In 2011, Prince George's County Del. Benjamin S. Barnes became a partner in one of the state's busiest workers' compensation firms. The lawmaker wrote a three-word disclosure in blue ink on his state ethics forms, and began working on legislation that made it easier for injured workers to win awards.

As he sponsored or co-sponsored workers' compensation bills, his firm's founding partner brought in millions in workers' compensation claims over an 18-month period — raising questions about whether Barnes should be advocating for laws that could help his business.

"It's a serious concern," said Jennifer Bevan-Dangel, director of the government watchdog group Common Cause Maryland. "It's one we can't really rectify as long as we have a part-time legislature. It's hard to avoid these conflicts when your legislators have to get a second job."

Barnes and other legislators defend his work, noting that it falls within General Assembly ethics guidelines.

Barnes sees the 12 workers' compensation bills he's worked on as helping his constituents. He's well versed in workers' compensation issues, he says, and each bill addresses a specific part of the system that could be improved for workers. He added that he is paid a salary by his firm and, therefore, does not directly benefit financially from the legislation.

"This is one of the beauties of the citizen legislature," the Democrat said. "People take their expertise and put them to practice in our assembly."

Local governments in Maryland are concerned about workers' compensation costs, and blame steady increases on a variety of factors, including a higher ceiling on payouts, changes in state law that favor public safety workers and some instances of fraud. Baltimore spent $49 million last year on workers' compensation awards and related expenses such as attorney fees, and officials expect costs to rise for the next decade. Baltimore County, whose workforce is slightly smaller than the city's, paid about $11 million last year.

Three of the bills Barnes has worked on have become law. In 2012, he was the lead sponsor on a bill that made Washington Metropolitan Area Transit Authority police — some of whom are represented by his firm — eligible for enhanced benefits. He also was listed as a co-sponsor on an O'Malley administration bill that aided firefighters by expanding the number of diseases presumed to be job-related.

"This is an unavoidable hazard that firefighters are asked to be exposed to," Barnes said. "I think we owe it to them to take care of them."

This year he's a co-sponsor on three more bills, including one stating that high blood pressure and heart disease are presumed to be job-related ailments for corrections officers. In the past, he also has championed a bill stating that a police officer's back pain is presumed to be caused by wearing a gun belt; that measure has failed to pass.

The state's ethics guide for lawmakers says a conflict of interest is presumed if the legislator has a "direct interest in an enterprise which would be affected by the legislator's vote on proposed legislation." The guide says that a conflict will not be presumed if the "interest is common to all members of a profession or occupation of which the legislator is a member, or to all members of a large class of the general public."

Deadra W. Daly, attorney and ethics adviser for the Joint Committee on Legislative Ethics, said recusal from voting on a bill is only necessary if the legislation has a very narrow benefit for a specific group of people that includes the legislator.

"Everybody has other jobs and other parts of their lives," she said. "We expect [legislators] to bring their background knowledge to their activities here. We expect farmers to vote on farm bills, for instance. We look at the size of the group that's impacted. If there were a bill that would just impact my firm, clearly I shouldn't participate. If we have a bill that's going to affect thousands of law firms and a whole lot of plaintiffs, then we would not require recusal."

Political observers note that state lawmakers frequently work on bills that affect their professions. For instance, Prince George's Del. Joseph F. Vallario Jr., chairman of the House Judiciary Committee, is a criminal defense attorney.

Howard County Sen. Allan H. Kittleman, a Republican who sits on the state workers' compensation oversight panel, has represented companies such as Canada Dry, Sears and Target in workers' compensation cases for the Ellicott City law firm of Godwin, Erlandson, Maclaughlin, Vernon & Daney. This year he has co-sponsored two workers' compensation bills.

Kittleman said he doesn't see anything wrong with working on legislation concerning his industry. He said that the oversight board doesn't make final decisions on bills, and that he would recuse himself if a vote violated state ethics rules.

"If it would help one particular client that I might represent, then I have to recuse myself," he said. "If it's something that affects all people across Maryland exactly the same, there's no reason to recuse yourself."

Bevan-Dangel said Common Cause supports establishing a full-time legislature in Maryland to avoid such conflicts — whether they are real or merely perceived.

Handling cases for injured workers can be big business for attorneys who specialize in the field — with nearly $400 million in payouts ordered by the state Workers Compensation Commission last year. State law allows payouts for medical bills, lost wages and permanent disabilities that can stretch for years.

Lawyers typically get as much as a 20 percent cut of their clients' awards, and one independent analysis listed Barnes' firm — Hall, Butler, Macleay & Barnes, LLC — as the largest workers' compensation practice in Maryland.