This story was produced in collaboration with Consumer Reports.

Starting in 2007, Dr. Daniel Budnitz, a scientist at the Centers for Disease Control and Prevention’s Medication Safety Program, began tracking an obscure but unsettling statistic about children’s health.

Each year, more and more kids were being rushed to emergency rooms after swallowing potentially toxic doses of medication. By 2011, federal estimates put the figure at about 74,000, eclipsing the number of kids under 6 sent to ERs from car crashes.

In most cases, children experienced no lasting harm from accidentally ingesting pills or liquids from the family medicine cabinet, but about 1 in 5 had to be hospitalized for further evaluation. About 20 children died each year from such accidents, CDC data showed.

As an epidemiologist and the father of two kids, including one who had a penchant for putting things in his mouth, Budnitz became fixated on reducing drug overdoses.

In particular, he saw an easy solution for the roughly 10,000 emergency room visits a year involving liquids, such as over-the-counter pain relievers and prescription cough syrups.

It was a type of safety valve called a flow restrictor. The small plastic device fits into the neck of a medicine bottle and slows the release of fluid, providing a backup if caregivers leave child-resistant caps unfastened or kids pry them off.

In 2008, Budnitz persuaded drug makers, federal regulators and poison experts to come together on an initiative to add flow restrictors, which cost pennies apiece, to medicine bottles.

Today, however, that promise to make medicine safer for kids remains largely unfulfilled, hindered by industry cost concerns and inaction by federal regulators, an examination by ProPublica found.

Honoring a pledge made in 2011, drug makers have added restrictors to infants’ and children’s acetaminophen, the active ingredient in Tylenol. That year, roughly one-quarter of kids’ ER visits for drug accidents involved pediatric or adult formulations of acetaminophen.

But the industry has neither promised nor delivered such protection on other medicines, which account for more than half of kids’ ER visits stemming from drug accidents, including antihistamines, ibuprofen, and cough and cold preparations. ProPublica purchased more than 50 pediatric versions of these products marketed by nine different brands at outlets in California, New York and Washington, D.C., this month. None of the products we bought had flow restrictors.

In some instances, companies that have placed flow restrictors on acetaminophen-only kids’ products have not put them on bottles of pediatric cough and cold syrup that contain the same amount of acetaminophen.

"If flow restrictors work, they should be placed on all liquid products," said Dr. G. Randall Bond, a pediatrician and poison expert who has consulted with drug makers. “We need a technological change to get us to the next level of safety.”

Industry officials said that they were waiting for better data to quantify the extent to which restrictors mitigate kids’ risk from drug accidents before deciding whether to add the devices to more medicines.

“We will continue to evaluate whether other initiatives or interventions make sense,” said Barbara Kochanowski, the vice president of regulatory and scientific affairs at the Consumer Healthcare Products Association, an industry trade group for over-the-counter drug companies.

Industry leader McNeil Consumer Healthcare, the Johnson & Johnson unit that makes Tylenol, said it was committed to child safety, but said flow restrictors were only one part of the solution.

“We believe the first line of defense against accidental unsupervised ingestion is secure storage and immediately returning medicines to a high and out-of-sight location following each and every time the product is used,” the company said in a statement.

Makers of liquid acetaminophen started to add flow restrictors in 2011 and, in the absence of any government or industry standards, companies rolled out a variety of designs.

To gauge their effectiveness, Consumer Reports – an independent, nonprofit testing organization – tested the devices found on 31 different products, duplicating the ways a child was most likely to squeeze, shake or suck medicine from the bottle. The results, which were shared with ProPublica, confirmed that all models of flow restrictor reduced the amount of liquid that escaped under these conditions – an outcome Consumer Reports lauded.

This is critical with acetaminophen. While generally safe if taken as recommended, the drug can cause liver damage and death if taken in larger amounts. As ProPublica has reported, about 150 Americans die each year after accidentally overdosing on acetaminophen, and tens of thousands more are hospitalized, the vast majority of them adults.