unemployment, Curtis Graves, an attorney with the Mountain States Employers Council, said if the unemployment rate ticked up to 6 or 7 percent, some employers would likely resume testing for marijuana. But, for now, many Colorado businesses are dropping the drug from pre-employment tests, while some are removing it from all drug tests. Overall, only 62 percent of businesses in the state of Colorado test for drugs, down from 77 percent in 2014. Those industries with the highest percentage of businesses that drug test were mining, utilities/transportation/communication and construction.