AUGUSTA — The part-time faculty who teach 45 percent of the courses in Maine’s community colleges will get raises and some job protection as part of their first labor contract.

The Maine Community College System’s trustees on Wednesday unanimously ratified the agreement, which also got the approval of more than 90 percent of the members who voted on it last week, according to chapter president Paul Trahan, who teaches English at Southern Maine Community College.

The adjuncts voted in 2010 to unionize with the Maine State Employees Association-Service Employee International Union, joining a national trend.

Between 125 and 175 part-time instructors have joined the community college adjunct union so far. The union says it represents more than 1,000 adjuncts, but community college spokeswoman Helen Pelletier said there are about 750 teaching in any given semester.

The community college system has about 330 full-time faculty.

“Adjuncts are dedicated people who really enjoy what they do,” Trahan said. “I think nationwide what’s happened is there’s been an effort to unionize so we can actually be paid what we’re worth.”

Part-time faculty made up more than 40 percent of all college instructors nationwide in 2011, according to the American Association of University Professors. That number was less than 25 percent in 1975.

Community and technical colleges were the first institutions to rely heavily on adjuncts, said Adrianna Kezar, a professor at the University of Southern California and director of the Delphi Project on the Changing Faculty and Student Success.

About 20 years ago, four-year colleges began hiring more part-time faculty. Many people thought it was a temporary condition, Kezar said, but it persisted, fueling a nationwide movement toward unionization in the past few years.

“People are realizing this is not a short-term issue. It’s a complete change in the mode of how people are employed,” Kezar said. “People are recognizing that they have to unionize, they have to do something because it’s an untenable position.”

Improving working conditions for adjuncts could benefit students as well, Kezar said, because it’s hard for any instructor to focus on supporting students while working out of a car or worrying about paying the bills.

The SEIU’s campaign to organize part-time faculty, who are typically employed for a semester at a time with no benefits, includes ongoing efforts at colleges in Boston, Philadelphia, Los Angeles and other cities.

Most adjuncts in Maine’s community college system earn between $1,500 and $2,500 per course, according to information provided by spokeswoman Helen Pelletier.

Some teach one class at a time as a supplement to another job, while others cobble together full-time work by picking up multiple classes in a semester. Trahan said adjuncts’ pay is much lower than that for full-time faculty, even though the reponsibilities and time commitment are often the same.

The adjuncts negotiated with the community college system for about two and a half years before coming to a tentative agreement in December.

Linda McGill, the system’s chief human resources officer, said it was a complicated negotiation process because each of the seven colleges pays adjuncts in a different way — some by course, some by credit hour, some with higher rates for in-demand technical specialities — and the need to preserve flexibility for the colleges.

“The key to adjuncts is to reach out and touch them when you want them,” McGill told the trustees Wednesday.

The contract includes a cumulative 8 percent raise between 2012 and 2015, plus a one-time payment of $50 for each course taught in 2013-14, up to a maximum of $250. The percentage raise is essentially matches those in the latest contracts for the system’s other bargaining units, McGill said.

The adjunct contract sets up discipline and grievance procedures, provides for some limited seniority in assignment of courses and states that adjuncts will be paid 10 percent of the pay for a course that is cancelled or reassigned to a full-time instructor at the start of a semester.

“I think both sides did a great job in this contract, preserving and advancing the things that were most important to them,” McGill said.

Adjuncts will also gain a new voice in decision-making at the colleges where they’ve lacked representation on campus committees, Trahan said.

Both Trahan and McGill said the negotiations were professional and respectful.

Full-time faculty in both the community college system and the University of Maine System have long been unionized, as have adjuncts in the university system.

Pelletier said the number of adjuncts has remained relatively unchanged for a few years, but there is no good historical data on their numbers or the share of courses they’ve taught.

Systemwide, adjuncts teach about 45 percent of courses. It’s higher at some of the colleges: 58 percent at Southern Maine Community College in South Portland, for example.

Susan McMillan — 621-5645 smcmillan@centralmaine.com Twitter: @s_e_mcmillan