DETERMINATION ON WHETHER A SUBSTANCE IS A HAZARDOUS
SUBSTANCE PURSUANT TO SECTION 26 OF THE HSNO ACT
Application Code
HAZ03003
Application Type
Section 26 – determine whether a substance is hazardous
under the HSNO Act.
Applicant
Plastics New Zealand (Inc)
Date Application Received
2 April 2003
To be considered by
The Hazardous Substances Standing Committee of the
Authority.
Purpose of the Application
To determine whether certain polyamides are hazardous
Applications Advisor (Operations
Group)
Noel McCardle
Scientific Advisor (Science &
Analysis Group)
Tania van Maanen
Introduction
Polyamides are a class of polymers that have recurring amide groups as an integral part of the
main polymer backbone. For the purposes of this s26 determination, no heteroatoms may be
present other than those comprising the (amide) linkage. They are more commonly known as
nylons and are synthesized from intermediates such as dicarboxylic acids, diamines, amino acids
and lactams. Nylons form fibres easily and are used in a wide range of applications eg clothing,
house furnishings, automotive parts, parachutes, ropes and nets and packaging. The aromatic
polyamides (aramids) are a special subgroup of the polyamides which have benzene rings
between the amide bonds rather than aliphatic carbon chains. Aramids are tough, flame resistant
and durable fibres and are marketed under such names as Kevlar® and Nomex®.
No polymer manufacture is currently undertaken in New Zealand. Plastics are imported into the
country in the form of granules from which a range of products are manufactured. Manufactured
articles are exempt from the HSNO approval process but polymer granules fall within the HSNO
definition of a substance and as such, a HSNO approval is required if any of the HSNO hazardous
property thresholds is exceeded.
Substance Definition
Polyamides are a class of polymers that have recurring amide groups as an integral part of the
main polymer backbone. For the purposes of this s26 determination, no heteroatoms may be
present other than those comprising the amide linkage. Further, the definition is limited to those
polyamides (not containing additives) with a number average molecular weight greater than 10
000 amu and with residual monomer, catalyst and solvent impurities present at levels less than
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0.1%. In addition, polymers that are cationic (or potentially cationic) or those that are water
absorbing, are specifically excluded from this definition.
Examples of polyamides are listed in the application form HS7, provided as Appendix 1 to this
document.
Hazardous Property Assessment
An assessment of polyamides against the HSNO thresholds was provided in the application form
(attached as Appendix 1 to this document). It is noted that often limited or no information was
available on these types of substances for a number of endpoints, especially data on polyamides
as a group. Where information was available on specific polyamides, this has been provided.
However, it is recognised that this s26 determination is limited to polyamides of very high
molecular weight (i.e. greater than10 000 amu) and as discussed in the application form, such
substances are not likely to be bioavailable and therefore highly unlikely to adversely affect either
human health or the environment.
A summary of the hazardous property assessment is provided below.
Class / Sub-class
Detail
Threshold
Class 1 – Explosiveness
Polyamides are not considered explosive. They do
not meet the HSNO criteria for an explosive
substance and are not listed in the UN
Recommendations on the Transport of Dangerous
Goods.
Not triggered
Class 2,3,4 – Flammability
Polyamides are not considered flammable. They do
not meet the HSNO criteria for a flammable
substance and are not listed in the UN
Recommendations on the Transport of Dangerous
Goods.
Not triggered
Sub-class 5.1 – Oxidisers
Polyamides do not meet the HSNO definition/criteria
for an oxidising substance.
Not triggered
Subclass 5.2 – Organic
peroxides
Polyamides do not meet the HSNO definition/criteria
for an organic peroxide.
Not triggered
Sub-class 6.1 – Acute toxicity
Polyamides are not considered to be acutely toxic as
defined by the HSNO criteria. It has been reported
that polyamide plastics have no known toxic effects.
Rats fed Nylon 6 at 12500 mg/kg and Nylon 6,12 at
5000 mg/kg showed no adverse effects. Another
acute oral study reported no mortalities when rats
were fed up to 7500 mg/kg of Kevlar®.
