More than 100 students have no Student Service Learning hours beyond the 20 they earned by completing activities in the Life Skills class, required for all sophomores, he said.
The numbers are alarming since students who don't turn in the required 75 hours - earned through various types of volunteer work - before the end of the school year will not have a chance to make them up over the summer, said Jacobs.
Students can earn their hours in all kinds of ways, ranging from helping a disabled neighbor perform chores to volunteering at a national park, he said.
However, the activity must be pre-approved and students must go through a three-step process - preparation, action and reflection - then properly document it in order for the hours to count, he said.
Ignorance of the requirement and a busy schedule are no excuse, since the class of 1997 has been aware of the requirement for the past four years, he said.
Students have heard about the requirement during assemblies, in repeated announcements over the public-address system, through posters and hand-outs, and one-on-one, Jacobs said.
They've also been kept informed about specific service opportunities, he said.
Parents were sent letters informing them about the requirement and updating them on their child's progress, he said, and stickers showing the number of hours remaining have been put on report cards.
Still, some students either don't believe they won't graduate without the hours or are just plain putting it off, Jacobs said.
"I just don't think students are aware of how critical it is and how little time they have," he said.
North Hagerstown High School senior Bob McMurphy said he isn't concerned about the roughly 45 hours he still has to earn.
"I'm planning on doing the rest. I just haven't gotten the time," said McMurphy, 17, who said he hasn't decided what he'll do.
High school principals, like North High Principal David F. Reeder and Career Studies Principal Arnold Hammann, aren't taking a relaxed attitude, however.
"Our goal is to get every student to graduation," said Reeder, who had nearly 46 percent of students in jeopardy as of Jan. 17. "It would be a real tragedy for any student not to walk across the stage because they haven't met the 75-hour requirement."
The numbers have improved since late September, when about half of the county's seniors still hadn't completed their hours, Jacobs said.
Only one school - Hancock Senior High School - has a clean bill of health on the requirement, he said.
While many are holding off until the last minute, others completed their requirements, or exceeded them, some time ago, Jacobs said.
North High senior Stacy Hott hasn't had to worry since her freshman year, when she finished her required hours in anticipation of a busy schedule.
"I have sports and everything, so I wanted to make sure I had them out of the way so it wouldn't interfere with sports and school," said Hott, 17, who put in her hours at a nursing home, in the kitchen of a church camp and at a food pantry.
A bill giving local school boards the option of making Student Service Learning a graduation requirement was introduced in the Maryland General Assembly on Jan. 20.