A majority of baby food contains toxic heavy metals that can affect brain development, a disturbing new investigation has found.

Tests of 168 baby foods from 61 brands spanning big names to niche ones found heavy metals in 95 percent of them, according to the report published Thursday.

One in four baby foods contained all four metals assessed by the testing lab, which included arsenic, lead, cadmium, and mercury.

“Even in the trace amounts found in food, these contaminants can alter the developing brain and erode a child’s IQ,” reads the report, which was commissioned by Healthy Babies Bright Futures, an alliance of nonprofit organizations. “The impacts add up with each meal or snack a baby eats.”

The investigation found that 9 foods — just 5 percent tested — did not contain any heavy metals, while 40 percent of the baby food tested contained three different heavy metals.

Of the baby food tested, 73 percent contained arsenic, 94 percent contained lead, 75 percent contained cadmium and 32 percent contained mercury.

The investigation also found that foods with the highest risk included infant rice cereal, rice dishes and rice-based snacks.

“These popular baby foods are not only high in inorganic arsenic, the most toxic form of arsenic, but also are nearly always contaminated with all four toxic metals,” the report said.

The report recommended that the Food and Drug Administration “establish and finalize health-protective standards for heavy metals, prioritizing foods that offer the greatest opportunity to reduce exposure, considering additive effects of the multiple metals detected in foods, and explicitly protecting against neurodevelopmental impacts.”