The company signed up to solve Scotland’s may not be able to begin its operation until autumn.
Hundreds of tons of toxic material including body parts, syringes and blood have been stockpiled since the collapse of (HES) in December.
Spanish-based Tradebe has been lined up to take over the work while the Scottish Government relies on “contingency arrangements”.
But Tradebe has said starting the contract before the end of the summer is “dependent on planning and environmental permits being approved”.
A spokesman said: “Planning and environmental permits have been submitted by Tradebe to start the contract on August 2.
“Contract start is dependent on planning and environmental permits being approved, without which NHS Scotland could remain in contingency beyond August 2.”
Under the new contract, “yellow bag” waste from hospitals, containing syringes and other sharp materials, will be sent to Wrexham in Wales.
The plant will also initially process “orange bag” waste, such as items contaminated with bodily fluids, until a plant in Bellshill, Lanarkshire, is ready.
But the Sunday Mail last week revealed opposition to the facility, which would be converted from existing industrial premises at a business park.
Objections have been lodged by Labour MP Hugh Gaffney and Labour MSP Monica Lennon over fears of the impact on residents.
They have also questioned why HES’s existing plant in nearby Shotts is lying dormant and called for an inquiry into the crisis.
Lennon said: “The Health Secretary must confirm the true cost to Scotland’s NHS of the botched contract and the cost associated with any delays to the new contract.
“She’s already explained that emergency plans are expensive so we need to know when normal service will resume.”
A Tradebe spokesman said: “The facility will be close to where 80 per cent of Scotland’s clinical waste is produced, optimising transport routes and minimising traffic noise.
“We are confident that our operations will not result in increased volumes of traffic in the local area.”
Tradebe also insisted that yellow bag waste being transported to Wrexham for high temperature incineration would be “continuing the practice used” as no temperature incineration capacity is available in Scotland.
The Scottish Government declined to comment.
