LANSING, Mich. — One frustrated client hurled a piece of concrete through the window of a welfare agency. Another threw her car keys at a welfare worker before being escorted away. At one point, a woman on public assistance even took a swing at a worker.

As Michigan struggles with the highest-in-the-nation jobless rate, state workers who deal with unemployment, welfare and other aid programs say they have never been so overwhelmed — or so worried about their safety. Some clients have begun taking their anger out on the very people who are offering help. And caseworkers are seeking extra protection.