A chemical used in rocket fuel and fireworks is also found in an array of food products, particularly those popular with babies and children, according to findings released Wednesday by Consumer Reports.

The tests by the advocacy group come decades after the chemical, called perchlorate, was first identified as a contaminant in food and water. The Environmental Working Group in 2003 found perchlorate in nearly 20% of supermarket lettuce tested.

Linked to potential brain damage in fetuses and newborns and thyroid troubles in adults, perchlorate was detected in measurable levels of 67% of 196 samples of 63 grocery and 10 fast-food products, the most recent tests by Consumer Reports found. The levels detected ranged from just over two parts per billion (ppb) to 79 ppb.