The suits were orange Racal suits, designed for field use with airborne biological agents, and they were the same type of suit t

hat had been used at Kitum Cave – in fact, some of them had come back from Africa in Gene Johnson's trunks. The suit has a clear, soft plastic bubble for a helmet. The suit is pressurized. Air pressure is supplied by an electric motor that sucks air from the outside and passes it through virus filters and then injects it into the suit. This keeps the suit under positive pressure, so that any airborne virus particles will have a hard time flowing into it.
–The Hot Zone,
Richard Preston
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