The facts on 1,2,3-Trichloropropane

Estimates of current numbers of exposed workers to 1,2,3-Trichloropropane (1,2,3-TPC) in the EU are not available. Inhalation is considered as the primary route of exposure although workers can be exposed through dermal contact as well.

1,2,3-TPC is classified as Carcinogenic Category 1B (according to CLP Regulation), which means it is presumed to have carcinogenic potential for humans, based on animal evidence.

There is no human data on whether 1,2,3-TCP causes cancer in humans available. Studies in animals show that prolonged exposure to this substance may cause tumours at multiple sites, such as in the oral cavity and forestomach.

Where risks occur

The primary use of 1,2,3-TPC is as a monomer in the manufacture of polymers or as an intermediate in the production of other substances (pesticides, 2,3-dichloropropene, polysulfides and hexafluoropropylene). 1,2,3-TCP may remain as an impurity in some of these chemicals. 1,2,3-TCP is produced in significant quantities as a by-product during the manufacture of epichlorohydrin when chlorine is added to allyl chloride. This process takes place in closed systems.
In general, workplace exposure appears to be limited due to handling under strictly controlled conditions. The main activity where exposure is possible is during manual maintenance or cleaning activities.

More about the substance

In its pure form, 1,2,3-TPC is a colourless to yellow liquid with limited solubility in water, a strong chloroform-like odour, moderate volatility, and high flammability. It’s a man-made chemical, present in the environment as a result of anthropogenic activity.
An EU-wide binding occupational exposure limit value is currently under preparation.

Hazards that may occur

Acute toxicity data in humans are limited to a small number of case reports, which describe primarily liver and neurological effects following high, but generally not well‑quantified, oral or inhalation exposure. The most relevant health effect of chronic exposure to 1,2,3‑TCP is carcinogenicity. No data are available in humans. In experimental animals, 1,2,3‑TCP induces tumours at multiple sites and with high incidence in both mice and rats. As the metabolism of 1,2,3‑TCP is qualitatively similar in human and rodent microsomes, it is considered likely to be carcinogenic to humans.

What you can do

At the workplace, the most effective way to prevent exposure is by substitution of 1,2,3-TCP. Where substitution is not possible and use of 1,2,3-TCP cannot be avoided, measures to reduce exposure must be taken.

The most effective way to avoid exposure to 1,2,3-TCP is to develop and use closed systems. Where this is not possible, technical measures such as effective local exhaust ventilation, supplemented by good general workplace ventilation and regular checks of their effectiveness, should be implemented to ensure that exposure is minimised as much as technically possible.

Implement regular exposure assessments to check if your protective measures in place are effective or whether further actions need to be taken. Workers need to be aware of the effects of exposure and should be trained regularly on the control measures necessary for working safely with 1,2,3-TCP to prevent exposure. Involving an occupational physician is recommended.

Ensure that workers have adequate personal protective equipment, such as protective clothing and gloves, if necessary. Personal protective equipment should not be used as the only preventive measure. As many of the above technical and organisational measures as possible must have been implemented beforehand. Make sure the right personal protective equipment is used, like eyes and face protection, gloves, protective clothing and breathing protection. In addition, when selecting equipment, the anatomy of the workers who will be using it must be taken into account and, in the case of respiratory protective equipment based on facial adjustment, it is highly recommended that a fit test be carried out on each person. Additionally, all workers should be instructed to wash their hands properly before taking a break or entering another area, and to wash themselves and change their clothes at the end of each shift.

Personal protective equipment should only be used as a last resort and only considered temporarily, after the possible technical solutions have been exhausted.

References: ECHA