A North Easy recycling company and its director have been ordered to pay £33,000 after polluting a stream.
The Environment Agency said Adam Metcalfe and his firm AWSM Recycling Ltd failed to notify the incident.
The company stores waste and spreads it on agricultural land for the purpose of land improvement, which is controlled by environmental permits.
The case against the firm and its director involves a number of breaches of environmental law between July 2011 and October 2015.
The charges relate to the illegal spreading of hazardous material on land, unauthorised burning of waste and allowing waste to escape into streams in three separate incidents.
It also involves the spreading of a nitrogen-rich substance contrary to regulations designed to protect the environment from pollution.
John Crowl from the Environment Agency said: “Their neglect led to serious pollution incidents which impacted on nearby streams and killed fish and invertebrates.
“I hope this sends out the message to others that if they fail to abide by environmental laws then we will take action.”