Self-contained biological indicator for 270°F/132°C gravity steam cycles consisting of a Geobacillus stearothermophilus spore strip; sealed glass ampule with growth medium and dual indicator system; blue color-coded cap with holes for sterilant penetration and a hydrophobic filter as a bacterial barrier; and a chemical indicator on the label that changes from rose to brown when processed. After sterilization, the vial is "crushed" to join the growth media with the processed spore strip. The BI is incubated for 1 hour in the 3M™ Attest™ 290 series auto-reader for a fluorescent reading. A red light indicates a positive result or sterilization failure.