US healthcare giant Johnson & Johnson denied that its baby shampoo products contain cancer-causing chemicals on Thursday.

"The ingredients used in Johnson's Baby products, including preservatives that are designed to release tiny amounts of formaldehyde to protect against harmful bacteria growth, are safe and approved by regulators in every country or region in which they are used, including the US, EU, and China," the company said in a statement.

"While different formulations of similar products around the world may contain different ingredients, all conform to regulatory requirements..."

On Tuesday, the Campaign for Safe Cosmetics released a report saying that Johnson & Johnson still sells baby shampoo that contains chemicals harmful to babies in 13 countries including China, while the company sells such products in at least eight other countries without the harmful chemicals.

The organization has been urging Johnson & Johnson to remove two chemicals from its baby products since 2009.

One of the chemicals, quaternium-15, is a preservative that kills bacteria by releasing formaldehyde, which was declared a human carcinogen by the World Health Organization in 2005.

The other chemical, 1,4-dioxane, which is a byproduct of a process for making chemicals more soluble and gentler on the skin, is suspected of causing damage to the central nervous system, liver and kidneys.

But between July and October of 2011, the Campaign for Safe Cosmetics purchased and reviewed labels of Johnson's Baby Shampoo sold in 13 countries to see if the products contained quaternium-15, and found that the shampoo sold in the United States, Australia, Canada, China and Indonesia contains quaternium-15, while the shampoo sold in Denmark, Finland, Japan, the Netherlands, Norway, South Africa, Sweden and the UK contain non-formaldehyde preservatives.

"Johnson & Johnson clearly can make safer baby shampoo in all the markets around the world, but it's not doing it," Lisa Archer, director of the Campaign for Safe Cosmetics, told the Associated Press. "It's clearly a double standard, something they can easily fix."

In Shanghai, the company's baby shampoo products could still be seen on the shelves of supermarkets and personal care retailers on Thursday. However, a salesman in a Watsons store in Shanghai's Huangpu district said he sold only five bottles of the 400-milliliter baby shampoo on Wednesday, while normal daily sales for the product were about 10 bottles.

"Customers seem to be scared by the news," said the salesman who refused to be named.

Shan Ping, the mother of a 2-year-old daughter, said she will not buy any Johnson & Johnson products until the matter is clarified.

"You have to be careful when it comes to babies," she said.

Rene Crevel, a safety and environmental officer for Unilever, which produces personal care products, said a company should stick to a unified global standard for its products.

"This is not only a basic philosophy in production, but also shows the integrity of a global brand," he said.