indg248 - solder fume and you

INTRODUCTION

●

This leaflet tells you about possible health hazards
from solder fume when using flux materials
containing rosin, sometimes known as colophony. It
also explains what your employer has to do and the
precautions you should take.

●

It deals only with the risks arising from exposure to
rosin-based or modified rosin-based solder fluxes.

WHAT IS ROSIN?

●

Rosin is a naturally occurring, solid, resinous material
obtained from pine trees. It is mainly a mixture of
resin acids, but up to 10% may consist of other acids
and neutral compounds.

●

Rosin is insoluble in water, but soluble in many
organic solvents. It may be obtained as gum rosin;
wood rosin; or tall-oil. Gum or wood rosin and
modified rosins are used for solder flux.

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. It may also be used for soldering in
plumbing and other pipe-fitting work.

●

A flux helps the soldering process by:

• cleaning the surfaces to be joined;

• increasing the flow of solder to make a good

connection; and

• preventing oxidation which might affect the

strength and quality of the joint.

●

Other special activators and modifiers may be
added to the flux to aid the soldering process. These
can present additional health hazards.

WHAT ARE THE HEALTH HAZARDS?

Respiratory effects

●

When heated, particularly to temperatures above
200°C, rosin-based solder fluxes form fumes
containing a range of resin acid particulates and
other components as gases. Lower temperatures can
significantly reduce the amount of fume produced.
Between 250°C and 400°C particulate fume levels
can triple.

●

When inhaled, rosin-based solder flux fume can lead
to occupational asthma or make existing asthmatic
conditions worse. The fume can also cause irritation
to the eyes and upper respiratory tract.

●

Rosin-based solder flux fume is now regarded as one
of the most important causes of occupational
asthma in Britain. When the asthmatic effects are fully
developed they are permanent and irreversible.
Continued exposure, even to very small amounts of
fume, may cause asthma attacks and the person
affected may be unable to do any soldering with
rosin-based fluxes again.

●

Typical early symptoms are watery and prickly eyes,
runny or blocked nose, a sore throat, coughing,
wheezing or breathing difficulties. These may start
within minutes of exposure or be delayed for several
hours, so that their link to work may not be
immediately recognised. However, improvement at
weekends and holidays often points to the symptoms
being job related.

●

The precise constituents of the fume causing
occupational asthma and irritation are not known.
From a review of scientific evidence it has not been
possible to identify a safe level of exposure below
which occupational asthma will not occur. Exposure to
all rosin-based solder flux fumes should, therefore, be
avoided or kept as low as is reasonably practicable.

Skin effects

●

On contact with the skin, rosin-based solder flux and
its fume can cause dermatitis. Both skin irritants and
sensitisers are present in solder fluxes and their fume.

●

Reactions have occurred from contact with liquid
fluxes, flux residues and, to a lesser extent, the fume
itself. Hands and forearms are mainly affected,
possibly from contaminated workbenches or other
surfaces. The fume may also affect the face and
neck.

●

Suitable precautions to avoid skin contact should
therefore be taken.

HOW EXPOSURE OCCURS

●

Without effective control, solder fume rises vertically
and for manual operations is likely to enter the
breathing zone of the solderer.

●

Fume may drift and accumulate in the workroom,
especially if the soldering work is widespread and
intense, and general background ventilation is poor.
Other people in the area who are not soldering can
therefore be put at risk.

●

People maintaining and cleaning soldering plant,
equipment and control systems may also be at risk.

●

Rosin-based fluxes may be integral with the solder or
applied separately as in liquid fluxes. For solder wire,
commonly used in hand soldering, the flux is often
contained in a central core and is released on
heating. In other cases, the flux may be within a
solder paste applied by syringe, or by stencil and
screen printing. Liquid fluxes may be applied from a
bottle or by dipping into small jars or pots. On
automated lines the flux may be sprayed as a liquid
or foam before wave soldering.

●

A large number of people including
telecommunications engineers, ventilation and
heating specialists, plumbers and those in technical
research and further education do some soldering.
Their intermittent soldering work may lead to high,
short-term exposures, particularly if carried out in an
enclosed space or at an awkward angle.

LEGAL REQUIREMENTS

●

As exposure to rosin-based solder flux fumes may be
hazardous to health, their use is subject to the Control
of Substances Hazardous to Health Regulations
(COSHH). A suitable assessment of the risks to health
must be carried out. Where reasonably practicable,
exposure should be prevented, or failing that,
adequately controlled (see overleaf).

●

The following Maximum Exposure Limits (MELs) have
been set for rosin-based solder flux fumes:

• 0.05 mg m

-3

(over an eight-hour reference

period); and

• 0.15 mg m

-3

(over a fifteen-minute reference

period).

●

Personal exposures to rosin-based solder flux fumes
are assessed by a sampling method which measures
resin acids and is described in MDHS83

Resin acids in

rosin (colophony) solder flux fume

HSE Books

ISBN 0 7176 1363 1.

●

To achieve adequate control, as required by the
COSHH Regulations, exposures to rosin-based solder
flux fumes should be reduced to as far below the MEL
as is reasonably practicable, for example by the
provision and use of a suitable local extraction
ventilation system.

●

If personal protective equipment is necessary, it must be
suitable and adequate for the purpose, meeting all
relevant requirements of the Personal Protective
Equipment at Work Regulations. It should only be used
as a last resort when other controls are not feasible or
adequate control is not achieved by other means.

●

Adequate information on the hazards and proper
precautions must be provided by the manufacturer
or supplier of rosin-based solder fluxes for use at
work. This is required by Section 6 of the Health and
Safety at Work etc Act 1974 or the Chemicals (Hazard
Information and Packaging for Supply) Regulations
(CHIP), as amended.

