The  explosion of a Russian Proton Briz-M upper stage last October resulted in a huge debris field in orbit: Upper Stage Explosion Places LEO Satellites at Risk –  Space Safety Magazine

The explosion of a failed launch vehicle upper stage on 16 October created thousands of new debris which pose collision risks to hundreds of  satellites operating in low Earth orbit (LEO), including the International Space Station (ISS).  Fortunately, the threat will be relatively short-lived with the majority of the debris expected to reenter the atmosphere within one year.