From the MPCA Small Business Enterprise publication:
Compliance calendars make it easier for you to keep proper environmental compliance records. The calendars contain recordkeeping logs for records required by federal and state rules and permits, along with pollution prevention tips.
Calendars have been tailored for the following sectors: hot mix asphalt, sand and gravel, aboveground storage tanks, dry cleaning, vehicle repair, and construction stormwater. A limited number of free paper copies are available. The calendars are also available for download here.