ATSDR - Minimal Risk Levels for Hazardous Substances (MRLs)

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) [42 U.S.C. 9604 et seq.], as amended by the Superfund Amendments and Reauthorization Act (SARA) [Pub. L. 99-499], requires that the Agency for Toxic Substances and Disease Registry (ATSDR) develop jointly with the U.S. Environmental Protection Agency (EPA), in order of priority, a list of hazardous substances most commonly found at facilities on the CERCLA National Priorities List (NPL) (42 U.S.C. 9604(i)(2)); prepare toxicological profiles for each substance included on the priority list of hazardous substances, and to ascertain significant human exposure levels (SHELs) for hazardous substances in the environment, and the associated acute, subacute, and chronic health effects (42 U.S.C. 9604(i)(3)); and assure the initiation of a research program to fill identified data needs associated with the substances (42 U.S.C. 9604(i)(5)).

The ATSDR Minimal Risk Levels (MRLs) were developed as an initial response to the mandate. Following discussions with scientists within the Department of Health and Human Services (HHS) and the EPA, ATSDR chose to adopt a practice similar to that of the EPA's Reference Dose (RfD) and Reference Concentration (RfC) for deriving substance-specific health guidance levels for non-neoplastic endpoints. An MRL is an estimate of the daily human exposure to a hazardous substance that is likely to be without appreciable risk of adverse noncancer health effects over a specified duration of exposure. These substance-specific estimates, which are intended to serve as screening levels, are used by ATSDR health assessors and other responders to identify contaminants and potential health effects that may be of concern at hazardous waste sites. It is important to note that MRLs are not intended to define clean-up or action levels for ATSDR or other Agencies.

The toxicological profiles include an examination, summary, and interpretation of available toxicological information and epidemiologic evaluations of a hazardous substance. During the development of toxicological profiles, MRLs are derived when ATSDR determines that reliable and sufficient data exist to identify the target organ(s) of effect or the most sensitive health effect(s) for a specific duration for a given route of exposure to the substance. MRLs are based on noncancer health effects only and are not based on a consideration of cancer effects. Inhalation MRLs are exposure concentrations expressed in units of parts per million (ppm) for gases and volatiles, or milligrams per cubic meter (mg/m³) for particles. Oral MRLs are expressed as daily human doses in units of milligrams per kilogram per day (mg/kg/day). Radiation MRLs are expressed as external exposures in units of millisieverts.

ATSDR uses the no-observed-adverse-effect-level/uncertainty factor (NOAEL/UF) approach to derive MRLs for hazardous substances. They are set below levels that, based on current information, might cause adverse health effects in the people most sensitive to such substance-induced effects. MRLs are derived for acute (1-14 days), intermediate (>14-364 days), and chronic (365 days and longer) exposure durations, and for the oral and inhalation routes of exposure. Currently MRLs for the dermal route of exposure are not derived because ATSDR has not yet identified a method suitable for this route of exposure. MRLs are generally based on the most sensitive substance-induced end point considered to be of relevance to humans. ATSDR does not use serious health effects (such as irreparable damage to the liver or kidneys, or birth defects) as a basis for establishing MRLs. Exposure to a level above the MRL does not mean that adverse health effects will occur.

MRLs are intended to serve as a screening tool to help public health professionals decide where to look more closely. They may also be viewed as a mechanism to identify those hazardous waste sites that are not expected to cause adverse health effects. Most MRLs contain some degree of uncertainty because of the lack of precise toxicological information on the people who might be most sensitive (e.g., infants, elderly, and nutritionally or immunologically compromised) to effects of hazardous substances. ATSDR uses a conservative (i.e., protective) approach to address these uncertainties consistent with the public health principle of prevention. Although human data are preferred, MRLs often must be based on animal studies because relevant human studies are lacking. In the absence of evidence to the contrary, ATSDR assumes that humans are more sensitive than animals to the effects of hazardous substances that certain persons may be particularly sensitive. Thus the resulting MRL may be as much as a hundredfold below levels shown to be nontoxic in laboratory animals. When adequate information is available, physiologically based pharmacokinetic (PBPK) modeling and benchmark dose (BMD) modeling have also been used as an adjunct to the NOAEL/UF approach in deriving MRLs.

