Medical waste being dumped in hospital car parks could spark an environmental disaster, the boss of the firm at the centre of the NHS disposal scandal claims.

NHS workers are storing bags thought to contain human tissue and used adult nappies in wheelie bins and shipping containers after Healthcare Environmental Services was stripped of 15 contracts.

But HES managing director Garry Pettigrew warned: “This is not how medical waste should be stored. It’s a big public health problem.” The Government brought in the £1million contingency plan after penalising HES for stockpiling waste.

Removal has now been taken over by another private firm, Mitie, Health Minister Stephen Barclay announced.

The Department of Health and Social Care insisted the waste is not infectious or a risk to the public.

Workers moving waste at St James's hospital in Leeds

Our photos show porters moving waste in bins and roll cages normally used to carry bed linen. Mr Pettigrew said the waste should be removed by specialists immediately in purpose-built containers.

He said: “You’ve got bags being handled here that will leak bodily fluids and excrement in bins and open shipping containers.

“These are getting the rainfall and will be getting into drainage systems.”

Video footage shows NHS staff in full body suits at St James’s University Hospital in Leeds putting waste in shipping containers. Calderdale Royal Hospital in Halifax, Leeds General Infirmary, Airedale General Hospital, West Yorks, Huddersfield Royal Infirmary and Bradford Royal Infirmary are also hit.

It is understood human limbs are not stored in the makeshift dumps. The Environment Agency is carrying out a criminal investigation into HES after it breached permits for how much waste it could hold at its depots.

Healthcare Environmental Services boss Garry Pettigrew

HES blamed cuts to incinerator capacity and new demand following the introduction of zero landfill waste policies. It comes after documents emerged from officials dated earlier this year warning of a lack of capacity.

Mr Pettigrew said: “We are working with an ageing infrastructure. The reality is no-one has invested in this infrastructure in 40 years.”

But a spokesman for the Environment Agency said: “It’s not true to say there is insufficient incinerator capacity. Our inspections show the rest of the sector is performing well.”