Banned chemical may cause deafness in whales

A toxic chemical used to prevent barnacles from clinging to ship hulls may cause deafness in marine mammals and could lead whales to beach themselves, Yale University researchers say.

The hearing loss would be the latest environmental hazard linked to TBT, a chemical already known to be harmful to some aquatic life. TBT is banned in many countries but is still widely used.

Yale researchers based their theory on a study of guinea pigs, because mammals have similar ear structure.

Since many marine mammals use sonar to get around, "it's possible this could be contributing to whales and dolphins beaching and hitting ships", said Joseph Santos-Sacchi, professor of surgery and neurobiology at Yale School of Medicine.

"I think it's a reasonable hypothesis that this could possibly be happening," said Theo Colborn, a senior fellow at the World Wildlife Fund who has studied TBT but was not involved in the Yale research. "It sounds very logical."

Many scientists also believe the beaching of whales occurs for non-chemical reasons - primarily the Navy's use of sonar.

The Yale study will be published in the Biophysical Journal in March.