(d) For the definition and the application of the Permissible Exposure Limit (PEL), refer to section 5155(b) and (c)(1). (e) Parts of gas or vapor per million … WORKPLACE EXPOSURE LIMITS OSHA: The legal airborne permissible exposure limit (PEL) is 10 ppm, not to be exceeded at any time. Suitable products for Methyl mercaptan CH 4 S. Whether portable gas detectors, gas detection tubes or personal protective equipment - Dräger offers a comprehensive portfolio to protect you when handling hazardous substances. Little is known about the health effects of this compound. METHYL MERCAPTAN | CAMEO Chemicals | NOAA AEGLs represent threshold exposure limits for the general public and are applicable to emergency exposure periods ranging from 10 minutes (min) to 8 hours (h). 4 Perchloromethyl Mercaptan 1. Alarm detectors should be used when toxic gases may be released. 1980 tn C4 0.0005 0.00025 o O E2 1.1 0.56 Synonyms are isocyanatomethane, methyl carbylamine and MIC. Inhalation. A very dangerous aspect of hydrogen sulfide exposure results from ... there is a potential to exceed the exposure limits … 2 Methyl Mercaptan Acute Exposure Guideline Levels | Acute ... Thiomethane, mercaptomethane, methyl sulphhydrate Mercaptan *Call emergency numbers 24 hours a day only for spills, leaks, fire, exposure, or accidents involving this product. Consider the use of a work permit system e.g. Exposure Guidelines This product does not contain any hazardous materials with occupational exposure limitsestablished by the region specific regulatory bodies. Exposure limit(s) NIOSH REL: C 0.5 ppm (1 mg/m3) [15-minute] OSHA PEL: C 10 ppm (20 mg/m3) IDLH 150 ppm: Poison_Class: 4: Exposure effects: May cause liver and kidney damage. Do not use the Altair5X PID Detector if the exposure limit for the target ... methyl mercaptan METHMERC Methanethiol 74-93-1 CH4 S 9.44 0.6 methyl methacrylate MEMEACRY 80-62-6 C5H8O2 9.7 1.5 COMPOUND NAME Display Name Synonym(s) CAS Number 1 Methyl Mercaptan Standard Safety Data Sheet according to Regulation (E C) No. Under the authority of the Federal Advisory Committee Act (FACA) P.L. Methyl mercaptan. 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. Methyl Mercaptan 74-93-1 Methemoglobin: 1.5 % Hb (In blood) During or at the end of the shift 2010-03-01 Engineering measures Adequate ventilation to control airborned concentrations below the exposure guidelines/limits. If methyl mercaptan is in the gaseous form, stop the flow of gas. 50of 675 ppm was reported for male and female rats exposed to methyl mercaptan for 4 hours (Tansy et al. Articles of … (e) Parts of gas or vapor per million … 71: 0.5-10 strokes, 0.1-140 ppm range, uncertainty 16% for 2.5-20 ppm, 8% for 20-70 ppm. EXPOSURE LIMITS (8 HOUR TWA): (Refer to Section 3). Personal Precautions, Protective Equipment and Emergency Procedures The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website. manufacturing building.d They died from a combination of asphyxia and acute exposure (by inhalation) to methyl mercaptan. TIME WEIGHTED AVERAGE EXPOSURE LIMIT SYMPTOMS OF EXPOSURE TOXICOLOGICAL PROPERTIES RECOMMENDED FIRST AID TREATMENT Methyl Mercaptan Methyl mercaptan (D.O.T. On this page you will be able to access individual Acute Exposure Guideline Level (AEGLs) values that are intended to protect most individuals in the general population, including those that might be particularly susceptible to the harmful effects of the chemicals. 453/2010 ... Where exposure through inhalation may occur from use, respiratory protection equipment is ... Explosion limits : No data available 9.2. At this time, the other constituents have no known exposure limits. 2. 