Efforts by the U.S. government to improve the safety of children's products is having unintended consequences by forcing extensive, and expensive, testing on a wide list of products.

Among them — hands-on science kits — that may face an uncertain future during the debate.

This generic science kit comes from a member of the HandsOn Science Partnership, a coalition of companies dedicated to increasing the access students and teachers have to hands-on science equipment. (HandsOn Science Partnership/Associated Press)The U.S. Consumer Product Safety Commission has been mired for weeks in deliberation as it writes guidelines on what makes a product a "children's product." That guidance is supposed to help sort out which products have to be tested under legislation passed by Congress more than two years ago that requires rigorous safety checks for lead, chemicals, flammability and other potential dangers.

Plenty of companies, from makers of handmade toys and Halloween costumes to firms selling science kits, have flooded the commission with requests for exemptions on some of their products.

For the makers of science kits, it is an issue that they say could lead to fewer hands-on science experiments for younger children.

The industry has asked the commission for a testing exemption for "general use" items such as rulers, rubber bands and paper clips inside the kits. They say the products aren't harmful to children, would be too expensive to test and shouldn't have to be tested because they are everyday items found in homes and schools that don't have to be tested if bought separately at retail.

Testing could lead to fewer products for kids under 12

A requirement to test, the kit makers say, would force them to refocus and market kits to older children instead of the 12-and-under crowd the law targets, leaving elementary school kids without those hands-on tools.

"If the first introduction a student has is seventh or eighth grade, you've lost them already," said Steve Alexander, business manager for the Hands On Science Partnership, based in Denver. The costs associated with "the testing requirements would far exceed the value of the materials in the kits," he said.

The partnership is a coalition of companies that sell hands-on science educational materials.

'The reason for this law is to ensure that products for children are safe.'— Rachel Weintraub, Consumer Federation of America

Consumer advocates say they are sympathetic to the costs associated with the safety testing but insist the tests must be done.

"The reason for this law is to ensure that products for children are safe," said Rachel Weintraub, director of product safety and senior counsel at the Consumer Federation of America.

The issue before the commission — coming up with a clearer definition of a children's product — has caused weeks of discussion, late-night meetings and some angst at the agency, which is charged with making sure thousands of products on the market are safe. A vote on the issue has been bumped three times already.

While it's clear an Elmo telephone toy for a toddler falls under the law and requires additional testing, there are products that linger in a grey area — such as the science kits or lamps and rugs that are decorated with fairies or trains. Those same rugs minus the fairies or trains would not have to undergo the additional, often costly testing.

The Halloween costume industry is concerned that strict consumer laws in the U.S. will require additional testing of costumes. (iStock)The Halloween industry, for example, says a superhero costume can be worn by teenagers and adults, so it shouldn't necessarily be classified as a children's product. Makers of handmade toys argued to the commission that child-sized musical instruments are similar to adult-sized instruments.

The Consumer Product Safety Improvement Act of 2008 defines a children's product as an item designed or intended primarily for children 12 years of age or younger.

Since passage of the act, critics have decried confusion in the marketplace about what products have to be tested, and how often.

The most frequent complaint concerns the law's unintended consequences, such as questions about whether library books for children need to be tested for lead.

The Consumer Product Safety Commission has since issued what amounts to an exemption for most ordinary children's books printed after 1985. For books printed before then, there's a concern about the level of lead in the ink used, but the agency does not require libraries to test and certify those books.