Exposure levels program

Exposure Levels in Humans. Although some data on the levels of americium in human tissues exposed to natural background levels (food, water, and air) are available, few measurements have been made on the americium content in human tissues. The principal source of information about occupationally exposed individuals is the U.S. Transuranium and Uranium Registries (USTUR) Tissue Program and database, established to document levels and distribution of uranium and transuranium isotopes in human tissues for occupationally exposed workers (USTUR 1999). Several major database files are available. 

Schalch, W. and F. M. Barker (2005). Ocular and general safety of supplementation with zeaxanthin and lutein plasma exposure levels of carotenoids and 3 -dehydro-lutein—Results of the LUXEA study. ARVO 2005 Abstract Book on CDROM Program 1765. 

Important commercial isocyanates include the diisocyanate monomers toluene diisocyanate (TDI), methylene diphenyl diisocyanate (MDI), hexamethylene diisocyanate (HDI), and MDI-, TDI-, and HDI-based isocyanates (e.g., prepolymers and polyisocyanates). World-wide production volume is estimated at over 12 billion lb. Isocyanates (diisocyanates, polyisocyanates, and prepolymers) all cause similar health effects, most commonly asthma [32]. Isocyanates are reported to be the leading attributable cause of work-related asthma [16]. Isocyanates are potent sensitizers that can trigger a severe and potentially fatal asthma attack in sensitized persons at very low isocyanate exposure levels [16]. Toluene diisocyanate is reasonably anticipated to be a human carcinogen by National Toxicology Program. 

The training program also includes a provision for timely feedback of new measurements of exposure levels, with additional control information where needed. 

RELs). The Air Toxics Hot Spots Program Risk Assessment Guidelines, Part 1 The Determination of Acute Reference Exposure Levels for Airborne Toxicants, March 1999 and the Air Toxics Hot Spots Program Risk Assessment Guidelines, Part III The Determination of Chronic Reference Exposure Levels for Airborne Toxicants, www.oehha.ca.gov/air/allrels.html (accessed 11 May 2009). 

In 1985, the EPA concluded that the benefits of CCA-treated wood far outweighed any risks. The EPA estabhshed modest use precautions, which the treating industry agreed to disseminate in a voluntary consumer-awareness program. The actual exposure levels to arsenic in CCA are considered to be minuscule. In 1990, the Consumer Product Safety Commission (CPSC) measured dislodgeable arsenic in eight samples of CCA-treated wood. In five of the samples, the amount was undetectable. 

Chronic exposure to dioxins has resulted in splenic and testicular atrophy, elevated gamma-glutamyl transpeptidase levels, elevated cholesterol levels, and abnormal neurologic findings. Additional effects include enzyme induction, diabetes, and endocrine changes. The chronic, noncancer reference exposure level of 3.5 xl0 pgm is listed for TCDD or 2,3,7,8-equivalents by the California Air Pollution Control Officers Association Air Toxics Hot Spots Program. 

OSHA requires employers of workers who are occupationally exposed to 2-butoxyethanol to institute engineering controls and work practices to reduce employee exposure and maintain it at or below pennissible exposure limits (PEL). The PEL for 2-butoxyethanol is 50 ppm (OSHA 1974). Workers exposed to 2-butoxyethanol should wear personal protective equipment such as gloves, coveralls, and goggles to protect exposure to tire skin (OSHA 1974). NIOSH recommends that industrial hygiene surveys be completed at work places where airborne exposure to 2-butoxyethanol or 2-butoxyethanol acetate may occur (NIOSH 1990). If exposure levels are at or above one-half the recommended exposure limit (REL = 5 ppm), NIOSH recommends that a program of personal monitoring be instituted so that tlie exposure of each worker can be estimated. If exposure levels are at or greater than the REL, or if there is a potential for skin contact, NIOSH recommends that 2-butoxyacetic acid be measured in the urine of the workers. 

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