58 / Monday, March 26, 2012 / Rules and Regulations 04/22/2015 EN (English US) SDS ID: 50006 / P/N 3471 4/1 SECTION 8: Exposure controls/personal protection 8.1. Find AEGL values in the table below using the chemical name or its CAS number. NIOSH: The recommended airborne exposure limit is 0.5 ppm, not to be exceeded during any 15 minute work period. Methyl isocyanate is an intermediate chemical in the production of carbamate pesticides (such as carbaryl, carbofuran, methomyl, and aldicarb).It has also been used in the production of rubbers and adhesives.As a highly toxic and … Sources and Routes of Exposure . n-Dodecyl Methyl Sulfide : slight irritation. However, no deaths (O/10) occurred in rats exposed to 400 ppm for 4 hours, and there was 100% mortality at 700 ppm and above. When skin contact also occurs, you may be overexposed, even The mercaptan compounds listed above are added in trace amounts (typically about 2 parts per million) to odorize the natural gas for safety purposes. The main tox… Inhalation is the major route of exposure to methyl mercaptan. For routine information, contact your supplier or Praxair sales representative. § 1910.1000 Air contaminants. Thiomethane, mercaptomethane, methyl sulphhydrate Mercaptan *Call emergency numbers 24 hours a day only for spills, leaks, fire, exposure, or accidents involving this product. 3 / 10 Material name: Methyl mercaptan Solution Check for and remove any contact lenses. Methanethiol / ˈ m ɛ θ eɪ n ˈ θ aɪ ɒ l / (also known as methyl mercaptan) is an organosulfur compound with the chemical formula CH 3 SH.It is a colorless gas with a distinctive putrid smell. Exposure results in pulmonary edema and hepatic and renal damage. (EPA, 1998) METHYL MERCAPTAN is a reducing agent--can react vigorously with oxidizing agents. Dangerous fire or explosion hazard when exposed to heat, flame, sparks or strong oxidizing agents (e.g., calcium hypochlorite). Methyl Isopropyl Ketone (Com.) Hydrogen sulfide interferes with oxygen use in the body as well. It is a consolidation of the limits set out in the Table 1 in Regulation 833, also known as the ‘Ontario Table”, as well as applicable limits set out in the ACGIH publication, 2011 Threshold Limit Values and Biological Exposure Indices known as the “ACGIH Table” in Regulation 833. Quick navigation. Methyl mercaptan has been found in the environmental air at 4 ppb (4 parts of methyl mercaptan per billion parts of air). Levels of methyl mercaptan in soil are probably very low. Even at hazardous waste sites, the levels were about 83 ppb. Exposure Limits. combustible gas) and oxygen (air) must exist in certain proportions, along with an ignition source, such as a spark or flame. Exposure to large doses may cause central nervous system depression. Occupational exposure limits for hazardous agents in the workplace. Methyl mercaptan's low odor threshold of 0.00054 p.p.m. It is used as a gas odorant; an intermediate in the production of pesticides, jet fuels, and plastics; in the synthesis of methionine; and as a catalyst. While methyl mercaptan is strongly odorous, the low levels present in foods, human breath, sea air, and bogs are not considered safety risks. Most humans can detect methyl mercaptan odor at concentrations 500 times lower than the accepted safe exposure limit. At room temperature (above 43°F), methyl mercaptan is a colorless gas with an unpleasant odor described as rotten cabbage. Methyl Mercaptan (Compressed) Safety Data Sheet according to the Hazardous Products Regulation (February 11, 2015) ... exposure limits (where available). 