The concerns, according to six people with knowledge of the matter, come amid a push by the administration to ensure allies are prepared for such an event, as well as to mobilize new resources and investments in manufacturing of detection systems for when the chemicals are used. The people, who spoke on condition of anonymity to discuss sensitive, internal deliberations, include U.S. and Defense Department officials.
The U.S. does not have any intelligence to suggest such an attack in Ukraine is imminent, the people said. In fact, many DoD officials believe the fighting will stall during the winter months, with neither side able to take much ground.