Hours before a community meeting to mull the best use of money from Suncor Energy’s $9 million legal settlement for air pollution problems at its oil refinery north of Denver, a boiler inside the refinery failed Thursday, leading to flaring and elevated emissions that prompted an emergency response. Suncor managers notified Colorado health officials and local leaders that the company was conducting air monitoring to measure pollutants in nearby communities after the event “resulted in flaring and emissions exceedances.” “As we stabilize and bring the units back online, there may be additional flaring and emissions,” a Suncor bulletin said. The refinery along Sand Creek in Commerce City has been plagued with pollution problems, and the evening meeting was designed to hear residents’ views on possible environmental improvement projects using a $2.6 million share of the money Suncor paid the state following prior violations of pollution limits. Suncor’s 80-acre industrial site is one of about 65 refineries in the nation that process more than 100,000 barrels of crude oil a year.