Prevent infants from swallowing resin balls which swell in water! (follow-up)

In about six months from June to December 2021, the Doctor Mailbox¹ on NCAC's website received three reports that an infant suffered from intestinal obstruction after accidentally swallowing a resin ball which swell in water (toy made of superabsorbent polymer) and underwent surgery. Then, NCAC issued an alert on this problem on December 23, 2021.

Even after that, the Medical Facilities Network² received a report of similar accident occurred in December 2021. In all of these cases, a child suffered from intestinal obstruction due to accidental swallowing of a superabsorbent polymer product. In 2015, NCAC reported similar cases related to interior ornament balls made of superabsorbent polymer. It has been reported that similar incidents happened overseas as well and some of the victims resulted in death.

These superabsorbent polymer products are still sold at physical and online stores in Japan. NCAC decided to test seven brands of superabsorbent polymer products sold in the market and to issue a consumer alert to prevent similar accidents.

1. ¹ NCAC has a webpage called "Doctor Mailbox" to catch information directly from doctors about accidental injuries caused by products or services, which will be used to help prevent similar incidents.
2. ² The Medical Facilities Network is a joint project by the Consumer Affairs Agency and NCAC which started operating from December 2010. The network collects accident reports on people.

Cases reported to the Medical Facilities Network

Superabsorbent polymer balls were stored in the bathroom. My child took the balls without my knowing and played with them. Two days later, my child started to vomit. Symptoms of vomiting and abdominal pains continued. My child was diagnosed with intestinal obstruction, but the cause was unknown. The child underwent abdominal surgery and something foreign was felt in the ileum by palpation. The foreign matter was pressed from outside of the intestine and moved to the colon. Three days later, the foreign matter was excreted.

Test results

Estimated size of the ball swollen in the body

The superabsorbent polymer balls swelled to a greater degree when soaked in artificial intestinal juice than when soaked in artificial gastric juice. In an extreme case, the diameter increased from 15 mm to nearly 40 mm.

Photo: Before and after being soaked in artificial intestinal juice
Example of a big ball (left side) and a small ball (right side)

Labeling and representation

Labeling about risk of intestinal obstruction due to accidental swallowing

None of the brands gave a specific precaution that abdominal surgery would be required in case of intestinal obstruction due to accidental swallowing of the product.

Other precautions for use

Four out of seven brands did not label precautions for use in Japanese on the product package.

Advice for consumers

• In case of accidental swallowing, a superabsorbent polymer substance swells in the digestive tract and may cause intestinal obstruction that may require abdominal surgery. Supervise children when they use superabsorbent polymer products, even if they are older than recommended ages. Store superabsorbent polymer products in a safe place out of the reach of children.
• Take a child immediately to a hospital for a medical examination if you discover or if you suspect that the child has accidentally swallowed a superabsorbent polymer substance.
• If there's any child younger than the recommended ages for superabsorbent polymer products in your home, consider refraining from buying such products.

Request to businesses

• Consider refraining from selling superabsorbent polymer products as toys and recalling products that have caused harm.
• Improve product design and other elements in order to prevent serious harm even if a small child has accidentally swallowed a superabsorbent polymer ball.
• Write precautions in large letters on each product package that accidental swallowing of the product may lead to serious harm such as suffocation and intestinal obstruction. If consumers read them before purchase, it helps prevent children from accidental swallowing and subsequent physical harm.

Request for cooperation to online shopping mall operators

• Keep consumers and sellers informed that superabsorbent polymer products may cause serious harm such as suffocation and intestinal obstruction in case of accidental swallowing.

Request to the government

• Consider the propriety of selling superabsorbent polymer products as toys. Injuries due to accidental swallowing should not be repeated.
• Remind consumers regularly and repeatedly of the risk of accidental swallowing of a superabsorbent polymer substance.