South Wales Fire and Rescue Service say the location of the fire is different from the blaze at the SiteServ Recycling Centre earlier this month.
86 firefighters are currently on site dealing with the fire and preventing any spread to the surrounding properties.
As a precaution, we ask the public and local businesses to be vigilant, as we move the necessary resources we require, around the site and utilise the water supplies we need.
It has been confirmed that there is no asbestos within the building but we also ask that people keep their windows and doors closed.
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Showers expected throughout the day especially in the north. Drier and brighter elsewhere but cooler than in recent days.
Most places will become dry overnight, although it will remain generally cloudy with patches of hill fog.
Police have told people in Pontypridd that the cordon around the rugby club could be in place until next week.