Workers were evacuated from Communications Wireless Group, a company that refurbishes cell phones, on Wilbur Place.
Suffolk County police say authorities were called to CWG Communications in Bohemia at 12:30 Thursday afternoon.
A spokeswoman for Stony Brook Hospital said 54 adult patients were transported to the facility. The patients reported nausea and minor respiratory complaints including shortness of breath. All 54 were treated and stabilized.
The chemicals were said to be two cleaning agents that were inadvertently mixed.
The investigation is continuing by the Islip Fire Marshall.