Capacitor plague

The first flawed capacitors were seen in 1999, but most of the affected capacitors were made in the early to mid 2000s, and while news of their failures (usually after a few years of use) has forced most manufacturers to fix the defects, some bad capacitors are still being sold or integrated into designs in early 2007.
An incorrect electrolyte formula within a faulty capacitor causes the production of hydrogen gas, leading to bulging or deformation of the capacitor's case, and eventual venting of the electrolyte. In rare cases, faulty capacitors have even been reported to pop or explode forcefully.
Not fully verified list of affected brands:

• Tayeh
• Choyo
• Chhsi
• Jackcon
• GSC
• Jun Fu
• Lelon
• Luxon
• I,Q
• JPCON
• A4
• CHOCON

Wikipedia: Capacitor plague