Soldering Health Risks – How to Stay Compliant

One of the major health concerns in the electronics industry is exposure to fumes generated through soldering. Direct contact and inhalation of fumes released from Rosin (also referred to as Colophony) or its derivatives used in the flux cause a wide range of damaging health implications.

Fumes released during electronic soldering

The heated flux creates fumes that move directly towards the breathing zone. Image by

Business owners and managers alike must consider the impacts that the use of soldering can have. This guide is to give those with responsibility to control hazardous substances a greater insight into the dangers that soldering presents.

In this post you will learn;

  • What Rosin is
  • Why Rosin is used in Soldering
  • How exposure to Rosin can take place
  • What health risks are associated with Rosin fumes
  • What actions you must take to control and prevent the exposure to Rosin

What is Rosin?

Naturally occurring, Rosin is a solid, resinous material obtained from pine trees. Consisting of a mixture of approximately 90% resin acid (mostly abietic acid) with 10% neutral material such as stilbene derivatives and different forms of hydrocarbons.

Use of Rosin in Soldering

Rosin is used mainly as a flux in the electrical and electronics industries where it is heated with the solder (usually tin/lead) to make electrical connections.

Rosin used as a flux in the soldering process

Rosin used as a flux in the soldering process Image by

A flux aids the soldering process by cleaning the surfaces which are to be joined, increasing solder flow and most importantly, preventing oxidation which leads to weaker bonds in the joint. However when heated, airborne products are generated including aliphatic aldehydes such as formaldehyde.

Most fluxes are also composed of organic amine hydrochloride, an activator utilised to clean the soldering area. When heated, it releases hydrochloric acid and other gases containing benzene, toluene, styrene, phenol, chlorophenol and isopropyl alcohol.

How Exposure to Rosin Occurs

Without effective control, solder fume rises vertically and for manual operations this means that it is likely to enter the breathing zone of the solderer. Its not just those in direct vicinity that are in danger, fumes drift and move throughout buildings particularly in areas where solder work is intense and overall ventilation is low, putting other members of staff (and potentially the general public) in danger.

Health risks caused from Rosin fumes

Occupational Asthsma

Heating of the flux containing Rosin (or derivatives) during soldering produces fumes. These fumes are one of the leading causes of occupational asthma in the UK. Once asthma has developed, even small exposures to fume can lead to immediate or delayed asthma attacks. The fumes can also act as an irritant to the upper respiratory tract and eyes, and on contact with the skin these fluxes or their fume can cause dermatitis.

Other Health Risks Associated with Rosin and Solder Fume

Early symptoms from Rosin fume exposure can include;

  • Watering or prickly eyes
  • Running or blocked nose
  • Sore throat
  • Coughing, wheezing, tight chest and breathlessness

Information for Employers – Soldering Safety & Compliance

Any organisation that undertakes soldering activities is subject to the Control of Substances Hazardous to Health Regulations (2002).

The following Maximum Exposure Limits (MEL’s) have been set by the Health & Safety Executive (HSE) for rosin-based solder flux fumes:

0.05 mg m-3 (over an eight-hour reference period)
0.15 mg m-3 (over a fifteen-minute reference period).

The steps below outline a suitable structure that businesses can follow to achieve the maximum levels of safety and compliance within the workplace.

1. Assess the Dangers

Under COSHH you must assess the risks to health arising from the use of hazardous substances at work and apply the 8 good principles outlined below;

  • Assess the risks from substances hazardous to health
  • Decide what precautions are needed
  • Prevent or adequately control exposure
  • Ensure that control measures are used and maintained
  • Assess the risks from substances hazardous to health
  • Carry out health surveillance if appropriate
  • Put in place procedures for emergencies and spillage
  • Provide supervision, information, instruction and training to all employees

2. Prevention & Control

Ensure that, wherever practicable, exposure to hazardous fumes are prevented, or if not practicable, are adequately controlled, ideally via total or partial enclosure of the fume generating process.

If adequate control cannot be achieved, decide what alternative control measures are needed, this could be local exhaust ventilation or personal protective equipment. Maintain all control measures and ensure they are used.

Solder Extraction Solutions

We provide ‘On Tip’ (top) and ‘Stay Put Arm’ solder extraction solutions

Our range of ‘on-tip’ or ‘stay put arm’ solder fume extraction solutions provide workplaces with adequate levels of control. In each instance, hazardous fumes are pulled away from the breathing zone and safely extracted to be returned as clean air.

3. Ongoing Maintenance & Testing

Monitor occupational exposure levels and compare with published standards, such as HSE Guidance Note EH 40: “Workplace Exposure Limits” Provide health surveillance, as required

Provide necessary information, instruction and training and schedule a review of all COSHH assessments at least every two years or whenever there has been a change in the workplace or the process.

Achieve Solder Fume Compliance with BenchVent

With over 20 years experience in the manufacture, distribution and installation of solder fume removal systems, we are one of the leading suppliers in the UK. Each product is built here in the UK in our North Yorkshire production centre and benefits from our unrivalled lifetime guarantee.

For more information, please telephone our support team today on 01423 790 039. Alternatively, if you would like to contact us online, simply fill out our contact form. Response time is typically 24-48 hours.

Related Reading

Soldering Guide for Education Providers – Solder Fume Extraction in Schools
BenchVent Electronic Fume Extraction – Fume Extraction for the Electronics Industry

All information is deemed accurate at point of publishing and is subject to change.

Download the full HSE Controlling health risks from rosin (colophony)-based solder flux fume via the link below.