A Lincolnshire company and a farmer have been ordered to pay thousands of pounds for causing water pollution.
Sleaford Magistrates Court heard Omex Agriculture, based in Bardney, supplied a storage tank to farmer Richard Applewhite of Barkston Gorse Farm.
Liquid fertiliser leaked from the tank into the River Witham and killed thousands of fish in April 2002.
Omex Agriculture was ordered to pay £47,000 in fines and costs and Mr Applewhite was fined £5,000 with costs.
The Environment Manager from the Environment Agency, David Hawley, said farmers need to take more care.
"It is just so important that they (dangerous chemicals) are stored safely and securely.
"This is the second prosecution in Lincolnshire in the last month that has resulted from the improper storage of chemicals."