"We investigated whether those with any involvement in taking tourists to the island were meeting their obligations under the Health and Safety at Work Act 2015," Parkes said.
"We consider that these 13 parties did not meet those obligations. It is now up to the judicial system to determine whether they did or not. WorkSafe can't comment on the matters in front of the court."
This tragedy had a wide-ranging impact on victims, families, communities and iwi, he said.
"There were 47 people on the island at the time of the eruption, all of whom suffered serious injuries and trauma, and 22 of those have lost their lives."
The charges were laid in Auckland District Court.
Ten organisations were charged under the Health and Safety at Work Act 2015.
Three individuals were charged under section 44 of the Act which requires directors, or individuals with significant influence over a company, to exercise due diligence that the company is meeting its health and safety obligations.