77, No. 29 CFR § 1910.1000 - Air contaminants. OSHA PEL (permissible exposure limit) = 10 ppm (20 mg/m It is a natural substance found in the blood, brain and feces of animals (including humans), as well as in plant tissues.It also occurs naturally in certain foods, such as some nuts and cheese. An employee 's exposure to any substance listed in Tables Z-1, Z-2, or Z-3 of this section shall be limited in accordance with the requirements of the following paragraphs of this section . Skin: Wear appropriate protective gloves to … The lack of subchronic or chronic oral toxicity data for humans or animals precludes derivation of a subchronic or chronic p-RfD for methyl mercaptan. methyl mercaptan have central nervous system (CNS) effects. If methyl mercaptan is spilled or leaked, the following steps should be taken: 1. Methyl mercaptan is a naturally occurring colorless gas with a foul odor similar to rotten cabbage and decaying mattter (Agency for Toxic Substances and Disease Registry, 1992). A TLV-TWA of 0.5 ppm (1 mg/m 3) is recommended for occupational exposure to methyl mercaptan to minimize the potential for systemic effects. mercaptan, ethylenediamine, fluorides, hexane isomers, hydrogen sulfide, methyl ethyl ketone, methyl mercaptan, nitric acid, sulfuric acid, and toluene diisocyanate) remain on the list as TAPs. 8.2.2. Under the authority of the Federal Advisory Committee Act (FACA) P.L. MAK: 1.0 mg/m 3, 0.5 ppm; peak limitation category: II(2); pregnancy risk group: D Sensitization n-Dodecyl Methyl Sulfide : The product is a skin sensitizer, sub-category 1B. 1980 Anon. Methanethiol / ˈ m ɛ θ eɪ n ˈ θ aɪ ɒ l / (also known as methyl mercaptan) is an organosulfur compound with the chemical formula CH 3 SH.It is a colorless gas with a distinctive putrid smell. ); Methanethiol Methyl Mercaptan; Methanethiol Revised January 1995 74-93-1 UN 1064 (RQ I00/45.4) Division 2.3 CH3SH Aliphatic Mercapton Acute Exposure Guideline Levels for Selected Airborne Chemicals, Volume 15 identifies, reviews, and interprets relevant toxicologic and other scientific data for ethyl mercaptan, methyl mercaptan, phenyl mercaptan, tert-octyl mercaptan, lewisite, methyl isothiocyanate, and selected monoisocyanates in order to develop acute exposure guideline levels (AEGLs) for these … (APF = 25) Any powered, air-purifying respirator with organic vapor cartridge (s) Up to 25 ppm: (APF = 50) Any chemical cartridge respirator with a … for maintenance activities. Methyl isocyanate (MIC) is an organic compound with the molecular formula CH 3 NCO. (39) Tansy F. et al, Acute and subchronic toxicity studies of rats exposed to vapors of methyl mercaptan and other reduced sulfur compounds, J. Toxico. Acute Exposure Guideline Levels for Selected Airborne Chemicals, Volume 15 identifies, reviews, and interprets relevant toxicologic and other scientific data for ethyl mercaptan, methyl mercaptan, phenyl mercaptan, tert-octyl mercaptan, lewisite, methyl isothiocyanate, and selected monoisocyanates in order to develop acute exposure guideline levels (AEGLs) for these … Poisonous, flammable vapor is produced. for detection and reported irritation threshold of 1500 p.p.m. 92-463 of 1972, the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances (NAC/AEGL Committee) has been established to identify, review, and interpret relevant toxicologic and other scientific data and … The polyploidy effect in vitro may be due to a pH shift, since a 21% aqueous sodium methanethiolate solutionhasa pHof> 10. 