As the popularity of tattoos continues to grow, so does the concern about potential risks. Some risks, such as the spread of infections through the use of unsterilized needles, are known. But what is not clear is the safety of tattoo inks.
The US Food and Drug Administration (FDA) has received reports of bad reactions to tattoo inks right after tattooing or even years later. Some people report itchy or inflamed skin around their tattoos in the summer when they have been out in the sun. Recent reports associated with permanent makeup inks have prompted FDA to study tattoo ink safety.
–“Think Before You Ink: Are Tattoos Safe?”
US Food and Drug Administration

What is the main idea presented in the passage?
Tattoos can cause infections through dirty needles.
The safety of tattoo inks has not been studied enough.
Getting a tattoo is a very high-risk activity that is not recommended.
The FDA controls and licenses tattoo parlors.

The text begins with the statement that it is already known to all people that the needles used to make tattoos can spread infections. This subject has already been much discussed and talked about and is already known to the population.

However, the text wishes to talk about a little unknown danger related to tattoos, which is the safety of tattoo inks. The text says that there is not enough research to say whether these paints are safe or if they promote any risk to the organism.