Gai Waterhouse says Sydney is in the midst of a cocaine epidemic and nobody is safe from contamination.

Sydney's leading thoroughbred trainer made the comments at a stewards' inquiry into the positive cocaine test returned by her horse Love You Honey at Gosford on April 25, which she said must have happened by accident not intent.

She said she was naive about how prevalent cocaine use was in the community until undertaking investigations sparked by Love You Honey's positive swab.

"I think cocaine is so rife in the community it's in epidemic proportions," Waterhouse told stewards.

"I am vigilant in the way I run my yard but it's almost out of our control to think that people can use urinals or touch a door handle and have it on their hands.

"Nobody has given the horse cocaine. I believe the cocaine got into the horse's system because somebody touched it and it got on their hands."

Waterhouse and her legal team interviewed a number of her staff shortly after Love You Honey returned the positive.

As a result of those investigations they provided stewards with a list of staff who had definitely come into contact with Love You Honey around the time of the positive swab and those who may have.

Staff were also asked if they had ever used cocaine despite Waterhouse's strict no drugs policy.

Three out of 80 staff interviewed admitted they had used cocaine at some stage but Waterhouse and her team only provided stewards with details for one, licensed stablehand rider Roy Storch who attended the inquiry.

Stewards adjourned the matter until Friday to consider if they need to speak to the remaining two staff.

Waterhouse said their details were not given to stewards because it wasn't believed either came into contact with Love You Honey or took cocaine around the time in question.

Storch admitted to using cocaine twice in his life, in November last year and May 7 this year.

Hair samples taken from 10 of Waterhouse's staff for DNA testing were all negative.

A urine sample taken from Storch revealed traces of cocaine but it was below the Australian standard and the sample was deemed a negative.