Health and safety and the gig economy offers advice on how to support particular groups, or tackle a specific health and safety issue. It covers workers who are considered to be at greater risk of physical attack, verbal abuse or injury, including porters, care workers, security staff, maintenance workers, community nurses and parking wardens.
It also offers advice on how to protect workers on construction projects who may be on short-term or zero-hour contracts and where there may be a number of different duty holders.
"Working alone is inherently more hazardous than working with the support of colleagues. Public sector workers often visit people in their homes, which brings a unique set of risks," said Unison acting head of health and safety Robert Baughan.
"Lone workers get less support from colleagues and it's more difficult for them to get help if something goes wrong. As the number of lone workers increases, employers must put safety above profit and put measures in place to protect workers."
The union warns that regulatory bodies and government have failed to keep pace with the growth in zero-hour contracts and home care workers that has resulted in an increasingly isolated and vulnerable workforce.
The guide encourages employers to minimise lone working where possible and explains the importance of good health and safety management to help reduce risks where workers have to work alone.
The document calls on employers to identify the times when workers may be most at risk, so help and support can be better targeted at those times. Procedures should be in place when workers fail to make contact or can't be contacted. Staff should also always know where colleagues are, along with their expected arrival and departure times.
Lone workers should be provided with names and details of colleagues they can contact outside normal working hours, the guide adds.