Johnson County social worker Teri Zenner was brutally murdered in 2004 by a teenage client during a routine visit to his home.
Since then her husband has fought to require safety training for all new social workers, determined to turn his family's tragedy into something positive.
On Thursday, he and Teri's father celebrated as Gov. Mark Parkinson signed their idea into law.
"What happened to Teri shouldn't happen to anyone," said Matt Zenner of Olathe. "This is huge, and it's a chance to save some lives."
The law requires new social workers to receive at least six hours of personal safety training as part of the 40 hours of continuing education needed for their first license renewal.
Kansas is the first state in the nation to mandate the training, according to Sky Westerlund, a social worker who lobbies for the National Association of Social Workers' Kansas Chapter. The requirement will take effect for licenses renewed Jan. 1 or later.
"We're breaking new ground," she said.
Teri Zenner, 26, was making a routine home visit to a 17-year-old client when he attacked her with a knife and a chain saw, killing her. The attacker, Andrew Ellmaker, was convicted of murder and is serving a life sentence with no chance of parole for 50 years.
Matt Zenner thought his idea was a "no-brainer" when he first approached lawmakers. But it languished on the legislative agenda until a renewed push got it passed this year.
Teri's father, Andy Mathis of Gardner, said he wanted to see social workers required to carry GPS devices or cell phones with a panic button in case they got into trouble. But the new law is a big step forward, he said.
"It means that Teri didn't give her life in vain," he said. "It's been a long time coming."
After her death, her employer, the Johnson County Mental Health Center, instituted several new policies designed to improve social worker safety. All social workers are now required to carry cell phones in the field.
The center created a series of regular, small-group exercises to teach social workers how to identify and respond to risky situations. A checklist to assess the threat of certain clients was created. The center worked with local police to offer self-defense classes.
Also, the center encourages caseworkers to listen to their instincts and to put their own safety ahead of their job, according to David Wiebe, executive director. Wiebe said he supported the new law and thought that it should be expanded to require regular refresher courses on safety.
"We serve probably 10,000 people a year and the vast majority is no threat to safety," he said. "So the first thing was how can we identify the folks we need to pay attention to? Until something like this happens, you probably don't spend as much time thinking about these things as you should."
At the bill signing, Parkinson thanked Teri Zenner's family and friends for not giving up on the legislation despite years of delays. The new law, he said, will be "protecting social workers for years to come."