Hundreds of employees of the Eastern Cape health department have been issued with final warnings aft.
Saids CEO Khalid Galant said a more detailed statement would be issued later on Friday confirming the 29-year-old had been cleared of charges after failing a doping test in February.
"This is the best news to give to all my family, friends, team and fans," the cyclist tweeted on Friday.
Impey, who made history last year as the first ever African to wear the yellow jersey in the Tour de France, tested positive at the SA Road Championships for the prescription diuretic Probenecid, a substance which can be used as a masking agent.
Orica-GreenEdge removed Impey from their Tour de France line-up this year as soon as the Australian team was notified that Impey had delivered a positive A and B sample in South Africa.
"While I never disputed the lab results and the finding, I was put in a very tough position of defending my case due to strict liability," Impey said on his website www.darylimpey.com.
"That being said, and after already having to go back five months to try to find out how this could have happened, I finally was able to prove that this was a case of cross-contamination and I was also cleared of any fault or negligence on my part."
He said it had been the hardest two months of his life and had caused him a huge financial loss.
"It has been tough on my whole family. But I was determined to show that I am clean and that I would never cheat to try get an advantage over my competitors. I am so relieved that this has now been proven."