Priority Existing Chemical Assessment Reports -

Acrylonitrile

 

1. Chemical Identity

1.1. Chemical name (IUPAC)

• 2-Propenenitrile

1.2. Registry numbers

Acrylonitrile is listed on the Australian Inventory of Chemical Substances (AICS) as 2-propenenitrile.

• CAS number 107-13-1

• EINECS number 203-466-5

• RTECS number AT5250000

• UN number 1093

1.3. Other names

• Acrylonitrile monomer

• Cyanoethene

• Cyanoethylene

• Propenenitrile

• Vinyl cyanide

• Vinylcyanide

1.4. Trade names

• Acrylonitrile inhibited

2. Applicants

BASF Australia Ltd
500 Princes Hwy
Noble Park VIC 3174

Dow Chemical (Australia) Pty Ltd
541-583 Kororoit Creek Rd
Altona VIC 3018

Bio-Scientific Pty Ltd
28 Monro Ave
Kirrawee NSW 2232

Huntsman Chemical Company Australia Pty Ltd
Somerville Rd
West Footscray VIC 3012

Crown Scientific Pty Ltd
144 Moorebank Ave
Moorebank NSW 2170

Labax International Pty Ltd
23/199 Pacific Hwy
North Sydney NSW 2006

Cytec Australia Holdings Pty Ltd
Suite 1, 7-11 Railway St
Baulkham Hills NSW 2153

Sigma-Aldrich Pty Ltd
2114 Anella Ave
Castle Hill NSW 2154

3. Acrylonitrile Preliminary Assessment Overview

Background

Acrylonitrile was declared a Priority Existing Chemical for preliminary assessment on 7 April 1998 because of public concern about the health effects of the chemical. The focus of the assessment was on use and exposure in Australia.

Import and use

Imports of acrylonitrile amount to approximately 2000 tonnes per year. Seventy per cent is used at a single site for the manufacture of a polymer, which is further compounded to plastic resins. Five companies process the remainder to polymer emulsions. About 13,000 tonnes of acrylonitrile-based plastic resins containing <0.005% residual acrylonitrile are imported per annum. Import figures were not available for acrylonitrile-based plastic articles or fibres and fabrics, which contain from 0.0001-0.005% residual acrylonitrile.

Properties

For this assessment, the physico-chemical, toxicological and environmental properties of acrylonitrile have been summarised from peer-reviewed hazard assessments by international organisations such as the International Agency for Research on Cancer, the International Program for Chemical Safety and the Organisation for Economic Co-Operation and Development.

In Australia, acrylonitrile is classified as highly flammable; toxic by inhalation, in contact with skin and if swallowed; a skin irritant; and a carcinogen in Group 2 (substances regarded as if they are carcinogenic to humans). Recently, the European Communities have agreed to amend their classification to include irritation of the respiratory system, serious damage to the eyes, and skin sensitisation. Australia will adopt this amendment into the National Occupational Health and Safety Commission's List of Designated Hazardous Substances according to the usual process.

Acrylonitrile is readily to fairly degradable in water, soil and in the troposphere. Its toxicity to aquatic vertebrates and invertebrates, algae and aquatic plants is slight to moderate. Bioaccumulation is expected to be slight to negligible.

Occupational health and safety

Industrial use of the chemical is tightly controlled by a number of national standards and codes and corresponding State and Territory legislation enforced through a system of conditional permits, licences and warrants.

Occupational exposure to acrylonitrile is minimised through rigid process isolation together with engineering controls to reduce emissions, waste streams and leaks from the closed system. Workers routinely use eye/skin protection and respiratory protection is deployed where isolation cannot be maintained. Safety measures and emergency plans aiming to reduce the likelihood and impact of fires, explosions and spills are in place at all sites storing bulk acrylonitrile.

Of 187 breathing zone air samples collected in 1991-99 during normal, fully enclosed transfer or processing operations, only two (1.1 %) exceeded the national exposure standard of 2 ppm (8 h time-weighted average). Sixty-eight per cent were <0.1 ppm, 95% <0.5 ppm and 97% <1 ppm. During sampling or maintenance work, short-term levels in the worker's breathing zone from 0.1-300 ppm have been recorded. However, in these situations workers wear respiratory protective equipment. In industries processing polymers containing only residual amounts of the chemical, exposure levels are expected to be <0.02-0.1 ppm.

Public health

In accordance with Standard for the Uniform Scheduling of Drugs and Poisons, acrylonitrile must not be possessed, sold or supplied for domestic purposes. Consumer exposure to acrylonitrile from skin contact with acrylic fibres and from ingestion of foods contaminated with residual acrylonitrile in packaging materials is estimated at a maximum of 2.2 and 33 ng/kg/day respectively. Indirect exposure via the environment is likely to be less than 100 ng/kg/day. As such, total public exposure would be several orders of magnitude lower than the no observed adverse effect level for any toxicological end-point in laboratory animals.

Environment

There are no Australian data on acrylonitrile levels in air, water or soil. In a worst-case scenario, predicted environmental concentrations from acrylonitrile processing operations are 0.31 mg/L in effluents from sewage treatment plants and 0.00046 ppm in air at 100 meters from atmospheric emission sources. Overseas assessments and a crude comparison of the predicted environmental concentration in water and the effects on aquatic organisms suggest that acrylonitrile is of low concern for the environment.

Recommendations

Although occupational exposure levels are generally low, acrylonitrile is a possible human carcinogen and it is therefore recommended that industry continue to strive to improve their process and engineering controls and atmospheric monitoring programs. Other recommendations concern the revision of communication materials to comply with the impending amendment of the hazard classification of acrylonitrile, the inclusion of laboratory staff in training and monitoring programs, and the need to update the industry Code of Practice for the Safe Use of Acrylonitrile.

On the basis of the known hazards, assessed exposure information and current controls, NICNAS does not recommend a full (risk) assessment of acrylonitrile at this time.