58 / Monday, March 26, 2012 / Rules and Regulations 04/22/2015 EN (English US) SDS ID: 50006 / P/N 3471 4/1 SECTION 8: Exposure controls/personal protection 8.1. Methyl mercaptan is also released as a decay product of wood in pulp mills. PREFACE. Repeated or long-term exposure may damage the red blood cells causing anemia. OCCUPATIONAL EXPOSURE LIMITS; TLV: 0.5 ppm as TWA. Methyl mercaptan is a natural substance released from decaying matter. METHYL MERCAPTAN MMC CAUTIONARY RESPONSE INFORMATION Common Synonyms Liquefied compressed gas Colorless Strong garlic odor Floats and boils on water. Photodegradation in the air. 2 Methyl Mercaptan 1 Acute Exposure Guideline Levels. It is a natural substance found in the blood, brain and feces of animals (including humans), as well as in plant tissues.It also occurs naturally in certain foods, such as some nuts and cheese. Consider the potential hazards of this material (see Section 2), applicable exposure limits, job AVOID CONTACT WITH LIQUID AND VAPOR. Exposure Limits Personal Protective Equipment Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Exposure limit(s) NIOSH REL: C 0.5 ppm (1 mg/m3) [15-minute] OSHA PEL: C 10 ppm (20 mg/m3) IDLH 150 ppm: Poison_Class: 4: Exposure effects: May cause liver and kidney damage. Cyclohexanol is the organic compound with the formula HOCH(CH 2) 5.The molecule is related to cyclohexane by replacement of one hydrogen atom by a hydroxyl group. Not applicable (g as). Methyl mercaptan is on the EPA's list of regulated toxic substances, but there is a limited amount of toxicological data on methyl mercaptan; the LC 50 for rats by inhalation for 1 hour is 1.3 g/m 3, and the OSHA PEL is 19.7 mg/m 3 (BOC, 1996). Substance ... assessment indicates this is necessary to avoid exposure to liquid splashes, mists, gases or dusts. Exposure to large doses may cause central nervous system depression. Capsaicin and several related alkaloids are called capsaicinoids and are produced as secondary … Control parameters Methane with Methyl Mercaptan (Methanethiol) Health 4 Flammability 2 ... exposure limits are exceeded or if irritation or other symptoms are experienced. Product Use: Many. Up to 12.5 ppm: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely. No data regarding the toxicity of methyl mercaptan to animals following oral exposure were located. Chemsrc provides Methyl mercaptan(CAS#:74-93-1) MSDS, density, melting point, boiling point, structure, formula, molecular weight etc. Inhalation. follow mfr instructions, approx 50-1000 ppm range. 6 If the exposure limit in §1910.1026 is stayed or is otherwise not in effect, the exposure limit is a ceiling of 0.1 mg/m 3. The National Institute of Occupational Safety and Health (NIOSH) has set the Immediately Dangerous to Life and Health (IDLH) limits for methyl mercaptan at 150 ppm and the IDLH for hydrogen sulfide at 100 ppm. METHYL MERCAPTAN 20 PPM FOR 5 MINUTES METHYL METHACRYLATE 200 PPM FOR 15 MINUTES METHYL STYRENE 100 PPM FOR 30 MINUTES METHYLENE BIS PHENYLISOCYANATE 0.25 mg/m3 FOR 5 MINUTES ... Short Term Limits For Exposure To Airborne Contaminants, Pennsylvania Department of Health Mercaptomethane Methaneethiol Methyl sulfhydrate Thiomethyl alcohol KEEP PEOPLE AWAY. 2. Standards and Guidelines OSHA PEL (permissible exposure limit) = 10 ppm (20 mg/m 3 ) NIOSH REL (recommended exposure limit) = 0.5 ppm 2. It is generally shipped as a liquified compressed gas. Methyl mercaptan Methyl methacrylate Methyl oxirane 4-Methyl pentan-2-one 1-Methyl-prop-2-ene Methyl n-propyl ketone (MPK) Methyl salicylate ... concentration and their exposure limits per the UK OEL, NIOSH REL and ACGIH TLV. Find everything you wanted to know about compressed gases including hazard class, description and hazards, Hazard Control Plan, regulatory information, signs and symptoms of exposure, and more on the Toxic and Hazardous Gas Classifications Chart below or download the entire Toxic and Hazardous Gas … Exposure Control Measures/ Personal