ICOS are completely safe if you do research before investing as long as you are smart about it i.e.
For research: look into the whitepaper, you ask the ICO you are interested in, look at the team and what they are trying to achieve etc. If you throw money into a poor project, don't be surprised if you don't make any profit or they go under.
Don't throw too much money - Spend within your limits. Slowly build up your portfolio.
This does not guarantee success. Risks for investors may be related to the nature of the project, even if it is not a scam. In most projects, there is no reason to use blocking and crypto currency, so many do not go from the idea stage to the implementation, or the implementation fails. Projects that still submit the planned product often begin to accept the currency, reducing the value of their token.