Proposed MRLs undergo a rigorous review process. They are reviewed by the Health Effects/MRL Workgroup within the Division of Toxicology; and expert panel of external peer reviewers; the agency wide MRL Workgroup, with participation from other federal agencies, including EPA; and are submitted for public comment through the toxicological profile public comment period. Each MRL is subject to change as new information becomes available concomitant with updating the toxicological profile of the substance. MRLs in the most recent toxicological profiles supersede previously published levels. To date, 122 inhalation MRLs, 198 oral MRLs and 6 external radiation MRLs have been derived. A listing of the current published MRLs by route and duration of exposure is provided as follows.

ATSDR Contact Person for MRLs:

Dr. Selene Chou
Division of Toxicology
Agency for Toxic Substances and Disease Registry
1600 Clifton Road, Mailstop F32
Atlanta, Georgia 30333
Telephone: 770-488-3357
E-Mail: cjc3@cdc.gov

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                                                    ATSDR MINIMAL RISK LEVELS (MRLs)                              
								January 2004             


                                          Dura-                     Fac-             Draft/ Cover
Name                                Route tion   MRL                tors   Endpoint  Final  Date   CAS Number
___________________________________________________________________________________________________________________

ACENAPHTHENE                        Oral  Int.   0.6 mg/kg/day        300  Hepatic   Final  08/95  000083-32-9

ACETONE                             Inh.  Acute  26 ppm                 9  Neurol.   Final  05/94  000067-64-1
                                          Int.   13 ppm               100  Neurol.
                                          Chr.   13 ppm               100  Neurol.
                                    Oral  Int.   2 mg/kg/day          100  Hemato.

ACROLEIN                            Inh.  Acute  0.00005 ppm          100  Ocular    Final  12/90  000107-02-8
                                          Int.   0.000009 ppm        1000  Resp.
                                    Oral  Chr.   0.0005 mg/kg/day     100  Hemato.

ACRYLONITRILE                       Inh.  Acute  0.1 ppm               10  Neurol.   Final  12/90  000107-13-1
                                    Oral  Acute  0.1 mg/kg/day        100  Develop.
                                          Int.   0.01 mg/kg/day      1000  Repro.
                                          Chr.   0.04 mg/kg/day       100  Hemato.

ALDRIN                              Oral  Acute  0.002 mg/kg/day     1000  Develop.  Final  09/02  000309-00-2
                                          Chr.   0.00003 mg/kg/day   1000  Hepatic

ALUMINUM                            Oral  Int.   2.0 mg/kg/day         30  Neurol.   Final  07/99  007429-90-5

AMMONIA                             Inh.  Acute  1.7 ppm               30  Resp.     Draft  09/02  007664-41-7
                                          Chr.   0.3 ppm               10  Resp.
                                    Oral  Int.   0.3 mg/kg/day        100  Other

ANTHRACENE                          Oral  Int.   10 mg/kg/day         100  Hepatic   Final  08/95  000120-12-7

ARSENIC                 Provisional Oral  Acute  0.005 mg/kg/day       10  Gastro.   Final  09/00  007440-38-2
                                          Chr.   0.0003 mg/kg/day       3  Dermal

ATRAZINE                            Oral  Acute  0.01 mg/kg/day       100  Body Wt.  Final  09/03  001912-24-9
                                          Int.   0.003 mg/kg/day      300  Repro.   

BENZENE                             Inh.  Acute  0.05 ppm             300  Immuno.   Final  09/97  000071-43-2
                                          Int.   0.004 ppm             90  Neurol.

