WASHINGTON (MarketWatch) -- Almost half of vinyl toys in recent testing contained an additive that has been linked to harming reproductive development, according to a new study from a Washington state-based public health group.

Dolls, squeeze toys, animal figurines, and other products for kids were found to contain phthalates, an additive used to make brittle vinyl toys more pliable.

"Kids can be exposed when they suck on the toy or chew on the toy. They can also absorb phthalates through the skin," said Erika Schreder, a staff scientist at the Washington Toxics Coalition, which produced the "Not So Squeaky Clean" report. "Because phthalates are not chemically bound to the plastic, they get out in the environment, and so another exposure is that children are exposed to [phthalates in] house dust."

Phthalates have been banned from most toys in the European Union because of health concerns, and the Washington Toxics Coalition is urging regulation in the U.S. on the state level. The coalition also said that labeling should reveal whether phthalates are present.

Last year, California passed a law banning phthalates in children's products, effective January 2009. Jack Gerard, president and chief executive of the American Chemistry Council said the law "is the product of the politics of fear" and not based on good science.

Several studies have "explored possible associations" between phthalates and semen quality, shortened pregnancy terms, genital development in young boys and premature breast development in young girls, according to the Centers for Disease Control and Prevention, which said that more research is needed.

The CDC also reported that phthalates, which are found in a wide variety of consumer products ranging from raincoats to shampoo to intravenous medical tubing, are generally metabolized and excreted quickly, and do not accumulate in the body.

Some toymakers find alternatives

In laboratory testing, phthalates were detected in nine of 20 toys. The toys were purchased in Washington state and Michigan, at major retailers such as Target Corp. TGT, +0.30% and ToysRus Inc.

"We can expect that on a national level you would find about the same proportion," Schreder said. "There really wasn't anything special about the toys we bought here. None of the toys were locally produced."

In six of the toys tested, phthalates comprised 28% to 47% of the toy, according to the report. For example, more than one-third of a rubber ducky was made of phthalates, while almost half of a green ball was made of phthalates.

"What is really most unnerving is the fact that phthalates make up such a high proportion of these toys," Schreder said. "Can you think of it as an additive when it makes up so much of the toy?"

Of five Mattel Inc. MAT, +0.87% toys tested, none tested positive for phthalates, according to the report.

"While this is no guarantee that all Mattel products are free of phthalates, it does indicate that at least for these popular products, a major manufacturer has found an alternative ... that will allow the sale of its products in Europe as well as the U.S.," according to the report.

For its part, Mattel says it has voluntarily applied the European Union restriction "on a worldwide basis," according to a company statement. "Mattel has taken steps to eliminate the restricted phthalates from toys on a worldwide basis. In short, all Mattel toys manufactured and shipped from any manufacturing facility around the world [are] in compliance with this EU Directive."

The Washington Toxics Coalition report added that Target aims to eliminate phthalates from its own brand of toys this year, and that its bibs are already free of the vinyl that contains phthalates.