Former Essendon performance scientist Stephen Dank says coaches at the AFL club took supplements last year which would have breached the World Anti-Doping Agency (WADA) code had they been taken by players.
But he says players took nothing that breached the code and Bombers coach James Hird, high performance manager Dean Robinson and club doctor Bruce Reid had detailed discussions with him as he was implementing the program.
The Bombers are being investigated by the AFL and the Australian Sports Anti-Doping Agency (ASADA) to determine whether players used prohibited performance-enhancing drugs, possibly unknowingly.
Dank, who has previously worked with other AFL and NRL clubs, including a successful five-year stint with NRL club Manly, admits he supplied Bombers players with several peptides.
But he said the only supplements applied intravenously were vitamins B and C.
Dank also said he was interviewed by Australian Crime Commission (ACC) representatives last September and they told him they thought he had done nothing wrong.
Dank said coaches and club management were kept fully informed of his program, although they were not present for every part of it.
"Certainly there was a collective involvement," Dank told the ABC's 7.30 program.
"It wasn't just Stephen Dank, even though he managed the program.
"There was certainly an input from people outside of myself structuring that program.
"There was a significant involvement from Dean (Robinson), as the high performance manager.
"But in saying that, there was always detailed discussion with the head coach James Hird. There was certainly detailed discussion with the club doctor (Bruce Reid)."
Dank said he was surprised by allegations the players might not have known what they were taking, as they were kept fully informed.
"Often times, particularly in the early stages, we'd get them to reaffirm that they knew what they were taking and knew what they were doing. There was a lot of discussion with the players on that," he said.
Asked whether he injected any Essendon players with a prohibited substance, Dank said: "No." Asked whether he breached any WADA rules, he again said: "No."
He said players had been administered peptides, but that was a broad term and taking them was not illegal.
"Even within the protein powders themselves there could have been anywhere from maybe three to four different peptides that were part of the ingredients," Dank said.
"By definition a peptide is anything that strings more than two amino acids together, so certainly a lot of these formulations would have had various amounts of peptides within their formulation.
"But again all very legal and certainly all within the constraints of WADA."
But he said that was not the case with everything taken by some of the club's coaches.
"To be perfectly honest, there were a couple of coaches that were using some supplements, if you like, that were a little bit outside the WADA code," Dank said.
"But again they were entitled to it. There's certainly nothing illegal there."