But many of them had an advantage: They wrote the tax breaks into law or voted to award millions of tax dollars to energy companies in which they were invested.
Some of the officials began taking the tax breaks before they were elected and continued doing so after taking office. Others used the breaks only after voting on them, according to records reviewed by The Associated Press.
The mingling of personal and political matters has caused a backlash against biofuels at the Missouri Capitol. Senators have endorsed a measure requiring elected officials to divulge on financial-disclosure reports whether they or their relatives received tax credits. A House committee has backed a similar bill.
"If these guys are investing their money in their plants and being part of the value-added agriculture process, wonderful," said Sen. Brad Lager, a Republican candidate for treasurer. "The state of Missouri is heavily subsidizing that, and I just think it's good government to put that information on the table."
Lawmakers who took the breaks defend their actions, saying elected officials are no less entitled to the tax credits than other taxpayers.
Republican Rep. John Quinn and his wife began taking advantage of the tax breaks before he was elected to the House in 2001. After he was elected, they received more than $170,000 in tax credits for investing in ethanol factories, biodiesel plants and various agricultural cooperatives.
During that time, Quinn voted to award $80 million in incentives to ethanol and biodiesel plants. Some of that money went to facilities in which he is part owner. He also backed a 2006 law requiring gas stations sell an ethanol-blended fuel.
Quinn acknowledges the tax credits amount to "a lot of money." But he added: "This is my livelihood. I was a farmer before I was a state legislator, and continue to be a farmer. I really don't feel that farmers should be held to a higher percent of scrutiny than what other legislators are."
Quinn noted that other lawmakers frequently vote on legislation related to their private-sector jobs. Lawmakers who are medical professionals, for example, have been some of the biggest supporters of revamping the state's Medicaid system and increasing state Medicaid payments to health care providers.
House rules excuse members from voting on bills if they have "a direct personal or pecuniary interest" in them, but such decisions are left to each lawmaker. Just two lawmakers invested in ethanol plants excused themselves from voting on Missouri's ethanol mandate.