A research paper by the Harvard School of Public Health has strengthened the link between formaldehyde and amyotrophic lateral sclerosis (ALS). The disease, which is also known as Lou Gehrig's disease damages person’s nerves and he gradually becomes paralytic.

Study’s lead researcher Andrea Roberts said that people having jobs that require exposure to formaldehyde were around three times as likely to do of the ALS as people who were not exposed to it.

For the study, the researchers have used a database of almost 1.5 million people. They were followed from 1973 till the time of their death. The European Commission has taken steps to limit the use of formaldehyde, but did not ban it.

It is a progressive disease whose symptoms include muscle weakness, paralysis, respiratory failure and death. Currently, there is no known cure for the condition. The researchers have also stated that funeral directors use formaldehyde to embalm bodies and they could be at the greatest risk.

The disease affects around 30,000 Americans. Formaldehyde is to make wood products. It is also used to make permanent press fabrics and helps preserve tissue and is also used to store biological samples and in mortuaries.

Most of the ALS deaths were among people having no exposure to formaldehyde and two men were found to have a high probability of formaldehyde exposure at high levels.

The researchers said, “Jobs involving both high probability and high intensity of formaldehyde are relatively uncommon in the USA, and ALS is also rare; there were only two ALS deaths among men in such jobs”.