Four workers died and 645 were injured in construction accidents across the East Midlands in a year, the Health and Safety Executive (HSE) has said.
The 2009-10 figures have been released as the HSE begins a series of unannounced visits in Lincoln, Northampton, Leicester and High Peak.
Inspectors will focus on maintenance, refurbishment and repair sites, which is where most accidents happened.
Working at height and asbestos exposure are among the main concerns.
In last year's campaign about a third of all the construction sites visited - in Lincolnshire, Nottinghamshire and Derbyshire - failed safety inspections.
Across 145 sites, inspectors issued more than 45 enforcement notices requiring contractors to either change the way they were working or immediately stop dangerous work.
In two cases, workers were found to be unsafely removing structural parts of buildings, and were not wearing suitable equipment to prevent them falling.