Chemicals exposure Limits

Periodic maintenance, recoating Service conditions temperature limits, chemical exposure limits Repair procedures... 

Some of the model 5(e) orders have provisions for new chemical exposure limits, (NCELs) that can be implemented instead of using respirators to limit risks from inhalation of the PMN substance. NCELs are specific numerical limits on the airborne concentrations of the PMN substance. The EPA may develop a maximum concentration for eight hour exposures, a maximum concentration for work shifts that are shorter or longer than eight hours, and a short term exposure limit (STEL) for fifteen minute exposure periods. In order to use NCELs instead of respirators, the signatory must develop a sampling and analytical plan and have it verified by an independent third party laboratory. As of 2002 the EPA had developed thirty four NCELs. ... 

Recommend exposure limit— A NIOSH chemical exposure limit recommendation. 

New chemical exposure limits (NCELs) for new chemicals regulated under TSCA are modeled after OSHA s permissible exposure limits (PELs) for workers exposed to a substance by inhalation. NCELs may include an eight-hour time weighted average limit or a short-term exposure limit for a chemical substance. In 1995, the US EPA described the risk basis for determining... 

US EPA. 1995. Response to External Comments on New Chemical Exposure Limits... 

Applicable specific safety standards for workspace chemical exposure limits and/or concentrations which should be observed during the inspection, if any ... 

As another example, let s use chemical exposure limits. OSHA uses a PEL (permissible exposure level) of 1 ppm (part per million). A company might find it advantageous to choose a level of less than 1 ppm to ensure that exposure levels stay low. Taking a stance that is more stringent than current government standard levels provides companies (and workers) with an extra level of confidence that workers will not be injured or have their health adversely affected by exposure. 

Chemical Exposure Limit List list of some common chemicals stored and used within the XYZ s Central Environmental Laboratory (CEL). The permissible exposure limit (PEL), threshold limit value (TLV), and immediately dangerous to life and health limit (IDLHL) are listed where applicable. 

Safety. Magnesium oxide (fume) has a permissible exposure limit (PEL) (134) (8 hours, TWA), of 10 mg/m total dust and 5 mg/m respirable fraction. Tumorigenic data (intravenous in hamsters) show a TD q of 480 mg/kg after 30 weeks of intermittent dosing (135), and toxicity effects data show a TC q of 400 mg/m for inhalation in humans (136). Magnesium oxide is compatible with most chemicals exceptions are strong acids, bromine pentafluoride, chlorine trifluoride, interhalogens, strong oxidizers, and phosphorous pentachloride. 

Appropriate protective clothing and equipment should be worn to minimize exposure to methacrylate liquids and vapors. Chemically resistant clothes and gloves and splash-proof safety goggles ate recommended. The working area should be adequately ventilated to limit vapors. Should chemical exposure occur, contaminated clothing should be removed and the affected area washed with copious amounts of water. Medical attention should be sought if symptoms appear. Eurther information about methyl methacrylate and other methacrylates is available (141). 

It is good practice to keep concentrations of airborne nickel in any chemical form as low as possible and certainly below the relevant standard. Local exhaust ventilation is the preferred method, particularly for powders, but personal respirator protection may be employed where necessary. In the United States, the Occupational Safety and Health Administration (OSHA) personal exposure limit (PEL) for all forms of nickel except nickel carbonyl is 1 mg/m. The ACGIH TLVs are respectively 1 mg/m for Ni metal, insoluble compounds, and fume and dust from nickel sulfide roasting, and 0.1 mg/m for soluble nickel compounds. The ACGIH is considering whether to lower the TLVs for all forms of nickel to 0.05 mg/m, based on nonmalignant respiratory effects in experimental animals. 

The National Institute of Occupational Safety and Health (NIOSH), under the Department of Health and Human Services, works with OSHA. It is NIOSH s responsibihty to determine safe exposure limits for chemical substances and to recommend to OSHA that these limits be adopted as standards. 

Styrene is Hsted in the U.S. Toxic Substance Control Act (TSCA) Inventory of Chemicals. It is not confirmed as a carcinogen but is considered a suspect carcinogen. The recommended exposure limits are OSHA PEL 50 ppm, ACGIH TLV 50 ppm. For higher concentrations,... 

Thiophene and 3-methylthiophene are Hsted on the TSCA chemical substances inventory. Thiophene is regulated as a hazardous material under OSHA and also regulated under the Clean Air Act, Section 110, 40 CFR 60.489, but there are no exposure limits or controls set for 3-methylthiophene. Both materials are regulated under sections 311/312 of the Superfund Amendments and Reauthorization Act, 1986 (SARA), as materials with an acute health and fire hazard, and under the Resource Conservation and Recovery Act, as ignitable hazardous wastes (DOOl). 

Safety. Chlorosulfuric acid is a strong acid and the principal ha2ard is severe chemical bums when the acid comes into contact with body tissue. The vapor is also ha2ardous and extremely irritating to the skin, eyes, nose, and respiratory tract. Exposure limits for chlorosulfuric acid have not been estabhshed by OSHA or ACGIH. However, chlorosulfuric acid fumes react readily with moisture in the air to form hydrochloric and sulfuric acid mists, which do have estabhshed limits. The OSHA 8-h TWA limits and ACGIH TLV—TWA limits are sulfuric acid = 1 mg/m hydrochloric acid = 5 ppm or 7 mg/m (ceiling limit). 

One early program carried out at AUied-Signal, Inc. proposed the use of conductive polymers in remotely readable indicators (210). Conductivity changes induced in the conductive polymer could be read externally and the history of the sample known. Systems designed to detect time—temperature, temperature limit, radiation dosage, mechanical abuse, and chemical exposure were developed. 

Cement and Concrete Concrete is an aggregate of inert reinforcing particles in an amorphous matrix of hardened cement paste. Concrete made of portland cement has limited resistance to acids and bases and will fail mechanically following absorption of crystalforming solutions such as brines and various organics. Concretes made of corrosion-resistant cements (such as calcium aluminate) can be selected for specific chemical exposures. 

Information pertaining to the hazards of the chemicals used in the process. This should contain at least the following information toxicity, flammability, permissible exposure limits, physical data, reactivity data, corrosivity data, thermal and chemical stability data, and hazardous effects of inadvertent mixing of different materials that could occur. 

The toxicity of a substance is its capacity to cause injury once inside the body. The main modes of entry into the body by chemicals in industry are inhalation, ingestion and absorption through the skin. Gases, vapours, mists, dusts, fumes and aerosols can be inhaled and they can also affect the skin, eyes and mucous membranes. Ingestion is rare although possible as a result of poor personal hygiene, subconscious hand-to-mouth contact, or accidents. The skin can be affected directly by contact with the chemicals, even when intact, but its permeability to certain substances also offers a route into the body. Chemicals accorded a skin notation in the list of Occupational Exposure Limits (see Table 5.12) are listed in Table 5.2. Exposure may also arise via skin lesions. 

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