Researchers in Boston recently tested imported spices and food products in 15 Indian specialty stores and found a quarter of the samples contained more than 1 microgram of lead per gram, TIME reported yesterday.

The study, published in the journal Pediatrics, was conducted after the lead poisonings of Indian children were linked to Indian spices. The link prompted researchers at Children’s Hospital Boston and the Harvard School of Public Health to investigate whether lead in spices is a widespread problem.

In addition to finding lead in 25 percent of spices sampled, researchers found that, on average, imported spices contain double the amount of lead in U.S. spice brands.

Though most lead levels detected are well below the European Union’s acceptable threshold, the authors of the study believe the trace levels are concerning, as they could add to exposure from other neurotoxins.

The FDA has different thresholds for allowable levels of lead in food

products based on how often a product is likely to be used. Last

summer, the FDA updated its guidance on lead likely to be consumed by small children, significantly lowering the recommended maximum level.

The FDA does not have specific guidelines for screening lead in imported spices.

“We look at imports and we look for lead and other elements,” Ira Allen, a spokesperson for the agency told TIME. “But we do it on a targeted basis, and some of that basis is how the product is intended to be used.”

“We have extensive surveying of imported foods at major ports,” added Allen. “Obviously we can’t look at everything, but we do target inspection based on where the food comes from and what the history of the product is, and we do ban certain products.”

The regulation of imported spices is garnering increased scrutiny. Lead concerns come in the wake of an ongoing Salmonella outbreak tied to imported red and black pepper, which has sickened at least 249 people in 44 states and the District of Columbia.

The recalled pepper was imported from Vietnam, but it is unclear where in the supply chain the contamination occurred. The product was distributed in all 50 states and Canada and over 150 food products were recalled, including 1.4 million pounds of ready to eat meats.