Formaldehyde.... its safe use in foundries
This leaflet gives advice on current good
Phenol formaldehyde and urea formaldehyde resins
are used extensively in the hot box and warm box processes to
produce cores and moulds. The resins are mixed with a catalyst
and sand which when heated, hardens to form a mould or
At normal temperatures these resins do not give off vapour but
when they are heated, formaldehyde is evolved which is a
potential respiratory sensitiser and has been shown in
experiments to cause cancer in animals. It is not however a
proven human carcinogen. Formaldehyde can irritate the eyes, skin
and respiratory tract and prolonged exposure could cause skin
sensitisation and allergic contact dermatitis.
How to reduce risk
When using formaldehyde resins which are heated, local exhaust
ventilation may be necessary.
Any worker who is involved in the use, storage or transport of
these resins needs to be instructed on the associated dangers and
necessary precautions. This may include the proper use of
goggles, PVC gloves and aprons, and footwear.
Complying with workplace exposure limits
The current workplace exposure limit (WEL) for formaldehyde is two parts per million (2ppm), time weighted average over eight hours. The short-term limit (averaged over ten minutes) is 2ppm.
The WEL for formaldehyde is currently under review and subject to possible change.
A worker's exposure to formaldehyde should not exceed this WEL and every effort should be made to reduce the exposure as low as is reasonably practicable, and in any case below the WEL.
Regular checking and maintenance
It is advisable that local exhaust ventilation used to control
exposure is subject to frequent checks for damage, in addition to
the routine testing and examination, to ensure that it is
The duty of suppliers
Suppliers have a duty to ensure, so far as is reasonably
practicable, that the chemicals that they supply are safe and
present no health risks when properly used, handled, processed,
stored or transported. They must provide customers with a
description of the hazards involved and safety precautions
necessary to overcome those hazards. This advice usually comes in
the form of product safety data sheets and users are advised
always to request copies from suppliers.
Advice given in these safety data sheets may form the basis
for training and instruction given to employees.
Safe labelling and storage
Containers of formaldehyde resins should be properly labelled,
stored in an area surrounded by a low sill to retain leaks and
spills and protected from damage by passing traffic. They should
also be stored separately from any catalysts, hardeners or
sources of heat.
Dealing with spillages
Prompt action is required to deal with spillages and leaks.
Suitable supplies of decontaminating materials should be kept
available and employees adequately instructed on dealing safely
with such situations.
Provision needs to be made for the subsequent decontamination
of all protective clothing and equipment used in the clean
Empty drums and containers should be properly labelled and
stored in a safe place until they can be taken away by an
authorised contractor for proper disposal. Alternatively,
suitable arrangements may be made with the supplier for the
collection of empty containers and drums.
Other available information
This leaflet was produced by the Foundries Industry Advisory Committee which advises on the protection of foundry workers from hazards to their health and safety while at work.
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This publication may be freely reproduced, except for advertising, endorsement or sale purposes. The information it contains is current at 04/07. Please acknowledge the source as HSE.
Published by the Health and Safety Executive