Section 1 - CHEMICAL PRODUCT AND COMPANY IDENTIFICATION

PRODUCT NAME

HALOSULFURON METHYL

STATEMENT OF HAZARDOUS NATURE

Not considered a hazardous substance according to OSHA 29 CFR 1910.1200.

NFPA

PRODUCT USE

Selective systemic herbicide. Inhibits the action of acetolactate synthase (ALS) which
catalyses the biosynthesis of the essential amino- acids valine, leucine and isoleucine,
thus inhibiting cell division and plant growth. For control of annual broadleaved weeds
and nutsedge spp. in maize, sugarcane, rice and turf.

SYNONYMS

C13-H15-Cl-N6-O7-S, "1H-pyrazole-4-carboxylic acid, 3-chloro-", "1H-pyrazole-4-
carboxylic acid, 3-chloro-", "5-[((((4, 6-dimethoxy-2-
pyrimidinyl)amino)carbonyl)sulfonyl]-1-methyl-, ", "5-[((((4, 6-dimethoxy-2-
pyrimidinyl)amino)carbonyl)sulfonyl]-1-methyl-, ", "methyl ester", "3-chloro-5-(4, 6-
dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-", "3-chloro-5-(4, 6-dimethoxypyrimidin-2-
ylcarbamoylsulfamoyl)-", "1-methylpyrazole-4-carboxylic acid, methyl ester", "1-
methylpyrazole-4-carboxylic acid, methyl ester", "3-chloro-5-[((((4, 6-dimethoxy-2-
pyrimidinyl)amino)carbonyl)amino)sulfonyl]-", "3-chloro-5-[((((4, 6-dimethoxy-2-
pyrimidinyl)amino)carbonyl)amino)sulfonyl]-", "1-methyl-1H-pyrazole-4-carboxylic acid,
methyl ester", "1-methyl-1H-pyrazole-4-carboxylic acid, methyl ester", "A-841101 NC-319
MON-12000", "sulfonylurea herbicide/ pesticide"

Section 2 - HAZARDS IDENTIFICATION

CANADIAN WHMIS SYMBOLS

None

EMERGENCY OVERVIEW

RISK

POTENTIAL HEALTH EFFECTS

ACUTE HEALTH EFFECTS

SWALLOWED

  The material has NOT been classified as "harmful by ingestion". This is because of the lack of corroborating animal or human evidence. The material may still be damaging to the health of the individual, following ingestion, especially where pre-existing organ (e.g. liver, kidney) damage is evident. Present definitions of harmful or toxic substances are generally based on doses producing mortality (death) rather than those producing morbidity (disease, ill-health). Gastrointestinal tract discomfort may produce nausea and vomiting. In an occupational setting however, unintentional ingestion is not thought to be cause for concern.  

EYE

  Although the material is not thought to be an irritant, direct contact with the eye may cause transient discomfort characterized by tearing or conjunctival redness (as with windburn). Slight abrasive damage may also result. The material may produce foreign body irritation in certain individuals.  

SKIN

  The material is not thought to produce adverse health effects or skin irritation following contact (as classified using animal models). Nevertheless, good hygiene practice requires that exposure be kept to a minimum and that suitable gloves be used in an occupational setting.  

INHALED

  The material is not thought to produce adverse health effects or irritation of the respiratory tract (as classified using animal models). Nevertheless, good hygiene practice requires that exposure be kept to a minimum and that suitable control measures be used in an occupational setting.  

CHRONIC HEALTH EFFECTS

  Sulfonylureas, imidazolinones, sulfonoanilides and triazolo-pyrimidines, as herbicides, are used extensively because of their wide-spectrum effects on weeds and their low toxicity to mammals. The effects of these herbicides on plants, micro-algae and bacteria are due to the inhibition of acetolactate synthase (ALS) involved in the synthesis of acetolactic and butyric acids, which are the precursors of the branched-chain amino acids:  isoleucine, leucine and valine.  Mammals also produce these precursor amino-acids using ALS so the potential for toxic effects is apparent though not evident from many studies.  Long term exposure to high dust concentrations may cause changes in lung function i.e. pneumoconiosis; caused by particles less than 0.5 micron penetrating and remaining in the lung. Prime symptom is breathlessness; lung shadows show on X-ray.  Long-term exposure to the product is not thought to produce chronic effects adverse to the health (as classified using animal models); nevertheless exposure by all routes should be minimized as a matter of course.