BERYLLIUM                           Oral  Chr.   0.002 mg/kg/day      300  Gastro.   Final  09/02  007440-41-7

BIS(CHLOROMETHYL) ETHER             Inh.  Int.   0.0003 ppm           100  Resp.     Final  12/89  000542-88-1

BIS(2-CHLOROETHYL) ETHER            Inh.  Int.   0.02 ppm            1000  Body Wt.  Final  12/89  000111-44-4

BORON                               Oral  Int.   0.01 mg/kg/day      1000  Develop.  Final  07/92  007440-42-8

BROMODICHLOROMETHANE                Oral  Acute  0.04 mg/kg/day      1000  Hepatic   Final  12/89  000075-27-4
                                          Chr.   0.02 mg/kg/day      1000  Renal

BROMOFORM                           Oral  Acute  0.7 mg/kg/day        100  Hepatic   Draft  09/03  000075-25-2
                                          Int.   0.2 mg/kg/day        300  Hepatic
                                          Chr.   0.2 mg/kg/day        100  Hepatic

BROMOMETHANE                        Inh.  Acute  0.05 ppm             100  Neurol.   Final  09/92  000074-83-9
                                          Int.   0.05 ppm             100  Neurol.
                                          Chr.   0.005 ppm            100  Neurol.
                                    Oral  Int.   0.003 mg/kg/day      100  Gastro.

CADMIUM                             Oral  Chr.   0.0002 mg/kg/day      10  Renal     Final  07/99  007440-43-9

CARBON DISULFIDE                    Inh.  Chr.   0.3 ppm               30  Neurol.   Final  08/96  000075-15-0
                                    Oral  Acute  0.01 mg/kg/day       300  Hepatic

CARBON TETRACHLORIDE                Inh.  Int.   0.03 ppm              30  Hepatic   Draft  09/03  000056-23-5
                                          Chr.   0.03 ppm              30  Hepatic
                                    Oral  Acute  0.05 mg/kg/day        90  Hepatic
                                          Int.   0.02 mg/kg/day        30  Hepatic

CESIUM                              Rad.  Acute  4 mSv                  3  Develop.  Draft  07/01  007440-46-2
                                          Chr.   1 mSv/yr               3  Other

CHLORDANE                           Inh.  Int.   0.0002 mg/m³         100  Hepatic   Final  05/94  000057-74-9
                                          Chr.   0.00002 mg/m³       1000  Hepatic
                                    Oral  Acute  0.001 mg/kg/day     1000  Develop.
                                          Int.   0.0006 mg/kg/day     100  Hepatic
                                          Chr.   0.0006 mg/kg/day     100  Hepatic

CHLORDECONE                         Oral  Acute  0.01 mg/kg/day       100  Neurol.   Final  08/95  000143-50-0
                                          Int.   0.0005 mg/kg/day     100  Renal
                                          Chr.   0.0005 mg/kg/day     100  Renal

CHLORFENVINPHOS                     Oral  Acute  0.002 mg/kg/day     1000  Neurol.   Final  09/97  000470-90-6
                                          Int.   0.002 mg/kg/day     1000  Immuno.
                                          Chr.   0.0007 mg/kg/day    1000  Neurol.

CHLORINE DIOXIDE                    Inh.  Int.   0.001 ppm            300  Resp.     Draft  09/02 010049-040-4

CHLORITE                            Oral  Int.   0.1 mg/kg/day         30  Neurol    Draft  09/02 007758-19-2

CHLOROBENZENE                       Oral  Int.   0.4 mg/kg/day        100  Hepatic   Final  12/90  000108-90-7

CHLORODIBROMOMETHANE                Oral  Acute  0.1 mg/kg/day        300  Renal     Draft  09/03  000124-48-1
                                          Chr.   0.09 mg/kg/day       300  Hepatic

CHLOROETHANE                        Inh.  Acute  15 ppm               100  Develop.  Final  12/98  000075-00-3

CHLOROFORM                          Inh.  Acute  0.1 ppm               30  Hepatic   Final  09/97  000067-66-3
                                          Int.   0.05 ppm             100  Hepatic
                                          Chr.   0.02 ppm             100  Hepatic
                                    Oral  Acute  0.3 mg/kg/day        100  Hepatic
                                          Int.   0.1 mg/kg/day        100  Hepatic
                                          Chr.   0.01 mg/kg/day      1000  Hepatic

CHLOROMETHANE                       Inh.  Acute  0.5 ppm              100  Neurol.   Final  12/98  000074-87-3
                                          Int.   0.2 ppm              300  Hepatic
                                          Chr.   0.05 ppm            1000  Neurol.

