Eye-witnesses reported at around 11am that Armthorpe Road Recycling Centre was closed off with a heavy police force at the scene.
Staff were locked outside the site following the incident as police investigated after rumours began to circulate that live mortar shells had been dumped there.
However, South Yorkshire Police said that the items were commercial grade fireworks and there was no risk to the to the community.
Officers disposed of the fireworks and the site has been reopened.