Risk assessment residential

Three primary occupancy classifications are used in fire risk assessment residential, institutional and commercial. 

Fire risk assessment is made in order to determine the overall value of decreasing fire hazard in a particular scenario. The level of fire risk that is acceptable for a situation is, normally, a societal, and not a technical, decision. Therefore, fire hazard assessments are generally more common than fire risk assessments. The NFPA Research Foundation has undertaken a project to develop a methodology for fire risk assessment. It has done this by studying four cases in detail upholstered furniture in residential environments, wire and cable in concealed spaces in hotels and motels, floor coverings in offices and wall coverings in restaurants. 

The influence of physical habitat, pyrethroids, and metals on benthic community condition in an urban and residential stream in California. Hum Ecol Risk Assess, 15, 526-553. 

Action level for dioxin and dioxin-like compounds in soil. Action levels are concentrations of chemicals at which consideration of action to interdict exposure occurs 1 ppb TCDD in residential soil was identified by Kimbrough et al. (1984) as a "level of concern" and recommended as "a reasonable level to begin consideration of action to limit exposure." The conclusions of Kimbrough et al. (1984) were derived in part from an evaluation of the carcinogenic potential of TCDD, based on a 2-year oral chronic toxicity and oncogenicity study in rats (Kociba et al. 1978). With the advancement of knowledge about dioxin-like chemicals and their assumed common mechanism of toxicity, the TEQs were introduced into the risk assessment process. Since then, 1 ppb of total dioxins (expressed as TEQs) in soil has been used as an action level by ATSDR. 

Quantitative risk assessments have been performed on a variety of flame-retardants used both in upholstered furniture fabric and foam. The National Research Council performed a quantitative risk assessment on 16 chemicals (or chemical classes) identified by the U.S. Consumer Product Safety Commission (CPSC). The results were published in 2000.88 The 16 flame-retardants included in this NRC study were HBCD, deca-BDE, alumina trihydrate, magnesium hydroxide, zinc borate, calcium and zinc molybdates, antimony trioxide, antimony pentoxide and sodium antimonate, ammonium polyphosphates, phosphonic acid, (3- [hydroxymethyl]amino -3-oxopropyl)-dimethylester, organic phosphonates, tris (monochloropropyl) phosphate, tris (l,3-dichloropropyl-2) phosphate, aromatic phosphate plasticisers, tetrakis (hydroxymethyl) hydronium salts, and chlorinated paraffins. The conclusions of the assessment was that the following flame-retardants can be used on residential furniture with minimal risk, even under worst-case assumptions ... 

The CPSC staff performed quantitative risk assessments on various flame-retardants for both upholstered residential furniture fabrics and foam.89 CPSC addresses chemical hazards under the Federal Hazardous Substances Act (FHSA), which is risk based. For fabrics, five flame-retardants were evaluated, that include antimony trioxide, deca-BDE, HBCD, phosphonic acid, (3- [hydroxymethyl]amino)-3-oxopropyl)-, dimethyl ester (PA), and tetrakis (hydroxymethyl) phosphonium chloride (THPC). These flame-retardants were selected for study because they are used to comply with the U.K. upholstered furniture flammability standard (except THPC) and fabric samples were available for testing. The staff concluded in 2006 that deca-BDE, HBCD, and PA would not present a hazard to consumers and that additional data would be needed to assess antimony trioxide and THPC. 

The following is a brief description of the use of the Hydrogen Risk Assessment Method (HRAM) to analyze the risk associated with hydrogen leakage in a residential garage. The four-step method is as follows ... 

If the estimated level of exposure is less than the reference dose (RfD), the pesticide is considered to be safe to use. The aggregation (addition) of the amount of exposnre received from each source will increase the total exposure to a level which may then exceed the RfD. In addition to aggregation increasing the level of exposure, the reference dose is becoming smaller because of the use of extra safety factors to protect children. The trend towards lower reference doses impacts both residential and worker risk assessments. 

The need for aggregate and cumulative non-occupational exposure assessments, and lower reference doses for all assessments, means that some pesticides will fail lower-tier risk assessments and without more refined exposure data they might even fail higher-tiered assessments. For example, in North America many of the residential uses of the OPs have been discontinued as a result of the aggregate risk assessments. As a result, there has been increased emphasis on gathering better toxicology and exposure data to reduce the conservatisms that are contained in the current system. 

Residential risk assessment to pesticides typically involves more than one sonrce and mnitiple pathways and rontes, e.g. a given active ingredient may be nsed for multiple indoor apphcations, and in some cases, for outdoor applications. In some cases, the applications may overlap with respect to timing (calendar days). The potential co-occurrence of applications and potential exposures requires temporal product use information. Such information is rarely available. 

