A car drives past the U.S. Embassy in Havana in 2019. Dozens of Americans working at U.S. diplomatic missions in Cuba and China in recent years have suffered from ailments that have included headaches, balance problems and memory loss.

A 1950’s era Buick convertible car drives past the U.S. Embassy in Havana, Cuba, Sunday, March, 17, 2019. (AP Photo/Pablo Martinez Monsivais)