The Dagens Nyheter (DN) newspaper asked experts with the Karolinska Institutet hospital in Huddinge to test four different musical toys offered by the fast food giant.
The tests showed a continuous noise level higher than 115 decibels, well over the limit for children recommended by Sweden's National Board of Health and Welfare (Socialstyrelsen).
“This is totally inappropriate for children and totally incomprehensible,” said Dr. Björn Hagerman from Karolinska's laboratory for hearing technology, to DN.
The toys have been available in Happy Meals sold in Sweden since September 5th and come in six different varieties.
The toys tested resemble mobile telephones and can be pushed against the ear, writes DN.
But according to Claes Eliasson of McDonald's Sweden, the toys aren't meant to be used like mobile phones, but rather are supposed to be attached to a belt.
The company has tested the toys at a distance of 25 centimetres from the head and measured a noise level of 79 decibels.