Determining if a product contains the plastic-softening agent DEHP can be difficult.

Information about ingredients typically is a trade secret that many plastics manufacturers may be reluctant to discuss, according to both the Chemical Manufacturers Association and the Society of Plastics Industries -- two trade groups representing the majority of companies making plastic products.

One rule of thumb recommended by chemists is that hard plastics -- the kind with little flexibility -- usually have not been treated with softening agents like DEHP. Neither are most items that come into contact with food, including plastic wraps and bags, which usually are made of polyethylene -- not the polyvinyl chloride which needs a plasticizer to make it softer.

A spokesman for the Toy Manufacturers Association of America, an industry group that also represents the makers of infant pacifiers, said "most manufacturers have already discontinued use of DEHP in their products and the rest have voluntarily agreed to do so immediately" based on the new CPSC report.

Even the DEHP-containing pacifiers that made headlines last week don't contain the chemical in the nipple itself, but rather have it in the outer rim surrounding the nipple, in the handle or in the pacifier guard. Moreover, those pacifiers are only one of three types available. The others, made of silicon or latex, do not contain DEHP. Information about the contents appears on most pacifier labels.

While the vinyl coverings for baby mattresses, crib bumpers and baby vinyl pants also have been targeted by the Consumer Product Safety Commission as potential DEHP-containing items, the outer plastic covering of disposable baby diapers does not contain the chemical, report spokesmen for Procter & Gamble (makers of Pampers and Luvs) and Kimberly-Clarke (manufacturer of Huggies).

When in doubt about a product, the best bet, advise the trade associations, is to check with the manufacturer. Consumer questions about the content of plastics products can be directed either to the Consumer Product Safety Commission's toll-free hotline (1-800-638-CPSC), which will provide manufacturers' phone numbers and addresses, or directly to the manufacturer of a product in question.