Data released by the authority shows that there has been a spike in reported break-ins at unused properties.
Hertfordshire County Council revealed it has seen footage of break-ins that have been shared online. It also says that a number of out-of-use properties that it owns have been targeted.
Councillor Chris Lucas said: "We've seen a 352% increase in the number of break ins in our owned properties, many of which are awaiting remedial works due to structural or hazardous issues. Sadly, despite clear signage and visible warnings, we are still seeing people enter our properties without permission. The signs are there for a reason. If you ignore signage and enter this kind of property you could be in danger of getting seriously injured or exposed to harmful substances."
The authority warns that its CCTVs are in use at empty properties and break-ins will be reported to the police. Hertfordshire County also cautions that asbestos may be contained within the walls, ceilings, insulation and pipework of the abandoned buildings.
It also says that floors, stairs, and roofs could collapse within the disused buildings. Potential trespassers are also warned about the possibility of encountering broken glass and/or sharp objects that could cause serious cuts and infections. Electrical hazards may also exist at the abandoned properties where wiring might be damaged and people could potentially receive electric shocks or accidentally spark fires.
The council also warns if a person becomes trapped or injured inside a property they may not be found quickly.