Not triggered
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Class / Sub-class
Detail
Threshold
Sub-class 6.3 – Skin irritancy
Polyamides are not considered to be skin irritants as
defined by the HSNO criteria. In a skin irritation
study, a group of 100 subjects exposed to nylon for
ten 24 hour applications followed by a 24 hour
challenge after a two week rest period showed no
reaction. Two skin irritation studies of Nomex® had
negative results.
Not triggered
Sub-class 6.4 – Eye irritancy
No information was located to indicate that
polyamides would be eye irritants as defined by the
HSNO criteria.
Not triggered
Sub-class 6.5A – Respiratory
sensitisation
No information was located to indicate that
polyamides would be respiratory sensitisers as
defined by the HSNO criteria.
Not triggered
Sub-class 6.5B – Contact
sensitisation
No information was located to indicate that
polyamides would be contact sensitisers as defined
by the HSNO criteria. Two skin sensitisation studies
of Nomex® had negative results.
Not triggered
Sub-class 6.6 – Mutagenicity
No information was located to indicate that
polyamides would be mutagenic as defined by the
HSNO criteria.
Not triggered
Sub-class 6.7 –
Carcinogenicity
No information was located to indicate that
polyamides would be carcinogenic as defined by the
HSNO criteria. The International Agency for
Research on Cancer (IARC) has classified Nylon 6
and p-aramid fibrils as class 3 substances
[unclassifiable as to carcinogenicity to humans] i.e.
i.e. not unclassifiable as a carcinogen under HSNO.
Not triggered
Sub-class 6.8 – Reproductive
/ developmental effects
No information was located to indicate that
polyamides would be reproductive/developmental
toxicants as defined by the HSNO criteria. Tests on
Nylon 12 reported no toxic effects on reproductive
function, embryos, or offspring development.
Not triggered
Sub-class 6.9 – Target organ
systemic effects
No information was located to indicate that
polyamides would be target organ systemic toxicants
as defined by the HSNO criteria. Long term rat and
dog feeding studies of Nylon 6, Nylon 6,6 and Nylon
6,12 show no adverse physiological effects. In a
separate feeding study involving Nylon 11, rats fed
doses up to 5000 mg/kg bw/day and dogs fed doses
up to 2500 mg/kg bw/day showed no toxic effects.
Not triggered
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Class / Sub-class
Detail
Threshold
Class 8 – Corrosivity
Polyamides are not considered to be corrosive to
metals (sub-class 8.1), to skin (sub-class 8.2) or to
the eye (sub-class 8.3). Polyamides are not listed in
the UN Recommendations on the Transport of
Dangerous Goods.
Not triggered
Class 9 - Ecotoxicity
Polyamides are not considered to be ecotoxic due to
their low reactivity and high molecular weight. As
such, they will not be bioavailable and therefore
highly unlikely to adversely affect aquatic life (subclass 9.1), soil organisms (sub-class 9.2) terrestrial
vertebrates (subclass 9.3) or terrestrial invertebrates
(sub-class 9.4). Although polyamides may not be
rapidly biodegradable, they will not bioaccumulate
due to their low bioavailablitiy.
Not triggered
Other information
As discussed in the application form (attached as Appendix 1 to this document), polyamides of
molecular weight > 10,000 meet the USEPA polymer exemption rule and the NICNAS polymers
of low concern criteria. Furthermore, various polyamides are permitted by the US Food and Drug
Administration (USFDA) “as articles or components of articles intended for use in contact with
food” (CFR Title 21 paragraphs 177.1500, 177.1632, 177.2355).
Recommended Determination
If the Authority is of the view that polyamides are not hazardous under the HSNO Act,
then the Authority may:
a) determine that polyamides as defined are not hazardous pursuant to section 26 of the
HSNO Act 1996; and
b) direct the Chief Executive to arrange for notice of this determination to be placed in
the Gazette.
Dr Donald Hannah, Manager, Science and Analysis
Date: 10 July 2003
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Determination by the Authority
The recommended determination is approved.
Mr Tony Haggerty, Chair Hazardous Substances Standing Committee
Date: 30 July 2003
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Appendix 1
Application form HAZ03003 (attached)
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