Protection Exposure Limits/Guidelines: Name CAS# Percent Agency Exposure Limits Comments Turpentine and Terpene Hydrocarbon Isomers 8006-64-2 97 – 99 OSHA ACGIH PEL-TWA 100 ppm TLV-TWA 20 ppm None Sensitizer Methyl mercaptan (CH 4 S) 74-93-1 0.2 – 2.5 OSHA ACGIH Ceiling (C) 10 ppm 29 CFR § 1910.1000 - Air contaminants. Before a fire or explosion can occur, three conditions must be met simultaneously. The site is secure. Therefore, no data are available, including the studies with sodium methanethiolate, which would support the 8. Control parameters Methane with Methyl Mercaptan (Methanethiol) 7 See Table Z-3 for the exposure limit for any operations or sectors where the exposure limit in § 1910.1053 is stayed or is otherwise not in effect. Natural Gas (Pipeline Quality) SAFETY DATA SHEET Date of Preparation: June 13, 2017 Page 5 of 10 Deerfoot Consulting Inc. PEL (permissible exposure limit) -The OSHA limits of employee exposure to chemicals; found primarily in 29 CFR 1910.1000, table Z-1. 4 tert-Octyl Mercaptan 1 Acute Exposure Guideline Levels. METHYL MERCAPTAN 20 PPM FOR 5 MINUTES METHYL METHACRYLATE 200 PPM FOR 15 MINUTES METHYL STYRENE 100 PPM FOR 30 MINUTES METHYLENE BIS PHENYLISOCYANATE 0.25 mg/m3 FOR 5 MINUTES ... Short Term Limits For Exposure To Airborne Contaminants, Pennsylvania Department of Health Lower and Upper Explosive Limits for Flammable Gases and Vapors. If methyl mercaptan is spilled or leaked, the following steps should be taken: 1. 77, No. 71H: 0.5-2 strokes, 2-2700 ppm range, uncertainty 16% for 50-200 ppm, 8% for 200-1000 ppm. Look for the ebook "Standing Operating Procedures For Developing Acute Exposure Guideline Levels For Hazardous Chemicals" Get it for FREE, select Download or Read Online after you press the "GET THIS EBOOK" button, There are many books available there. The CSB determined that the cause of the highly toxic methyl mercaptan release was the flawed engineering design and the lack of adequate safeguards.e Contributing to the severity of the incident were numerous safety Exposure controls Ingestion: Causes gastrointestinal irritation with nausea, vomiting and diarrhea. OSHA: 10 ppm (C), 20 mg/m³ (C); For Methyl mercaptan 0.5 ppm (TWA) [Vacated]; British Columbia: 0.5 ppm (TWA) PEL: Permissible Exposure Limit TWA: Time-Weighted Average. This compound exists as a deliquescent colorless solid with a camphor-like odor, which, when very pure, melts near room temperature. Ceiling is the maximum allowable concentration to which an employee may be exposed. Tables 1 and 2 of Annexure 1 list the occupational exposure limits, which should be used in determining the adequacy of control of exposure by inhalation, as required by the HCS Regulations. On this page you will be able to access individual Acute Exposure Guideline Level (AEGLs) values that are intended to protect most individuals in the general population, including those that might be particularly susceptible to the harmful effects of the chemicals. personal protective equipment The main toxic effect of exposure to Methyl Mercaptan is irritation of the respiratory airway, skin, and eyes. An LC. Based on the ACGIH recommendation, the Agency proposed revising this limit to an 8-hour TWA of 0.5 ppm, and OSHA is establishing this limit in the final rule. Under the authority of the Federal Advisory Committee Act (FACA) P. L. 92-463 of 1972, the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances (NAC/AEGL Committee) has been established to identify, review, and interpret relevant toxicologic and other scientific … (1) Substances with limits preceded by “C” - Ceiling Values. Both sodium methanethiolate and methyl mercaptan do not induce micronuclei in mice after oral or inhalation exposure. 