Photographs of clinical waste bags accumulated in three health centers in northern Lanarkshire have been published on social media.
NHS Lanarkshire said the waste had been removed and posed no risk.
Following the collapse of HES in December, the Scottish government said emergency plans would ensure that clinical waste continues to be disposed of safely.
NHS National Services Scotland also stated that "appropriate emergency measures" were in place to process clinical waste after HES lost its service contract.
However, a former employee of HES, who asked not to be named, said: "The companies that took over the collections are working at full speed, but there is no Eks and weeks of waste incurred. "
The images of the three Lanarkshire sites, which reportedly were taken this week, appeared on a Facebook page created by those who said they were worried about the HES situation. The images have been removed.
John Paterson, director of property and support services at NHS Lanarkshire, said. "The waste from the Coatbridge, Kilsyth and Central health centers (in Cumbernauld) were raised between 9 and 11 January.
" We have an interim process agreed to ensure that clinical waste is lifted as and when requested, while the national contract is terminated.
"There has been a delay in uplift requests with these three centers, but in the future we have taken steps to avoid it: it was low-level clinical waste that was collected according to procedures and kept in closed areas. 39; there was no risk to public health. "
Appropriate protective equipment
A spokesman for the health commission was unable to confirm exactly how long the waste was lying in the sites.
HES, based in Shotts, lost its contract to provide waste treatment services to NHS England, following the news that emerged in October of last year that parts of the human body and other clinical waste they were accumulating after the company struggled to incinerate it.
NHS Scotland announced that the company would not keep the contract north of the border when it was renewed by April.
Since then, the company has served hundreds of dismissal notices and has not paid the salaries of 350 employees for December.
In Inverness, four carriers of the Raigmore Hospital were injured by carrying out work involving clinical waste.
The site's known carriers played a major role in treating the material after the collapse of HES.
A spokesman for the Scottish government said: "We consider the safety of all NHS employees to be essential.
agreements recently introduced throughout the country have been assessed and identified with safe security systems, with appropriate protective equipment released and made available to all staff. "