The Arizona Department of Public Safety changed its policy on field-testing suspected narcotics due to fears that troopers could overdose from contact with the potent opioid fentanyl.
The Arizona Republic reported on Saturday that troopers are barred from conducting the tests, so the samples are sent to the department's laboratory.
The newspaper reviewed data from August that indicates the policy change has caused a backlog of more than 2,000 controlled substance cases that still require testing.
Officials say that if the delay is left unchecked, it could hinder prosecutors from filing formal criminal charges.
Because of the controlled substance testing backlog, the department's backlog of all other pending tests has increased.
Some medical professionals question if such a testing precaution is necessary.