Chronic exposure to high concentrations of 1-bromopropane (1-BP) vapor is highly toxic to nerves, according to data presented here Tuesday during the annual meeting of the American Neurological Association.

1-BP is an industrial solvent widely used in the US and Japan and introduced to replace ozone-depleting chemicals. Dr. Jennifer J. Majersik of the University of Utah described six individuals who worked in a factory gluing foam cushions together who were exposed to 1-BP vapors from spray adhesives over several months.

All six developed severe symptoms of nerve damage, including leg or foot pain and muscle weakness and spasms.

Five had difficulty walking and two of the most severely affected individuals regained only minimal function 15 months after exposure and still require assistance walking. Three others continue to complain of chronic nerve pain.

Air samples taken at the factory one day after use of the solvent was halted showed 1-BP air concentration of 130 parts per million (ppm), well above the safety level of 25 ppm currently set by the Environmental Protection Agency.

Poor ventilation in the factory led to the high 1-BP levels. “It was winter, the heater in the factory was broken so the employees turned off the fan because it was cold,” Majersik explained.

“1-BP is highly volatile so it is easily breathed in and it is probably also absorbed in the skin so it requires a lot of ventilation,” she said.

There have been a few “red flags” regarding the neurotoxic effects of 1-BP, Majersik said.

Just recently, several factory workers in North Carolina who were also using 1-BP-containing glue to assemble foam cushions reported neurological symptoms after exposure. Factory workers in China have reported numbness in their toes and mental deficits following 1-BP exposure.