Skip directly to site content Skip directly to page options Skip directly to A-Z link


Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People
														Search
		×
			NIOSH
			NIOSH
				All CDC
				Submit
			For a full list of topics:A-Z Index
			Advanced Search
		Advanced Search


The National Institute for Occupational Safety and Health (NIOSH)


Facebook
        Twitter
        LinkedIn
        Syndicate





DICROTOPHOS								Related Pages
										*OSHA comments from the January 19, 1989 Final Rule on Air Contaminants Project extracted from 54FR2332 et. seq. This rule was remanded by the U.S. Circuit Court of Appeals and the limits are not currently in force.*
**CAS:** 141-66-2; **Chemical Formula:** C8H16NO5P
Previously, OSHA had no limit for dicrotophos; the ACGIH has a TLV of 0.25 mg/m3 TWA, with a skin notation, for this brown liquid with a mild ester odor. The proposed PEL was 0.25 mg/m3, with a skin notation; NIOSH (Ex. 8-47, Table N1) concurs that this limit is appropriate. The final rule establishes an 8-hour TWA of 0.25 mg/m3 and a skin notation.
Dicrotophos is a cholinesterase inhibitor (ACGIH 1986/Ex. 1-3, p. 193). The acute oral LD(50) in rats is reported as 22 mg/kg, and the percutaneous LD(50) in rabbits is 224 mg/kg (Stanford Research Institute 1962, as cited in ACGIH 1986/Ex. 1-3, p. 193). Another study reports the oral LD(50) in rats as 16 to 21 mg/kg and the dermal LD(50) in the same species as 42 mg/kg (Gaines 1969/Ex. 1-320). Two-year feeding studies in rats given 0, 1, 10, or 100 ppm dicrotophos showed no detectable effects at the 1-ppm concentration. At the higher concentrations, decreased body weights (as compared with those of controls) and cholinesterase inhibition were observed (Woodard Research Corporation 1967, as cited in ACGIH 1986/Ex. 1-3, p. 193). Dietary studies in dogs showed both plasma and erythrocyte cholinesterase inhibition at a 16-ppm concentration, but no significant ill effects at concentrations of 0, 0.16, or 1.6 ppm (Woodard Research Corporation 1967, as cited in ACGIH 1986/Ex. 1-3, p. 193). Studies of vapor inhalation in male rats have shown that transient illness occurred after a one-hour exposure to 910 mg/m3 of technical dicrotophos, and to 2620 mg/m3 or 2120 mg/m3 of 38-percent dicrotophos (Kettering Laboratories 1965, as cited in ACGIH 1986/Ex. 1-3). Dicrotophos does not cause demyelinization in chickens (Tunstall Laboratory 1965 and Kettering Laboratory 1963, both as cited in ACGIH 1986/Ex. 1-3, p. 193), and it is metabolized in a fashion similar to mono-microtophos (Menzer and Casida 1965/Ex. 1-986). Only NIOSH commented on dicrotophos.
The proposed PEL was based on the data described above and, in part, by analogy with other cholinesterase-inhibiting substances. In the final rule, OSHA is establishing an 8-hour TWA permissible exposure limit of 0.25 mg/m3, with a skin notation, for dicrotophos. The Agency concludes that this limit will protect workers from the material impairments of health, such as cholinesterase inhibition, potentially associated with inhalation, ingestion, and dermal exposure to this substance at the levels formerly permitted by the absence of a limit. OSHA has determined that these limits will substantially reduce this significant risk.
										
							
								Page last reviewed:  September 28, 2011						Content source:  	National Institute for Occupational Safety and Health NIOSH
1988 OSHA PEL Project Documentation
Index of Chemical Names
Index of CAS Numbers Follow NIOSH Facebook
Pinterest
Twitter
YouTube
 NIOSH Homepage NIOSH A-Z
Workplace Safety & Health Topics
Publications and Products
Programs
Contact NIOSH


About CDC
					Contact Us
					800-232-4636
 Facebook Twitter Instagram LinkedIn Youtube Pinterest Snapchat
 CONTACT CDC
				Contact Us
							Call 800-232-4636
							Email Us
			ABOUT CDC
				About CDC
							Jobs
							Funding
			POLICIES
				Accessibility
							External Links
							Privacy
							Policies
							No Fear Act
							FOIA
							OIG
							Nondiscrimination
							Vulnerability Disclosure Policy
			CONNECT WITH US
				Facebook
								Twitter
								Instagram
								LinkedIn
							Youtube
								Pinterest
								Snapchat
								Email
			LANGUAGES
				Español
							繁體中文
							Tiếng Việt
							한국어
							Tagalog
							Русский
							العربية
							Kreyòl Ayisyen
							Français
							Polski
							Português
							Italiano
							Deutsch
							日本語
							فارسی
							English


U.S. Department of Health & Human Services
			Accessibility
			External Links
			Privacy
			Policies
			No Fear Act
			FOIA
			Nondiscrimination
			OIG
			Vulnerability Disclosure Policy
			USA.gov


Exit Notification / Disclaimer Policy Close
 Links with this icon  indicate that you are leaving the CDC website. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
				Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
				You will be subject to the destination website's privacy policy when you follow the link.
				CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Website Disclaimers
 Cancel Continue