Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Good for the Ozone -- Neurotoxic for Workers


A chemical solvent introduced to replace traditional ozone-depleting solvents in industrial settings has proven highly neurotoxic, according to a study presented October 5, 2004, at the 129th annual meeting of the American Neurological Association in Toronto.

Five workers whose job involved gluing foam cushions together with a glue containing the solvent 1-bromopropane (1-BP, also known as n-propyl bromide) developed severe neurological symptoms, some of which appear to be permanent.

"Two of the workers became profoundly weak, such that even now, eighteen months later, they cannot walk by themselves," said lead author Jennifer J. Majersik, MD, of the University of Utah. "Several others still have severe pain in their feet and legs, and several have lingering headaches."

1-BP is an organic solvent used to clean metals and electronics and as a solvent in adhesives. Although it has been used for many years in Asia, 1-BP only became a popular industrial solvent in the United States when it was tabbed to replace banned chlorofluorocarbon solvents that deplete the ozone layer of the atmosphere.

All six workers that Majersik and her colleagues examined had high blood levels of bromide, which indicates high exposure to 1-BP. The air concentration of 1-BP in the workplace was measured at approximately 130 parts per million (ppm) one day after use of the solvent was halted.

The Environmental Protection Agency (EPA) recommends a maximum 1-BP air concentration of 25 ppm. However, this figure is only a recommendation, and there has been no testing to discover whether even this concentration of 1-BP is safe in humans. What little is know about the health effects of 1-BP comes mainly from animal studies. "When rats are exposed to high levels of 1-BP, they suffer peripheral nerve and spinal cord damage resulting in profound leg weakness, just like our patients," said Majersik.

There have been a few warnings about the neurotoxic effects of 1-BP in humans. Workers who make 1-BP in China have recently been shown to have numbness of their toes and cognitive deficits with only minimal exposures. In addition, several workers in North Carolina, also gluing cushions together, were found to have neurological symptoms following 1-BP exposure.

There is no requirement that most chemicals be evaluated for health effects before they are introduced into industrial settings. Interestingly, 1-BP is an exception: Because it was designed to replace ozone-depleting substances, the EPA has undertaken a process to test the chemical. "But companies can still use the product while the testing is taking place, which can take years," said toxicologist Martin Caravati, MD, MPH, also of the University of Utah and another author of the report. "Even though there are workplace standards for protective clothing and ventilation, we know that they are not always followed, and workers get exposed to high doses of chemicals with unknown health effects."

The authors see a number of implications from their findings. "Physicians seeing patients who work in the manufacturing industry should take a careful occupational history of patients who come in with leg weakness or numbness. A high serum chloride is a tip-off to look for elevated serum bromide," said Majersik.

In terms of wider significance, the authors recommend greater involvement of national safety organizations such as the Occupational Safety and Health Administration (OSHA) to protect workers by mandating specific workplace requirements such as ventilation fans and respiratory masks. "It does appears from our work and that of others that appropriate air circulation protects workers from the toxic effects of the solvent," said Majersik.

316. Chronic Exposure to 1-Bromopropane Associated with Spastic Paraparesis and Distal Neuropathy: A Report of Six Foam Cushion Gluers, Jennifer J. Majersik, John D. Steffens, and E. Martin Caravati; Salt Lake City, UT

1-Bromopropane (1-BP) is being substituted for traditional ozone-depleting solvents in the industrial setting. We describe six cases of 1-BP neurotoxicity in foam cushion gluers exposed to 1-BP vapors from spray adhesives over several months. All patients complained of subacute onset of lower extremity pain or paresthesias and 5 of 6 complained of difficulty walking. On exam, five patients had bilateral lower extremity spastic paraparesis, distal sensory loss, and hyperreflexia. Serum bromide concentrations ranged from 44 to 170 mg/dL (reference 0-40 mg/dL). Factitious hyperchloremia was present with serum chloride concentrations of 105 to 139 mmol/L (reference 98-107 mmol/L). Air samples taken at the workplace one day after gluing operations ceased revealed a 1-BP mean air concentration of 130 ppm (range 91-176 ppm), well above the EPA-recommended 25 ppm. Fifteen months later, the two most severely affected patients had only regained minimal function and still required assistance to walk; three patients continued to experience chronic neuropathic pain. Chronic exposure to high vapor concentrations of 1-BP in the workplace was associated with a distinct and incapacitating neurotoxic syndrome.

| newswise
Further information:

More articles from Health and Medicine:

nachricht Advanced analysis of brain structure shape may track progression to Alzheimer's disease
26.10.2016 | Massachusetts General Hospital

nachricht Indian roadside refuse fires produce toxic rainbow
26.10.2016 | Duke University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel light sources made of 2D materials

Physicists from the University of Würzburg have designed a light source that emits photon pairs. Two-photon sources are particularly well suited for tap-proof data encryption. The experiment's key ingredients: a semiconductor crystal and some sticky tape.

So-called monolayers are at the heart of the research activities. These "super materials" (as the prestigious science magazine "Nature" puts it) have been...

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Steering a fusion plasma toward stability

28.10.2016 | Power and Electrical Engineering

Bioluminescent sensor causes brain cells to glow in the dark

28.10.2016 | Life Sciences

Activation of 2 genes linked to development of atherosclerosis

28.10.2016 | Life Sciences

More VideoLinks >>>