CHLORPYRIFOS                        Oral  Acute  0.003 mg/kg/day       10  Neurol.   Final  09/97  002921-88-2
                                          Int.   0.003 mg/kg/day       10  Neurol.
                                          Chr.   0.001 mg/kg/day      100  Neurol.

CHROMIUM(VI), AEROSOL MISTS         Inh.  Int.   0.000005 mg/m³       100  Resp.     Final  09/00  007738-94-5

CHROMIUM(VI), PARTICULATES          Inh.  Int.   0.001 mg/m³           30  Resp.     Final  09/00  018540-29-9

COBALT                              Inh.  Chr.   0.0001 mg/m³          10  Resp.     Draft  09/01  007440-48-4
                                    Oral  Int.   0.01 mg/kg/day       100  Hemato.
                                    Rad.  Acute  4 mSv                  3  Develop.
                                          Chr.   1 mSv/yr               3  Other

COPPER                              Oral  Acute  0.02 mg/kg/day         3  Gastro    Draft  09/02   007440-50-8
                                          Int.   0.02 mg/kg/day         3  Gastro 

CRESOL, META-                       Oral  Acute  0.05 mg/kg/day       100  Resp.     Final  07/92  000108-39-4

CRESOL, ORTHO-                      Oral  Acute  0.05 mg/kg/day       100  Neurol.   Final  07/92  000095-48-7

CRESOL, PARA-                       Oral  Acute  0.05 mg/kg/day       100  Neurol.   Final  07/92  000106-44-5

CYANIDE, SODIUM                     Oral  Int.   0.05 mg/kg/day       100  Repro.    Final  09/97  000143-33-9

CYCLOTETRAMETHYLENE TETRANITRAMINE  Oral  Acute  0.1 mg/kg/day       1000  Neurol.   Final  09/97  002691-41-0
(HMX)                                     Int.   0.05 mg/kg/day      1000  Hepatic

CYCLOTRIMETHYLENETRINITRAMINE (RDX) Oral  Acute  0.06 mg/kg/day       100  Neurol.   Final  06/95  000121-82-4
                                          Int.   0.03 mg/kg/day       300  Repro.

CYHALOTHRIN                         Oral  Acute  0.01 mg/kg/day       100  Gastro.   Final  09/03  068085-85-8
                                          Int.   0.01 mg/kg/day       100  Gastro. 

CYPERMETHRIN                        Oral  Acute  0.02 mg/kg/day       100  Neurol.   Final  09/03  052315-07-8

DDT, P,P'-                          Oral  Acute  0.0005 mg/kg/day    1000  Develop.  Final  09/02  000050-29-3
                                          Int.   0.0005 mg/kg/day     100  Hepatic

DI(2-ETHYLHEXYL)PHTHALATE           Oral  Int.   0.1 mg/kg/day        100  Repro.    Final  09/02  000117-81-7
                                          Chr.   0.06 mg/kg/day       100  Repro.    

DI-N-BUTYL PHTHALATE                Oral  Acute  0.5 mg/kg/day        100  Develop.  Final  09/01  000084-74-2

DI-N-OCTYL PHTHALATE                Oral  Acute  3 mg/kg/day          300  Hepatic   Final  09/97  000117-84-0
                                          Int.   0.4 mg/kg/day        100  Hepatic

DIAZINON                            Inh.  Int.   0.009 mg/m³           30  Neurol.   Final  08/96  000333-41-5
                                    Oral  Int.   0.0002 mg/kg/day     100  Neurol.

DICHLORVOS                          Inh.  Acute  0.002 ppm            100  Neurol.   Final  09/97  000062-73-7
                                          Int.   0.0003 ppm           100  Neurol.
                                          Chr.   0.00006 ppm          100  Neurol.
                                    Oral  Acute  0.004 mg/kg/day     1000  Neurol.
                                          Int.   0.003 mg/kg/day       10  Neurol.
                                          Chr.   0.0005 mg/kg/day     100  Neurol.

