Traces of the constituents of penta-BDE only have indeed been found in the environment in areas far from production sites. This is not the case for other BFRs. There was a historic use of penta-BDE in non flame-retardant applications such as hydraulic fluids in mines and oil drilling. These emissive applications took place until the late 1980s and then stopped. This would explain the fact that levels of penta-BDE in the environment have decreased by 30% since 1997.
BSEF Q&A Oct. 2001