Randwick trainer Ron Quinton and country-based Group I-winning trainer Gordon Yorke face seperate stewards' inquiries over cobalt positives returned by gallopers from their stables.
Quinton has been asked to front an inquiry after "certified findings from two official racing laboratories" confirmed the cobalt above the legal threshold were detected in a pre-race urine sample taken from Boss Lane.
The sample was taken from the gelding prior to his fourth placing in the Group II Missile Stakes on August 5.
"Stewards have ordered the analysis of feed and supplements taken from Mr Quinton's stable," the stewards' report read.
"During the course of the investigation Racing NSW Stewards have taken some 35 out of competition samples from horses trained by Mr Quinton to endeavour to ensure that horses presented to race are done so in accordance with the Rules of Racing."
The inquiry into the matter will be held at a time and date to be fixed.
Meanwhile, Victoria Derby-winning trainer Gordon Yorke is also facing a cobalt inquiry after Follow Through returned an elevated reading in the pre-race urine at Grafton on July 13.
The five-year-old mare finished second in the Bidfood Class 1 Handicap after easing from $8 to $21.
Stewards have also ordered analysis of Yorke's feed and supplements taken from the stable.
" An out of competition sample taken from Follow Through prior to racing at Gosford on 17 August 2017 confirmed a level of cobalt below 100ug/l," the stewards report read.
Yorke also faces an inquiry at a time and date to be fixed.
