The flame was spotted in the small hours of the night Ernesto passed from Charleston, when technicians were restarting operations following a precautionary shutdown at the plant, which makes phosphorous-based chemicals for the pharmaceutical industry.
Technicians were checking the levels of pentane and ethanol and the absence of water in the unit when they noticed the flame nearby.
Warning sirens went off all around the area and all employees were evacuated with no injuries, while fire fighters brought the blaze under control two hours after it started.
An investigation is under way to establish the cause of the fire and Rhodia did not comment on the impact the incident had on the plant's operations, though a fire officer was quoted in the local media as saying that the fire did "a good bit of damage."
In 2004 South Carolina's State Chamber of Commerce named Rhodia's plant in Charleston as its small-sized "Manufacturer of the Year" among companies headquartered outside of South Carolina.
The award cited the improved and consistent quality of the plant's chemical products, its environmental stewardship, its community involvement and partnerships, and quality of life for its 170 employees.