Cemex last week received a final warning from government officials for pollution from its Rugby Cement plant. However, the Environment Agency (EA) gave the company the go-ahead to burn tyres as fuel at the site.
The EA issued the warning after Cemex turned a local stream white and kept quiet over dust emissions in incidents at the end of 2004 and beginning of 2005. Polluted water from its Rugby works last Christmas turned a stream white for several kilometres.
The EA said any further offences will have "very serious consequences" for the company. It added: "The most likely outcome is that the company will be prosecuted."