Rankine Temperature (Thermodynamic English System)
R & D
Research and Development
RA
Risk Assessment
RAD
Radiation Absorbed Dose. The RAD is a basic unit of absorbed radiation dose. The RAD ia being replaced by the “gray”, which is equivalent to 100 RADs. RAD = 100 ergs/1 gram material.
RACM
Reasonable Available Control Measure
RACT
Reasonable Available Control Technology: (CAA 40 CFR Part 0 – 52, 60). Applied to existing sources to meet NAAQS. Control equipment reasonably available and economically feasible to achieve the lowest emission limit applicable to a given source. RACT is required on existing sources in areas that are not meeting national ambient air quality standards (i.e., non-attainment areas).
Radioactive
decay
The process in which a radioactive nucleus emits (gives off) radiation and changes to a different isotope or element. A number of different particles can be emitted by decay. The most typical are alpha or beta particles.
RAM
Radioactive Material
RAS
Routine Analytical Service
RBCA
Risked-Based Corrective Action: A standardized approach to designing remediation strategies for contaminated sites, which reduces misallocation of resources and imposition of unreasonable generic remedies at sites posing little threat to human health or environment.
RCRA
Resource Conservation & Recovery Act (1976); regulates management and disposal of hazardous materials and wastes currently being generated, treated, recycled, stored or disposed.
RD/RA
Remedial Design/Remedial Action
RDX
Hexahydro-1,3,5-trinitro-1,3,5 trinitrotoluene (an explosive)
RED
Registration Eligibility Document
Reformulated gasoline
Specially refined gasoline with low levels of smog-forming volatile organic compounds (VOCs) and low levels of hazardous air pollutants. The 1990 Clean Air Act requires sale of reformulated gasoline in the nine smoggiest areas.
REL
Respirator Exposure Limit
REM
Roentgen Equivalent Man; unit of absorbed radiation dose. The REM takes into account the relative effectiveness of the radiation involved in causing health effects. The equation for determining radiation dosage is: radiation multiplied by a qualifying factor, such as duration or intensity of exposure. Small doses are measured in millirem; one REM = 1,000 millirem. Other countries, as well as the scientific community in the US , measure radiation dose in units called sieverts; one sievert = 100 REM.
RFA/RFI
RCRA Facility Assessment/RCRA Facility Investigation
RfD
Reference Dose: An estimate of the daily dose of a noncarcinogenic substance that will result in no adverse effect during a lifetime of exposure. EPA calculates RfDs by assuming that a 70-kilogram (154-pound) person ingests two liters of contaminated drinking water per day.
RHA
Rivers and Harbors Act
RI
Remedial Investigation
RI/FS
Remedial Investigation/Feasibility Study; an investigation at a hazardous waste site to assess contamination, health and environmental risks and cleanup alternatives.
Risk
The probability of injury, disease or death under specific circumstances
RMCL
Recommended Maximum Contaminant Level (SDWA; “Secondary” Drinking Water Standards)
RMP
Risk Management Plan (CAAA; Title III)
RO
Reverse Osmosis
ROD
Record of Decision; officially designated remedy chosen by EPA (CERCLA) for remediation of an NPL site.
RPAR
Rebuttal Presumption Against Registration (a response to suspension)
RPCC
Release Prevention, Control and Countermeasure
RPD
Relative Percent Difference
RQ
Reportable Quantity
RSD
The daily dose of a carcinogen that over a lifetime will result in an incidence of cancer equal to a specific risk level. The rish level used for a chronic toxicity reference level is 1E+5 (i.e., the probability that one person in 100,000 will contract some form of cancer in their lifetime due to exposure of the compound).
RSPA
Research and Special Programs Administration of DOT; branch of DOT that encompasses safety regulations, emergency preparedness and research and development associated with the transportation of hazardous materials.
RTECS
Registry of Toxic Effects of Chemical Substances: A substance’s identification number on the US Registry of Toxic Effects of Chemical Substances, a database compiled, maintained and updated by the National Institute for Occupational Safety and Health (NIOSH).
RUST
RCRA Underground Storage Tank
RVP
Reid Vapor Pressure
RWH
Reputable Waste Handlers