Safety officials reported an increase in the average number of drowning deaths in pools and spas among children under the age of five, heightening concerns among consumer advocates about cheap, inflatable pools that often don't have the added safety measures of fences or alarms.

According to a new report from the Consumer Product Safety Commission, the average annual number of drowning deaths involving children younger than five in pools and spas has increased from 267 for 2002-2004 to 283 for 2003-2005. The majority of deaths and injuries occur in residential settings and involve children ages one to two, according to the commission.

consumerreports.org Consumer advocates worry about the safety of inflatable pools.

"We have to make sure that parents and caregivers understand when you've got a child around a body of water, you can't take it lightly," says acting commission chairman Nancy Nord. "You have to be vigilant."

Safety officials say they aren't certain about the cause of the increase. Yet consumer advocates point out that large and relatively cheap inflatable pools that are now widely available at supermarkets and big-box stores are a growing concern. These pools, unlike in-ground models -- which usually require a construction permit -- are less likely to be subject to local safety codes that call for measures such as fencing, covers or alarms, advocates say. Inflatable pools can be quite large, accommodating several adults and, in many cases, accessible by a ladder.

Donald Mays, senior director of product safety and technical public policy at Consumers Union, a nonprofit consumer advocacy group, urges consumers not to buy such inflatable pools. He says that the sides are often pliable, making it easy for a child to topple in.

Mr. Mays also says that such pools' covers are usually designed to keep out debris but cannot withstand the weight of a person. He mentioned an incident in which kids playing on a cover of one of these pools got entangled and drowned.

"The fact is that when people buy these very inexpensive pools at drugstores or the supermarket, towns are not aware they are being installed ... and safety measures don't get put in," Mr. Mays says.

Carvin DiGiovanni, senior director, technical and standards, of the Association of Pool & Spa Professionals, an industry group based in Alexandria, Va., says that consumers need to make sure such products are installed to local codes. He says the manufacturers are putting educational information in their products urging them to do so.

Calls to individual manufacturers of above-ground pools, including Intex Recreation Corp. and General Foam Plastics Corp., weren't returned Wednesday.

Steven Getzoff, national outside counsel to the industry group, pointed out that given the increase in the number of pools in the U.S., the number of drowning deaths per pool has actually gone down. According to P.K. Data, a market research and consulting firm in Duluth, Ga., the number of residential in-ground and above-ground pools, hot tubs and commercial pools grew from roughly 12.5 million in 2002 to more than 15 million in 2007.

"Of course, this number isn't a number anybody is happy with," he says, referring to the increase in drownings.

The commission's latest figures on drowning deaths come after the recent passage of the Virginia Graeme Baker Pool and Spa Safety Act, which aims to promote general pool safety and prevent drowning deaths from entrapment in drains. It requires, for example, that by Dec. 19, 2008, all public pools and spas have safety drain covers and, in certain circumstances, an anti-entrapment system.

From 1999 to 2007, there were 74 reported incidents involving entrapment, resulting in nine deaths and 63 injuries, according to the report. All of the deaths except one involved children 14 or younger.

Safety officials point out that while getting caught in drains can pose a risk, drowning is more common when children get access to water without adult supervision. Drowning is a leading cause of unintentional death in children ages one to four, according to the commission.

One problem, say safety advocates, is a lack of national standards on many elements of pool safety, such as fences, alarms and covers. Codes vary around the country, and enforcement is often spotty. Mr. Mays says that while these extra layers of protection are important, the "No. 1 defense is parental supervision."

Stew Leonard Jr., owner of the supermarket chain that bears his name, is on a mission to educate children, as well as parents. In 1989, his two-year-old son drowned in a pool, with many adults around, while the family was vacationing.

Mr. Leonard now educates children on pool safety through his "Stewie the Duck" books and CD. All proceeds go to foundation he created in his son's name, the Stew Leonard III Water Safety Foundation, which funds safety education and swimming lessons for underprivileged youth.

"Adults always say, 'This would never happen to me,' " he says. "But somehow he just slipped into the pool unnoticed in front of a large group on a bright sunny afternoon. By the time we noticed, it was too late."

Write to Sara Schaefer Muñoz at sara.schaefer@wsj.com

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