8. Methyl Mercaptan 0.0001 - 0.05 74-93-1 Isopropyl alcohol 0.0001 - 0.05 67-63-0 n-Propyl Mercaptan 0.00001 - 0.05107-03-9 ... Occupational exposure limits, if available, are listed in Section 8. Most humans can detect methyl mercaptan odor at concentrations 500 times lower than the accepted safe exposure limit. Amoore and Hautala (1983) reported an odor threshold of 7.6 × 10-4 ppm for ethyl mercaptan. This value is the geometric mean calculated from reliable published odor threshold values. Nagata (2003) reported an odor threshold of 8.7 × 10-6 ppm for ethyl mercaptan. Gas detectors should be used when toxic gases may be released. Gas … Billions of kilograms are produced annually, mainly as a precursor to nylon. Quick navigation. Standing Operating Procedures For Developing Acute Exposure Guideline Levels For Hazardous Chemicals. In November 2014, a methyl mercaptan leak killed four workers at a DuPont chemical plant in La Porte, Texas. Part 1: Chemical hazardous agents. The following table is a complete listing of OELs applicable to Ontario workplaces. 77, No. Learn the hazard class of toxic and hazardous gases. 1981). Final AEGLs for Methyl mercaptan (74-93-1) Exposure Period AEGL-1 AEGL-2 AEGL-3; 10 minutes: NR: 40 ppm : 120 ppm : 30 minutes: NR: 29 ppm : 86 ppm : 60 minutes: NR: 23 ppm : 68 ppm : 4 hours: NR: 14 ppm : 43 ppm : 8 hours: NR: 7.3 ppm : 22 ppm Exposure controls/personal protection Occupational exposure limits The following constituents are the only constituents of the product which have a PEL, TLV or other recommended exposure limit. The genes from M. methylotropha strain TR3 encoding methanesulfonate monooxygenase, the enzyme responsible for the initial oxidation of MSA to formaldehyde and sulfite, were cloned and sequenced.They … Methyl Mercaptan Methyl mercaptan; Mercaptomethane; CH3SH; Methyl sulfhydrate; Methyl thioalcohol; ... Occupational exposure limits, if available, are listed in Section 8. Marinosulfonomonas methylotropha strain TR3 is a marine methylotroph that uses methanesulfonic acid (MSA) as a sole carbon and energy source. If methyl mercaptan is in the gaseous form, stop the flow of gas. A fuel (ie. 1907/2006 (R EACH) with its amendment Regulation (E C) No. While methyl mercaptan is strongly odorous, the low levels present in foods, human breath, sea air, and bogs are not considered safety risks. Individual protection measures, e.g. NIOSH: The recommended airborne exposure limit is 0.5 ppm, which should not be exceeded at any time. … 92-463 of 1972, the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous Substances (NAC/AEGL Committee) has been established to identify, review, and interpret relevant toxicologic and other scientific data and … PREFACE. The following list of North American Industrial Classification System (NAICS) codes is not intended to be exhaustive, but rather provides a guide … Users must be aware of exposure limit guidelines, such as TLV, for the target compound. Product Use: Many. Other information (1) Substances with limits preceded by “C” - Ceiling Values. An odour threshold of 0.002 ppm has been reported for methyl mercaptan, but olfactory fatigue may occur and thus, it may not provide adequate warning of hazardous concentrations. GASES - TOXIC - FLAMMABLE (Extreme Hazard) • DO NOT EXTINGUISH A LEAKING GAS FIRE UNLESS LEAK CAN BE STOPPED. It is slightly soluble in water. Methane with Methyl Mercaptan (Methanethiol) Safety Data Sheet according to Federal Register / Vol. Methane with Methyl Mercaptan (Methanethiol) Safety Data Sheet according to Federal Register / Vol. for maintenance activities. Articles of … METHYL MERCAPTAN