It's too soon to lay blame for the fast-moving fire that killed six in south Minneapolis on April 2. Fire investigators say it will be another week or more before a cause can be determined.

But it isn't too soon to raise questions about some inspection practices that the fatal fire uncovered. Even if code violations were not the source of the blaze, it's worthwhile to reexamine safety and prevention procedures.

Three children and three adults died when fire destroyed McMahon's Pub at 30th and Lake Streets. The victims were in one of six second-floor apartments above the bar. Several Star Tribune news stories since the fire have brought attention to potential inspection problems.

Although the tavern had been cited for fire code violations as recently as March, the upstairs rental units had not been evaluated by the city for at least 16 years. That shouldn't happen and should never be repeated.

Sixteen years passed between reviews because of a city inspection backlog that stems from the last system overhaul. Following a fire in an overcrowded house nearly 20 years ago, the city cracked down on negligent landlords by using licenses that required passing a fire safety inspection. Because of the volume of work that policy added, 10 years later the city was so far behind inspectors estimated it would take 15 to 17 years to finish just the first-round check of thousands of buildings.

So in 2003, to speed up inspections and prevent some firefighters from losing jobs due to budget cuts, some of the review work was moved from city inspectors to the Fire Department. That gave the department responsibility for nearly 3,000 rental properties, including more than 47,000 rental units.

When the Fire Department took over, officials set a goal of getting to all buildings at least every five years, thereby accomplishing in five years what had not been done in the previous 10. The Lake Street apartments that went up in flames April 2 were scheduled for inspections in July. Fire officials have inspected 2,967 building since 2005; the units that burned were among the 259 structures they planned to visit by the end of the year.

Even though the department is making good progress on closing the backlog, it's worth asking if a five-year cycle is good enough. News stories have also raised questions about the quality of inspection training received by fire officials. Fire Department leaders say that their staff receives the same training and refresher courses as regulatory staffers and that a lot of "on the job training" occurs. But two captains told reporters they feel poorly prepared to check for violations.

Even before this month's fire, a review of the split inspections function was underway. City Council members expect the results of that study in the next few weeks. And fire officials say they are working on a plan to adopt a tiered system of inspections, similar to what is done in St. Paul. Under that system, buildings that have had violations are inspected more regularly. Buildings with cleaner records would be visited by the city only every four or five years.

Devastating fires often trigger evaluations of prevention and inspection programs. Let's hope questions raised by the horrible April 2 apartment fire in Minneapolis will lead to improvements in the inspection system that can prevent more such tragedies.