●

If employees are, or are liable to be, exposed to
significant levels of rosin-based solder flux fumes, the
COSHH Regulations require those employees to have
suitable health checks (health surveillance).

●

Medically confirmed cases of occupational asthma
or dermatitis must be reported to HSE or another
enforcing authority under the Reporting of Injuries,
Diseases and Dangerous Occurrences Regulations
1995 (RIDDOR).

WHAT SHOULD EMPLOYERS DO?

●

Properly manage the risks to health and the
precautions needed. Through suitable risk
assessment employers must in particular:

• check the workplace to find out if there is a

problem; and

• decide what to do to prevent harm.

If appropriate they must then:

• take action to control the risk; and

• check that what has been done is effective.

The assessment and precautions should be reviewed
from time to time or if conditions change, and
revised as necessary.

●

Find out how much exposure to fume occurs,
normally by means of a suitable monitoring
programme.

●

Ensure the proper use of any control measures
provided such as local extraction ventilation.

●

Properly maintain all control measures provided
(including extraction ventilation systems and
personal protective equipment) in efficient working
order and monitor their effectiveness. In particular,
extraction ventilation systems must be examined and
tested at least every 14 months and should be
regularly inspected by a responsible person on site
for defects. Appropriate records should be kept.

●

Where necessary, provide personal protective
equipment which is suitable for use and appropriate
to the job, but only as a last resort when prevention of
exposure or adequate control by other means are
not reasonably practicable. The reasons for such
protective equipment, the jobs for which it is
necessary and how it should be worn, stored,
maintained and replaced should be explained to
the user.

●

Provide adequate washing facilities.

WHAT SHOULD EMPLOYEES DO?

●

Follow instructions on safe working practices given
by your employers, including the correct use and
adjustment of control measures such as local
extraction ventilation.

●

When required, wear protective equipment such as
respirators. Suitable gloves, protective clothing and
eye protection may also be appropriate for certain
work where splashing of fluxes etc can occur.

●

Report defects in any enclosures, extraction
equipment, protective equipment or other control
measures to your employer.

●

Avoid skin contact with rosin-based solder fluxes, but
if this occurs, wash with soap and water as soon as
possible. A simple skin conditioning cream may be
used after washing and drying.

●

Take part in health checks, which are part of the
required health surveillance programmes. Report
symptoms of respiratory or skin complaints to an
occupational health doctor or nurse if there is one. If
not, see your General Practitioner and tell them what
work you do. Tell your supervisor or other member of
management as well.

●

If you have any concerns about working with rosin-
based solder fluxes tell your occupational health
doctor or nurse, if there is one, or a safety
representative, supervisor or union representative so
that your concerns may be taken up with your
employer.

WHAT ABOUT HEALTH CHECKS?

●

The need for health surveillance should be
considered for all people working in processes where
there is exposure to rosin-based solder fluxes. This will
be determined by the risk assessment under COSHH.

●

A programme of initial and regular health checks for
both respiratory and skin problems may be required.
You should co-operate with your employer and any
occupational health doctor or nurse involved in
carrying out these checks.

●

The initial health check aims to pick out people who
have a medical condition which could be made
worse by exposure to rosin-based solder flux and its
fumes. At the regular health checks you should report
any respiratory or skin complaints and any other
health problems which you think may be related to
your work.

●

If a respiratory or skin problem occurs, you should be
seen by a doctor or nurse with a knowledge of
occupational asthma or skin disease, as
appropriate. When neglected, some health
problems caused by exposure to rosin-based solder
flux and its fume can be disabling and permanent,
requiring a change in occupation.

●

COSHH requires the employer to allow employees,
who have first given reasonable notice, to see their
health record.

WHAT OTHER INFORMATION IS
AVAILABLE FROM HSE BOOKS?

Controlling health risks from rosin (colophony) based
solder fluxes

INDG249 (single copies free;

ISBN 0 7176 1383 6 for priced packs of 10 copies)

General COSHH ACOP (Control of substances hazardous
to health), and Carcinogens ACOP (Control of
carcinogenic substances) and Biological agents ACOP
(Control of biological agents). Control of Substances
Hazardous to Health Regulations 1999. Approved Codes
of Practice

L5 ISBN 0 7176 1670 3

COSHH: A brief guide to the Regulations

INDG136(rev1)

(single copies free; ISBN 0 7176 2444 7 for priced packs
of 10 copies)

Preventing asthma at work: How to control respiratory
sensitisers

L55 ISBN 0 7176 0661 9

Medical aspects of occupational asthma

MS 25

ISBN 0 7176 1547 2

Medical aspects of occupational skin disease

MS 24

ISBN 0 7176 1545 6

While every effort has been made to ensure the
accuracy of the references listed in this publication, their
future availability cannot be guaranteed.

FURTHER INFORMATION

HSE priced and free publications are available by mail
order from HSE Books, PO Box 1999, Sudbury, Suffolk
CO10 2WA Tel: 01787 881165 Fax: 01787 313995 Website:
www.hsebooks.co.uk (HSE priced publications are also
available from bookshops.)

For information about health and safety ring HSE's
InfoLine Tel: 08701 545500 Fax: 02920 859260 e-mail:
hseinformationservices@natbrit.com or write to HSE
Information Services, Caerphilly Business Park,
Caerphilly CF83 3GG. You can also visit HSE’s website:
www.hse.gov.uk

This leaflet contains notes on good practice which
are not compulsory but which you may find helpful in
considering what you need to do.