Premature babies are exposed to unsafe levels of a chemical found in the products used in their treatment, according to new research, which raises questions about whether the medical interventions used on preemies could be causing them harm.

The chemical is known as DEHP, or di(2-ethylhexyl)phthalate, and it helps make plastic products more flexible. DEHP is found in a variety of consumer products, and is approved for use in medical devices in both the United States and Canada.

The research, conducted by a team of scientists from the Johns Hopkins Bloomberg School of Public Health, has found that preemies may be exposed to DEHP levels between 4,000 and 160,000 times higher than levels considered safe.

"It's remarkable that the care of sick and developmentally vulnerable preterm infants depends on an environment composed almost entirely of plastic," lead study author Dr. Eric B. Mallow, a neonatologist and senior research program co-ordinator at the Bloomberg School, said in a statement.

"The role of these synthetic materials in the clinical course of our patients remains almost completely unexplored.”

The study is published in the online edition of the Journal of Perinatology.

Medical products that are made from PVC, or polyvinyl chloride, and used to treat infants include most types of intravenous tubes, catheters, endotracheal tubes, and bags that store blood and other fluids.

Many of these items are used on preterm infants during weeks and perhaps months of treatment at a hospital’s neonatal intensive care unit (NICU).

Because DEHP does not bind chemically to PVC, the researchers say, it is able to leach into fluids and body tissues with which it comes into contact.

For their study, the researchers analyzed the current scientific literature that looks at the potential health effects caused by phthalates such as DEHP, which are considered endocrine disruptors, meaning they interfere with normal hormone function.

However, the researchers found evidence that DEHP can cause a wide range of other toxic effects, which could impact both the short- and long-term health of preterm infants. Animal studies have linked DEHP to inflammation, liver injury and compromised development of the lungs, brain and eyes. Follow-up clinical studies have found evidence of liver injury in NICU patients, the researchers said.

Human studies on whether DEHP is linked to lung, brain or eye problems do not yet exist.

The use of DEHP and other phthalates in children’s products is strictly regulated in both the United States and Canada. In Canada, allowable concentrations of DEHP and other phthalates are restricted to no more than 1,000 mg/kg in the soft vinyl of children’s toys and child care items.

The use of DEHP in medical products is unregulated in the United States. There are no regulations in Canada that ban or limit the quantity of DEHP in medical devices, a Health Canada spokesperson said in a statement to

However, companies seeking to obtain a licence for a new medical device must declare whether it contains DEHP at a level greater than 0.1 per cent of the mass of the device.

The research released Thursday found that total daily exposure to DEHP for an infant weighing two kilograms can reach 16 mg/kg per day. The main sources of exposure include the receipt of blood products, as well as tubes placed in the airway to aid in breathing.

"We were floored by how high the exposures are when you look at all of the devices together," co-study author Mary A. Fox, an assistant professor in the Department of Health Policy and Management, said in the statement.

"It's a population that we know is vulnerable to begin with. They're struggling to survive. And the concern now is whether this phthalate exposure is actually contributing to their problems when these medical products are supposed to be helping them get better."

A first step for reducing DEHP exposure among preemies would be to replace devices that contain the chemical with alternative products. Products with DEHP used in hospital construction, such as flooring and paints, could also be swapped for phthalate-free products, the researchers say.

And visitors and staff could be prohibited from using products, including soaps and lotions, that contain phthalates.

"We do have to make tradeoffs and we want to save these babies," Fox said.

"But can we save them by using alternative products that reduce their exposures to substances that may be harming them? It seems like we could."