At least 52 drug cases involving cocaine are under scrutiny after state health officials in Rhode Island disclosed an incident at a state lab that revealed cross-contamination of test samples. The incident involved a routine quality assurance test at the Forensic Drug Chemistry Lab, which established that a laboratory scientist had reported trace amounts of cocaine that wasn’t present in the sample. State health lab director Glen Gallagher said that the cocaine had carried over from a previous sample. An investigation is ongoing, and health officials have ruled out 549 cases as they didn’t involve cocaine, discounted 436 cases as they involved high cocaine volumes, and are subjecting 52 cases that had lower levels of cocaine to closer scrutiny. The investigation could create problems for prosecutors, who rely on drug lab evidence to secure convictions, and could give a possible advantage to defense attorneys. The lab scientist in question has been removed from testing drug cases involving cocaine until retrained.