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





ETHYL MERCAPTAN								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:** 75-08-1; **Chemical Formula:** C2H5SH
OSHA previously had a ceiling limit of 10 ppm for ethyl mercaptan. An 8-hour TWA limit of 0.5 ppm was proposed for this substance, based on the ACGIH (1986/Ex. 1-3) recommendation; NIOSH (Ex. 8-47, Table N1) concurred with OSHA’s proposal. The final rule establishes a PEL of 0.5 ppm as an 8-hour TWA for ethyl mercaptan. Ethyl mercaptan is a colorless liquid with a persistent and penetrating leek-like odor.
Acute animal toxicity data concerning ethyl mercaptan are taken from a single study that reports the following findings. The 4-hour inhalation LC(50) values in rats and mice are 2770 ppm and 4420 ppm, respectively. In the rat, the intraperitoneal LD(50) is reported to be approximately 450 mg/kg. One drop applied to rabbit eyes caused only slight irritation, but high concentrations of vapor caused considerable irritation within 15 minutes. Maximal sublethal intraperitoneal doses have been reported to induce deep sedation, with higher exposures causing restlessness, muscular incoordination, skeletal muscular paralysis, cyanosis, respiratory depression, coma, and death. Although inhalation tests showed no noteworthy pathology in rats, intraperitoneal injection caused lymphatic infiltration of the liver with occasional necrosis (Fairchild and Stokinger 1958/Ex. 1-415). In chronic inhalation studies of rabbits, rats, and mice, a five-month exposure to 40 ppm caused minimal cardiovascular and other systemic effects (Blinova 1965/Ex. 1-603).
Studies of human volunteers, exposed at 4 ppm for three hours daily for 5 to 10 days, have reported adverse effects. At this level, all subjects experienced altered taste and olfactory reactions, periodic nausea, mucous membrane irritation, and fatigue. Exposure to 0.4 ppm produced no unpleasant symptoms (ACGIH 1986/Ex. 1-3, p. 262).
The Workers Institute for Safety and Health (WISH) (Ex. 116) was critical of OSHA’s proposal to establish an 8-hour TWA limit rather than a STEL or ceiling for ethyl mercaptan. OSHA believes that the health evidence on ethyl mercaptan shows that a 0.5 ppm TWA limit will be sufficient to reduce the adverse acute effects associated with exposure to this substance; for example, a 3-hour exposure to 4 ppm, which caused adverse acute effects in human volunteers (ACGIH 1986/Ex. 1-3, p. 262), would exceed 0.5 ppm as an 8-hour TWA. The health evidence discussed above demonstrates that, at the previous PEL of 10 ppm (ceiling), employees were at risk of nausea, fatigue, and irritation; these effects have been demonstrated to occur on exposure to 4-ppm concentrations of this substance for just a few days. OSHA considers these exposure-related effects of nausea, fatigue, and irritation to be material impairments of health. The Agency concludes that the revised limit of 0.5 ppm will substantially reduce this significant risk. Therefore, OSHA is lowering its limit for ethyl mercaptan to 0.5 ppm as an 8-hour TWA.
										
							
								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