BRUNSWICK — Democrat John Richardson announced today that he was withdrawing from the race for governor.

His decision was precipitated by the notification last week by the Ethics Commission that three of his campaign workers, most of whom were volunteers, had not followed proper procedures in collecting $5 donations to qualify him for Maine Clean Election funding.

Richardson, former commissioner of the Department of Economic and Community Development and a former speaker of the House, said two of the workers had notified him about possible mistakes roughly two weeks ago. He immediately reported that to Ethics, Richardson said today.

He learned about the third worker with problems last Thursday from Ethics, he said.

“In some cases, there may have been honest, stupid mistakes,” he said. “In other cases, there may not have been.”

Richardson said there were 180 “tainted” $5 donations collected by the three workers. Richardson said he was confident that his campaign could have proven at least 80 of those were not tainted, qualifying him for funds. But the appeal process would take time and distract him from the campaign. Getting $400,000 in Clean Election money late would be a waste of taxpayer money, he said.

He addressed a group of media and campaign supporters, his voice breaking at times as he spoke.

“This is the hardest decision I’ve ever had to make,” said Richardson.

Four Democrats and seven Republicans remain in the primary race.