Section 1 - CHEMICAL PRODUCT AND COMPANY IDENTIFICATION

PRODUCT NAME

MALDISON MONOCARBOXYLIC ACID

NFPA

PRODUCT USE

Insecticide.

SYNONYMS

C8-H15-O6-P-S2, C8-H15-O6-P-S2, "malathion monoacid", "butanedioic acid,
[(dimethoxyphosphinothioyl)thio]-, monoethyl ester",
"[(dimethoxyphosphinothioyl)thio]butanedioic acid monoethyl ester", "succinic acid,
mercapto-, monoethyl ester, S-ester with O, O-dimethyl-phosphorodithioate", "succinic
acid, mercapto-, monoethyl ester, S-ester with O, O-dimethyl-phosphorodithioate",
"mercaptosuccinic acid ethyl ester, S-ester with O, O-dimethylphosphorodithioate",
"mercaptosuccinic acid ethyl ester, S-ester with O, O-dimethylphosphorodithioate",
"mercaptosuccinic acid ethyl ester 4-ethyl ester S-ester with O, O-
dimethylphosphorodithioate", "mercaptosuccinic acid ethyl ester 4-ethyl ester S-ester
with O, O-dimethylphosphorodithioate", "monocarboxylic acid of malathion", "succinic acid,
mercapto-, ethyl ester, S-ester with O, O-dimethylphosphorodithioate", "succinic acid,
mercapto-, ethyl ester, S-ester with O, O-dimethylphosphorodithioate", "succinic acid,
mercapto-, ethyl ester, O, O-dimethyl phosphorothioate", "succinic acid, mercapto-,
ethyl ester, O, O-dimethyl phosphorothioate", insecticide

Section 2 - HAZARDS IDENTIFICATION

CANADIAN WHMIS SYMBOLS

EMERGENCY OVERVIEW

RISK

POTENTIAL HEALTH EFFECTS

ACUTE HEALTH EFFECTS

SWALLOWED

  Although ingestion is not thought to produce harmful effects, 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, ingestion of insignificant quantities 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 produce transient discomfort characterized by tearing or conjunctival redness (as with windburn).  Direct eye contact can produce tears, eyelid twitches, pupil contraction, loss of focus, and blurred or dimmed vision. Dilation of the pupils occasionally occurs.  

SKIN

  Skin contact with the material may damage the health of the individual; systemic effects may result following absorption.  The material is not thought to be a skin irritant (as classified using animal models). Temporary discomfort, however, may result from prolonged dermal exposures. Good hygiene practice requires that exposure be kept to a minimum and that suitable gloves be used in an occupational setting.  Toxic effects may result from skin absorption.  Sensitization may result in allergic dermatitis responses includingrash, itching, hives or swelling of extremities.  There may be sweating and muscle twitches at site of contact. Reaction may bedelayed by hours.  

INHALED

  Inhalation may produce health damage*.  The material is not thought to produce respiratory irritation (as classified using animal models). Nevertheless inhalation of the material, especially for prolonged periods, may produce respiratory discomfort and occasionally, distress.  Poisoning due to cholinesterase inhibitors causes symptoms such as increased blood flow to the nose, watery discharge, chest discomfort, shortness of breath and wheezing. Other symptoms include increased production of tears, nausea and vomiting, diarrhea, stomach pain, involuntary passing of urine and stools, chest pain, breathing difficulty, low blood pressure, irregular heartbeat, loss of reflexes, twitching, visual disturbances, altered pupil size, convulsions, lung congestion, coma and heart failure. Nervous system effects include inco-ordination, slurred speech, tremors of the tongue and eyelids, and paralysis of the limbs and muscles of breathing, which can cause death, although death is also seen due to cardiac arrest.  

CHRONIC HEALTH EFFECTS

  Principal routes of exposure are by accidental skin and eye contact andinhalation of generated dusts.  Repeated or prolonged exposures to cholinesterase inhibitors produce symptoms similar to acute effects. In addition workers exposed repeatedly to these substances may exhibit impaired memory and loss of concentration, severe depression and acute psychosis, irritability, confusion, apathy, emotional liability, speech difficulties, headache, spatial disorientation, delayed reaction times, sleepwalking, drowsiness or insomnia. An influenza-like condition with nausea, weakness, anorexia and malaise has been described. There is a growing body of evidence from epidemiological studies and from experimental laboratory studies that short-term exposure to some cholinesterase-inhibiting insecticides may produce behavioral or neuro- chemical changes lasting for days or months,  presumably outlasting the cholinesterase inhibition. Although the number of adverse effects following humans poisonings subside, there are still effects in some workers months after cholinesterase activity returns to normal. These long-lasting effects include blurred vision, headache, weakness, and anorexia. The neurochemistry of animals exposed to chlorpyrifos or fenthion is reported to be altered permanently after a single exposure. These effects may be more severe in developing animals where both acetyl- and butyrylcholinesterase may play an integral part in the development of the nervous system. Padilla S., The Neurotoxicity of Cholinesterase-Inhibiting Insecticides: Past and Present Evidence Demonstrating Persistent Effects. Inhalation Toxicology 7:903-907, 1995.