Parathion

Synonyms & Trade Names

O,O-Diethyl-O(p-nitrophenyl) phosphorothioate, Diethyl parathion, Ethyl parathion, Parathion-ethyl

CAS No.

56-38-2

RTECS No.

TF4550000

DOT ID & Guide

2783 152

Formula

(C₂H₅O)₂P(S)OC₆H₄NO₂

Conversion

IDLH

10 mg/m³
See: 56382

Exposure Limits

NIOSH REL

TWA 0.05 mg/m³ [skin]

OSHA PEL

TWA 0.1 mg/m³ [skin]

Measurement Methods

NIOSH 5600;
OSHA 62
See: NMAM or OSHA Methods

Physical Description

Pale-yellow to dark-brown liquid with a garlic-like odor. [Note: A solid below 43°F. Pesticide that may be absorbed on a dry carrier.]

Molecular Weight

291.3

Boiling Point

707°F

Freezing Point

43°F

Solubility

0.001%

Vapor Pressure

0.00004 mmHg

Ionization Potential

Specific Gravity

1.27

Flash Point

(oc) 392°F

Upper Explosive Limit

Lower Explosive Limit

Class IIIB Combustible Liquid: Fl.P. at or above 200°F.

Incompatibilities & Reactivities

Strong oxidizers, alkaline materials

Exposure Routes

inhalation, skin absorption, ingestion, skin and/or eye contact

Symptoms

irritation eyes, skin, respiratory system; miosis; rhinorrhea (discharge of thin nasal mucus); headache; chest tightness, wheezing, laryngeal spasm, salivation, cyanosis; anorexia, nausea, vomiting, abdominal cramps, diarrhea; sweating; muscle fasciculation, lassitude (weakness, exhaustion), paralysis; dizziness, confusion, ataxia; convulsions, coma; low blood pressure; cardiac irreg

Target Organs

Eyes, skin, respiratory system, central nervous system, cardiovascular system, blood cholinesterase

Personal Protection/Sanitation

(See protection codes)
Skin:Prevent skin contact
Eyes:Prevent eye contact
Wash skin:When contaminated
Remove:When wet or contaminated
Change:Daily
Provide:Eyewash, Quick drench

First Aid

(See procedures)
Eye:Irrigate immediately
Skin:Soap wash immediately
Breathing:Respiratory support
Swallow:Medical attention immediately

Respirator Recommendations

NIOSH

Up to 0.5 mg/m³:
(APF = 10) Any air-purifying half-mask respirator with organic vapor cartridge(s) in combination with an N95, R95, or P95 filter. The following filters may also be used: N99, R99, P99, N100, R100, P100.
Click here for information on selection of N, R, or P filters.
(APF = 10) Any supplied-air respirator

Up to 1.25 mg/m³:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode
(APF = 25) Any powered, air-purifying respirator with an organic vapor cartridge in combination with a high-efficiency particulate filter.

Up to 2.5 mg/m³:
(APF = 50) Any air-purifying full-facepiece respirator equipped with organic vapor cartridge(s) in combination with an N100, R100, or P100 filter.
Click here for information on selection of N, R, or P filters.
(APF = 50) Any supplied-air respirator that has a tight-fitting facepiece and is operated in a continuous-flow mode
(APF = 50) Any powered, air-purifying respirator with a tight-fitting facepiece and organic vapor cartridge(s) in combination with a high-efficiency particulate filter
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece

Up to 10 mg/m³:
(APF = 1000) Any supplied-air respirator operated in a pressure-demand or other positive-pressure mode

Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister having an N100, R100, or P100 filter.
Click here for information on selection of N, R, or P filters.
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

Parathion

NIOSH REL

OSHA PEL

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