Conn. Gen. Stat. § 31-341: Notice to insurer.

When a claim for compensation by any such injured employee or the dependent of an injured employee of an employer who has insured his liability as aforesaid does not result in a voluntary agreement and a hearing before an administrative law judge is necessary to determine such claim, the insurer shall receive the same notice of such hearing as is by law required to be given to the employer and shall thereupon be a party to the proceeding.