Vaseline is pretty safe but it can be bad because of the contaminates that it contains. .
Unrefined petroleum jelly does contain some potentially dangerous contaminants.
The EWG suggest that a group of carcinogens called polycyclic aromatic hydrocarbons could cause cancer and damage the reproductive organs.
People interested in trying petroleum jelly should buy it from a reputable source.
Vaseline does not go bad.
In fact Vaseline can last a lifetime and possibly longer.
However when Vaseline is opened and exposed to the air then it may become less effective and get hard somewhat but it's not bad to use the Vaseline.
Vaseline is just petroleum jelly and other petroleum jelly brands are the same petroleum jelly but just with a different brand name.
When sealed the Vaseline or Petroleum Jelly is basically good forever.
In general, expired Vaseline is not dangerous.
Petroleum jelly has no pharmacological properties.
In other words, it has no chemicals, drugs, or compounds that would make it hazardous if expired.
If your Vaseline jar has gone past its expiration date but looks and smells fine, it should be safe to use.
Vaseline can sit on the shelf for years without significantly changing in form.
As long as it is kept at or below room temperature, it should be just as effective (its main use is to act as a “moisture barrier” - to hold moisture in the skin) 5 - 10 years after buying it.
Ultimately, the only main difference between Vaseline and petroleum jelly is that Vaseline is made up of pure petroleum jelly which contain minerals and microcrystalline wax so it is smoother, while petroleum jelly is made up of a partial solid mix of hydrocarbons that comes from mines.