Because data on non-professional exposure is scarce but exposure assessments are necessary, models have become a main tool in assessing residential exposure. It appears to be easier to obtain good quality data on exposure factors (room sizes, typical amounts used, etc.), which can be used as parameters in models, than to obtain direct exposure measurements. Critics of the modeling process say that the information generated through models is suspect because of the inherent simplifications involved. This criticism may be valid if risk assessors who utilize models do not make the appropriate selections that are needed in their application. They need to ask the following which model should be used which data should be fed into the model why do these two (three) models produce different results, and are the differences significant for risk assessment which data are necessary... 

In this present chapter, the role that models can play in the risk assessment of pesticides used in the residential setting and the currently available models are described. In particular, the ways in which residential exposnre models are constructed, validated and used are explored. 

The SCIES and MCCEM models give only inhalation exposure, but the simulated results can be incorporated into a whole-risk assessment in the residential space such as the USEPA SOP framework (USEPA, 1997b) which estimates multiple exposure levels via all routes (i.e. inhalation, dermal and oral). THERdbASE is capable of estimating inhalation and dermal exposures based on the simulated airborne concentration and the film-thickness theory, and InPest estimates all exposures, including oral routes, based on the simulated concentration in the air and amounts on the room materials (Matoba et al., 1998c). 

Residential exposure should be estimated by taking into account distributions of exposure factors. Methods to assess distributions are through the deterministic or probabilistic approach (Figure 6.6). The former is often taken in preventive risk assessment in which each default value is determined from each distribution as a reasonable worst-case . The estimated exposures for the deterministic approach are expected to occur in the upper range. For actual risk assessments, the probabilistic approach directly uses the parameter distributions instead of single values to calculate distributions of exposure. To characterize exposure, an... 

Probabilistic risk assessment methods are used to incorporate uncertainty and variability into both aggregate and cumulative risk assessments. Herein, uncertainty refers to lack of knowledge or the limitations in the current state of knowledge. For example, the dermal permeability of a pesticide may not be known with certainty. Variability, on the other hand, refers to a value that differs from one individual to another individual in a population or from one instance to another. For example, the number of apphcations of a residential pesticide in a year may vary from one individual to another. Probabilistic methods use probability distributions to incorporate uncertainty and variability into both aggregate and cumulative risk assessments. 

OCCUPATIONAL AND RESIDENTIAL RISK ASSESSMENT 371 AOELs Versus MOEs 371 Route Considerations 372 Uncertainty and Safety Factor Selection 372 Aggregation and Cumulative Risk Assessment 372 CO-OPERATIVE REGULATORY ACTIVITIES 373 SUMMARY AND CONCLUSIONS 374 Terminology 374 Framework 374 Data Requirements 374 Methodological Guidance 375 Development and Utility of Databases 375 Modeling Initiatives 375 Data Analysis 375 Metric Selection 376 Research Needs 376 Exposure Mitigation 376 Risk Assessment 376 REFERENCES 376... 

Canada has generated time-weighted average exposures for occupational and residential post-application exposnre scenarios where dislodgeable (transferable) foliar residue data have yielded dissipation curves which allow generation of daily exposure estimates on snccessive days following apphcation. These estimates have potential utility in risk assessments not based on acute toxicological endpoints. 

In North America, similar approaches are used in the condnct of occupational and residential risk-assessment approaches. AOELs, per se, are not developed. Rather, appropriate toxicology endpoints are compared with exposure estimates and the resulting Margins of Exposure (MOEs) are compared with target margins of exposure. 

Agreement on the role of toxicology triggers, if any, in the tiered approach to occnpational and residential exposure and risk assessment. 

Development of a harmonized research strategy designed to inform occupational and residential exposure and risk assessments for pesticides. 

To ensure that chemical contamination is rednced to safe concentrations at stockpile and NSCM sites before they are used for residential, occupational, or wildlife purposes, the U.S. Army requested that health-based exposure limits for GA, GB, GD, VX, sulfur mustard, and lewisite be developed to protect the pnblic and the environment. Oak Ridge National Laboratory (ORNL) was asked to conduct the health risk assessments and propose chronic oral reference doses (RfDs) and, where... 

Exposure to indoor hydrocarbon vapors can occur as a consequence of changes of land use from commercial or industrial to residential. Residual hydrocarbons in soils or groundwater may result in a chronic vapor exposure pathway. Analysis of risk associated with exposure to hydrocarbons typically is undertaken in a multi-step approach known as risk assessment. A thorough discussion of the use of risk assessment at contaminated sites is provided in Chapter 9.01. Assessing risks posed by hydrocarbon spills or wastes is complex and involves estimates of chemical concentrations at each potential exposure point, identification of the potential populations that may be exposed, and assessment of exposure pathways, intake rates, and the toxicity of the chemicals of concern. 

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