More than 100 of them died last year from exposure.
Any risk from exposure will eventually become clear, he said.
"Your own student died from exposure to the first one."
A search party found him the next day, dead from exposure.
Another aid group said one of the women died from exposure.
"How long would it take for someone to die from exposure?"
And more than 600 people died on the whole border last year from exposure to heat or cold.
The patients were followed for an average of 42 months from their initial 90-day exposure.
Up to 300 of them died later from burns or exposure.
Q. But did you learn anything from your exposure to them?