Georgia Code Title 34. Labor and Industrial Relations § 34-9-17

(1) If the amount of alcohol in the employee's blood within three hours of the time of the alleged accident, as shown by chemical analysis of the employee's blood, urine, breath, or other bodily substance, is 0.08 grams or greater, there shall be a rebuttable presumption that the accident and injury or death were caused by the consumption of alcohol;

(2) If any amount of marijuana or a controlled substance as defined in paragraph (4) of Code Section 16-13-21, Code Sections 16-13-25 through 16-13-29, Schedule I-V, or 21 C.F.R. Part 1308 is in the employee's blood within eight hours of the time of the alleged accident, as shown by chemical analysis of the employee's blood, urine, breath, or other bodily substance, there shall be a rebuttable presumption that the accident and injury or death were caused by the ingestion of marijuana or the controlled substance; or

(3) If the employee unjustifiably refuses to submit to a reliable, scientific test to be performed in the manner set forth in Code Section 34-9-415 to determine the presence of alcohol, marijuana, or a controlled substance in an employee's blood, urine, breath, or other bodily substance, then there shall be a rebuttable presumption that the accident and injury or death were caused by the consumption of alcohol or the ingestion of marijuana or a controlled substance.