Effective Jan. 1, a new Maryland law will require a bitter-tasting additive be put in antifreeze, which can kill people and animals who drink it.

The law was co-sponsored by Dels. Peter F. Murphy (D-Charles) and Jon S. Cardin (D-Baltimore County), who took up the cause of a Huntingtown woman. Lynne Gillis testified at a legislative hearing last winter about her hound-mix dog, Nikko, who died after ingesting antifreeze.

Gillis had rescued Nikko from the Tri-County Animal Shelter in November 2006 after he was found wandering around Dares Beach Road.

On Feb. 17, Gillis said Nikko was vomiting and not acting normal — he was stumbling was lethargic. She took him to the Anne Arundel Animal Hospital, where he tested positive for antifreeze poisoning.

“They told me what it was, and I couldn’t believe it,” she said.

It was too late for Nikko, who died the next day. Antifreeze poisoning needs to be diagnosed within two hours to possibly save an animal, but most don’t show symptoms until after that, she said.

Gillis later learned that someone had thrown a tennis ball laced with antifreeze over her fence and into her yard, where she lets her dogs out. She said that she has an idea who it was but that there is not enough evidence to prosecute.

Gillis said that because she was unable to get justice for Nikko in the courts, she turned to helping get a law passed.

With Nikko’s poisoning fresh in her mind, Gillis, who volunteers at the Calvert Animal Welfare League, testified March 4.

“Nikko’s death is not in vain,” she said. “This is a victory for me; this is part of my healing.”

Murphy and Cardin sponsored the legislation after researching the effects of ingesting antifreeze. They learned that it has killed animals and people both accidentally and on purpose.

“It’s so sweet-tasting,” Murphy said, and “it requires a very little bit of it to kill.”

In February, an Alabama couple killed their two children by putting small amounts of antifreeze in their food.

Murphy asked Gillis to testify after learning her story, saying she brought the bill to life for lawmakers.

“Lynn Gillis gave what I consider a riveting, compelling and an emotional testimony,” said Del. Anthony J. O’Donnell (R-Calvert).

“It was clear that there was a need for this bill,” he said.

The Maryland Antifreeze Bittering Agent Act, which requires retailers to stock engine coolants with the additive denatonium benzoate, will take effect Jan. 1. Initially the law was to begin Oct. 1, but lawmakers agreed to a later date to allow retailers to clear their inventory.

“So many times [retailers] have to order ahead, we felt that it was a fair compromise,” Murphy said. Manufacturers have said that the bitter agent adds about 2 cents to the cost of a gallon of antifreeze, he said.

Maryland is one of 17 states that have passed legislation requiring the additive, according to the American Veterinary Association.

Gillis received a pen in the mail that Gov. Martin O’Malley (D) used to sign the bill into law.

“It was very cathartic for me,” she said.