WASHINGTON (CNN) - One of the most popular toys for children this summer, the Super Soaker Monster Rocket, is being recalled because a part of it can pop off and cause cuts and in one case, a concussion, said a government agency Thursday.

The recalled, 7' tall Monster Rocket

The recall of 230,000 of the toys -- made by Hasbro Inc., of Pawtucket, R.I. -- follows four reports of injuries caused by the cap on the rocket. The cap can come off unexpectedly when unscrewed from the tank and cause impact injuries, the Consumer Product Safety Commission said.

Hasbro has received four reports of the cap coming off, causing three injuries. One incident resulted in a concussion, and another required one person to receive stitches. If not properly launched the tail of the rocket can come off also causing injuries.

Hasbro also received four reports of children being struck by a descending rocket; those reports resulted in three cuts that also required stitches.

The Monster Rocket inflates into a 7-foot mylar rocket, which has a blue-and-orange launch base with a water tank attached to one leg. It is made of plastic with "fins" made of foam. It costs about $30.

Consumers are being urged to stop using the toy immediately and contact Hasbro for a replacement toy of equal value. Consumers can contact Hasbro by calling 866-487-4737 or logging on to www.supersoaker.com.