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Chemical Sampling Information (CSI)
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General Description

Synonyms: Lasso; Acetanilide, 2 - chloro - 2',6' - diethyl - N - (methoxymethyl) -; 2-Chloro-N-(2,6-Diethylphenyl) N-(methoxymethyl) Acetamide; Alamex; Alochlor; CP50144; Metachlor; Methachlor

OSHA IMIS Code Number: 1580

Chemical Abstracts Service (CAS) Registry Number: 15972-60-8

NIOSH Registry of Toxic Effects (RTECS) Identification Number: AE1225000

Chemical Description and Physical Properties: Cream colored solid.
molecular formula: C14H20ClNO2
molecular weight: 269.8
vapor pressure: 0.02 mm at 100 C
melting point: 39.5-41.5 C
Health Factors

Environmental Protection Agency (EPA) carcinogenic classification: Group L1, Likely to be a human carcinogen at high doses but not likely at low doses.

Potential Symptoms: Eye, skin irritation (slight); skin sensitizer (uncommon); SKIN ABS.

Health Effects: Contact dermatitis (HE3).

Affected Organs: Eyes, skin

Notes: 1) OSHA does not have a PEL for alachlor. 2) Alachlor is classified as a Restricted Use Pesticide by the EPA, which describes it as the second leading herbicide in the US, with heavy use on corn and soybean fields. 3) Metabolized by cytochrome P450 3A4 to 2-chloro-N-(2,6-diethylphenyl) acetamide, an intermediate for the production of a putative carcinogenic metabolite not yet identified in humans, 2,6-diethylbenzo-quinone. 4) The urinary metabolite, alachlor mercapturate, was found to be inversely associated with semen quality in one study. 5) A recent study of pesticide spreaders by NCI suggested an increased incidence of lymphohematopoietic cancers (leukemia, multiple myeloma) among those exposed to alachlor, whereas another recent study by Monsanto reported no increase among alachlor manufacturing workers.

Date Last Revised: 11/15/2004

Literature Basis:

  • EPA Consumer Ground Water & Drinking Water Factsheet on: Alachlor.
  • International Chemical Safety Cards (WHO/IPCS/ILO): Alachlor.
  • Acquavella, J.F., Delzell, E., Cheng, H., Lynch, C.F. and Johnson, G.: Mortality and cancer incidence among alachlor manufacturing workers. Occup. Environ. Med. 61(8): 680-685, 2004.
  • Coleman, S., Liu, S., Linderman, R. Hodgson, E. and Rose, R.L.: In vitro metabolism of alachlor by human liver microsomes and human cytochrome P450 isoforms. Chem. Biol. Interact. 122(1): 27-39, 1999.
  • Dearfield, K.L., McCarroll, N.E., Protzel, A., Stack, H.F., Jackson, M.A. and Waters, M.D.: A survey of EPA/OPP and open literature on selected pesticide chemicals. II. Mutagenicity and carcinogenicity of selected chloroacetanilides and related compounds. Mutat. Res. 443(1-2): 183-221, 1999.
  • Lee, W.J.: Cancer incidence among pesticide applicators exposed to alachlor in the Agricultural Health Study. Am. J. Epidemiol. 159(4): 373-380, 2004.
  • Leet, T. et al.: Cancer incidence among alachlor manufacturing workers. Am. J. Ind. Med. 30(3): 300-306, 1996.
  • Sanderson, W.T., Biagini, R., Tolos, W., Henningsen, G. and MacKenzie, B.: Biological monitoring of commercial pesticide applicators for urine metabolites of the herbicide alachlor. Am. Ind. Hyg. Assoc. J. 56(9): 883-889, 1995.
  • Swan, S.H. et al.: Semen quality in relation to biomarkers of pesticide exposure. Environ. Health Perspect. 111(12): 1478-1484, 2003.
  • Won, J.H., Ahn, S.K. and Kim, S.C.: Allergic contact dermatitis from the herbicide Alachlor®. Contact Dermatitis 28(1): 38-39, 1993.
Monitoring Methods used by OSHA

Laboratory Sampling/Analytical Method:

  • sampling media: Glass Fiber Filter (37 mm)
    analytical solvent: Acetonitrile
    maximum volume: 100 Liters
    maximum flow rate:1.0 L/min
    current analytical method: High Performance Liquid Chromatography; HPLC/UV
    method reference: OSHA Analytical Method (OSHA PV2035)
    method classification: Partially Validated

Bulk method: Limit the amount of bulk submitted to one gram or one mL.

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