(Portland, OR) -- Fire officials say a hash oil explosion caused the fire that killed two people and destroyed a home in North Portland Monday. Portland Fire and Rescue said the explosion happened when a large concentration of butane ignited. The butane was being used to produce butane hash oil. The explosion killed 42-year-old Matthew McCrann and 68-year-old Richard Cisler. A firefighter suffered minor injuries and two other homes were damaged.