text: Probably these changes**mirror the structural economic changes**, that is, the shift of workforce 
  between sectors. Night work was common in many industries as part of a three 8-hours shifts, not only 
  in industries with permanent production processes (steel, chemicals, etc.). 27 Moreover night work is and 
  was common in essential services like health, transport, technical infrastructure and security. The 
  
  European Agency for Safety and Health at Work – EU-OSHA 
  32 