Heat waves, droughts, extreme weather events, and other environmental stresses associated with climate change are triggering plants to produce toxic chemicals at levels that can be harmful to human health, concludes a report from the United Nations Environment Programme. Under ideal growing conditions, plants turn nitrate into amino acids and protein. But under drought conditions, the conversion slows down and nitrate accumulates in the plant. Cattle, sheep, and goats can be poisoned from eating plants with high nitrate levels, leading to miscarriage, asphyxiation, and death. In people, particularly infants, nitrates are linked to a disorder that decreases the ability of red blood cells to release oxygen. When some water-stressed plants are later irrigated or receive sufficient rain, they make another toxic compound—hydrogen cyanide (HCN), also known as prussic acid, the report says. Apples, peaches, cherries, cassava, corn, and other crops are known to accumulate HCN. The report also finds that climate change is associated with a rise in mycotoxins, by-products of fungus that are linked to developmental problems in infants, decreased nutrient uptake, and suppressed immunity.