Nearly 20 percent of the 84,000 chemicals in commercial use today in the U.S. are kept secret from both the public and even from governmental regulators, according to a recent investigation by The Washington Post.

Their names and physical properties are guarded from consumers and almost all public officials under a little-known federal provision found in the Toxic Substances Control Act, which requires manufacturers to notify the federal government of new chemicals that they intend to market, but allows manufacturers to exempt from public disclosure any information that the company feels could affect their bottom line.

According to the Government Accountability Office, 95 percent of the notices that manufacturers send for new chemicals request some sort of secrecy. Each year, about 700 new chemicals are introduced into the marketplace.

When the policy was designed a few decades ago, the idea was to protect trade secrets in a highly competitive industry — the chemical industry.

But now, amidst increasing public demand for more information about chemical exposure coupled with the Obama administration’s campaign promise to shine light on unnecessary governmental secrecy, that law may soon change.

Chemical lobbyists and manufacturers argue that secrecy is necessary to stay competitive.

"Even acknowledging what chemical is used or what is made at what facility could convey important information to competitors, and they can start to put the pieces together," said Mike Walls, vice president of the American Chemistry Council.

Government officials, scientists and environmental groups disagree, arguing that manufacturers have exploited weaknesses in the law in order to keep chemicals, and their environmental, health and safety information, a secret.

"You have thousands of chemicals that potentially present risks to health and the environment," said Richard Wiles, senior vice president of the advocacy organization Environmental Working Group, which documented the extent of the secret chemicals. "It's impossible to run an effective regulatory program when so many of these chemicals are secret."

Though many of the chemicals kept secret may be harmless, manufacturers have reported in mandatory notices to the government that many pose a "substantial risk" to public health or the environment. Of the secret chemicals, 151 are made in quantities of more than 1 million tons a year and 10 are used specifically in children's products, according to the EPA.

Currently, the EPA must prove that releasing information about a chemical won't hurt the manufacturer's bottom line, but the White House and environmental groups want Congress to put the burden of proof on manufacturers by asking them to prove why a substance should be kept confidential in the first place. In addition, they want federal officials to be able to share confidential information with state regulators and health officials in order to better facilitate information about chemical concerns.

In a sign of possible things to come, Steve Owens, the newly appointed assistant administrator for the EPA's Office of Prevention, Pesticides and Toxic Substances, last July ended confidentiality protection for 530 chemicals.

"People who were submitting information to the EPA saw that you can claim that virtually anything is confidential and get away with it," explained Owens.