MMC 9.20 SATURATED LIQUID DENSITY Temperature (degrees F) Pounds per cubic foot 0 5 10 15 20 25 30 35 40 57.730 57.490 57.250 57.010 56.760 56.520 56.280 Exposure to airborne dust at > ... - Mercaptans (including methyl mercaptan) - Dialkylsulfides (including dimethyl sulfide) - Thiophosphates - Oxides of hydrogen, nitrogen, sulfur, carbon and phosphorous. Methyl Mercaptan Ethyl Mercaptan Dimethyl Sulfide Carbon Disulfide Isopropyl Mercaptan tert-Butyl Mercaptan n-Propyl Mercaptan Methylethylsulfide 3 Of these, ammonia, hexane isomers, hydrogen sulfide, methyl mercaptan, and sulfuric acid were considered to be of higher priority for future review. Repeated dose toxicity n-Dodecyl Methyl Sulfide : Species: rat (male) Application Route: oral gavage Dose: 250, 500, 1000 mg/kg/d Exposure time: 35 d Number of exposures: daily NOEL: 1,000 mg/kg follow mfr instructions, approx 5-140 ppm range. Methyl mercaptan should be stored in cool, well ventilated places. Methyl mercaptan, a foul-smelling gas, overwhelmed five workers at the DuPont chemical plant in La Porte on Nov. 15, killing four – including two brothers – … Methyl mercaptan is a flammable, water-soluble gas with a disagreeable odor like that of rotten cabbage. Gas Detectors and Sensors Tubes Filters Masks and Filters. Chemsrc provides Methyl mercaptan(CAS#:74-93-1) MSDS, density, melting point, boiling point, structure, formula, molecular weight etc. methyl mercaptan (7 4-93-1) Persistence and degradability Readily biodegradable in water in anaerobic conditions. Component Name Synonyms Chemical Formula CAS Number Concentration (% Volume) Methane Methyl hydride, marsh gas, carbane CH4 74‐82‐8 90‐100 Find AEGL values in the table below using the chemical name or its CAS number. Phase II Critiqued Sources No A or B Codes DO m "oO Methyl Mercaptan Phase I Rejected/Unrevicwed Sources Methanethiol 3] Freudenberg 1955 Endo 1967 Hamanabe 1969 Bozza 1949 Guadagni 0.00011966 D Selyuzhitskii E1972 0.000 Blanchard 1976 Bedborough 1979 Anon. You may be potentially affected by this action if you are an agricultural producer, food manufacturer, or pesticide manufacturer. 74-93-1-1--137. Links with this icon indicate that you are leaving the CDC website.. (d) For the definition and the application of the Permissible Exposure Limit (PEL), refer to section 5155(b) and (c)(1). ACGIH: The recommended airborne exposure limit is 0.5 ppm averaged over an 8-hour workshift. Moreover, its odour can be described as that of rotten cabbage or garlic. Most humans can detect methyl mercaptan odor at concentrations 500 times lower than the accepted safe exposure limit. An odour threshold of 0.002 ppm has been reported for methyl mercaptan, but olfactory fatigue may occur and thus, it may not provide adequate warning of hazardous concentrations. § 1910.1000 Air contaminants. Ensure exposure is below occupational exposure limits (where available). FEASIBILITY OF DERIVING PROVISIONAL SUBCHRONIC AND CHRONIC ORAL RfDs FOR METHYL MERCAPTAN. If the source of the leak is a cylinder and the leak cannot be stopped in place, remove the leaking cylinder to a safe place in the open air and repair the leak or allow the cylinder to empty. * The above exposure limits are for air levels only. Methyl Mercaptan Standard Persistence and degradability Not established. Acute Exposure Guideline Levels for Selected Airborne Chemicals, Volume 15 identifies, reviews, and interprets relevant toxicologic and other scientific data for ethyl mercaptan, methyl mercaptan, phenyl mercaptan, tert-octyl mercaptan, lewisite, methyl isothiocyanate, and selected monoisocyanates in order to develop acute exposure guideline levels (AEGLs) for these …