Poly Implant Prothese, the French breast implant manufacturer who was shut down and saw it’s products banned in 2010, has now been found to have been using a fuel additive in its implants, the AFP reports. The company knew the implants were faulty back in 2005. The French government advised French women to have the implants removed as a safety measure at the state’s expense, the Telegraph reported in December. The implants have not been linked to increased incidence of cancer.

The materials used in the implants –Baysilone, Silopren and Rhodorsil– were never approved for clinical use and “allegedly contributed to the silicone gel implants having a high rupture rate.” Health and safety authorities already knew the implants contained industrial, not medical silicone, “but this is the first time the use of petroleum industry additives has been reported.”

The British media reported that PIP’s implants were seven times more likely to rupture than others, prompting a French lawyer for implant wearers, Phillipe Courtois to ask for tests on implants sold in other countries.

The AFP also obtained emails from the PIP sales department showing they knew the shells of the implants were faulty as far back as 2005. In response to one colleague’s concerns about the shells rupturing, a marketing higher up replied “Sales are more important than what the shells are made of.”

Up to 400,000 women in 650 companies have implants “made with the substandard gel.”