DIELDRIN                            Oral  Int.   0.0001 mg/kg/day     100  Neurol.   Final  09/02  000060-57-1
                                          Chr.   0.00005 mg/kg/day    100  Hepatic

DIETHYL PHTHALATE                   Oral  Acute  7 mg/kg/day          300  Repro.    Final  06/95  000084-66-2
                                          Int.   6 mg/kg/day          300  Hepatic

DIISOPROPYL METHYLPHOSPHONATE       Oral  Int.   0.8 mg/kg/day        100  Hemato.   Final  10/98  001445-75-6
(DIMP)                                    Chr.   0.6 mg/kg/day        100  Hemato.

DISULFOTON                          Inh.  Acute  0.006 mg/m³           30  Neurol.   Final  08/95  000298-04-4
                                          Int.   0.0002 mg/m³          30  Neurol.
                                    Oral  Acute  0.001 mg/kg/day      100  Neurol.
                                          Int.   0.00009 mg/kg/day    100  Develop.
                                          Chr.   0.00006 mg/kg/day   1000  Neurol.

ENDOSULFAN                          Oral  Int.   0.005 mg/kg/day      100  Immuno.   Final  09/00  000115-29-7
                                          Chr.   0.002 mg/kg/day      100  Hepatic

ENDRIN                              Oral  Int.   0.002 mg/kg/day      100  Neurol.   Final  08/96  000072-20-8
                                          Chr.   0.0003 mg/kg/day     100  Neurol.

ETHION                              Oral  Acute  0.002 mg/kg/day       30  Neurol.   Final  09/00  000563-12-2
                                          Int.   0.002 mg/kg/day       30  Neurol.
                                          Chr.   0.0004 mg/kg/day     150  Neurol.

ETHYLBENZENE                        Inh.  Int.   1.0 ppm              100  Develop.  Final  07/99  000100-41-4

ETHYLENE GLYCOL                     Inh.  Acute  0.5 ppm              100  Renal     Final  09/97  000107-21-1
                                    Oral  Acute  2.0 mg/kg/day        100  Develop.
                                          Chr.   2.0 mg/kg/day        100  Renal

ETHYLENE OXIDE                      Inh.  Int.   0.09 ppm             100  Renal     Final  12/90  000075-21-8

FLUORANTHENE                        Oral  Int.   0.4 mg/kg/day        300  Hepatic   Final  08/95  000206-44-0

FLUORENE                            Oral  Int.   0.4 mg/kg/day        300  Hepatic   Final  08/95  000086-73-7

FLUORIDE, SODIUM                    Oral  Chr.   0.05 mg/kg/day         3  Musculo.  Final  09/03  007681-49-4

FLUORINE                            Inh.  Acute  0.01 ppm              10  Resp.     Final  09/03 007782-41-4

FORMALDEHYDE                        Inh.  Acute  0.04 ppm               9  Resp.     Final  07/99  000050-00-0
                                          Int.   0.03 ppm              30  Resp.
                                          Chr.   0.008 ppm             30  Resp.
                                    Oral  Int.   0.3 mg/kg/day        100  Gastro.
                                          Chr.   0.2 mg/kg/day        100  Gastro.

FUEL OIL NO. 2                      Inh.  Acute  0.02 mg/m³          1000  Neurol.   Final  06/95  068476-30-2

HEXACHLOROBENZENE                   Oral  Acute  0.008 mg/kg/day      300  Develop.  Final  09/02  000118-74-1
                                          Int.   0.0001 mg/kg/day      90  Repro.
                                          Chr.   0.00005 mg/kg/day    300  Develop.

HEXACHLOROBUTADIENE                 Oral  Int.   0.0002 mg/kg/day    1000  Renal     Final  05/94  000087-68-3

HEXACHLOROCYCLOHEXANE, ALPHA-       Oral  Chr.   0.008 mg/kg/day      100  Hepatic   Draft  09/03  000319-84-6

HEXACHLOROCYCLOHEXANE, BETA-        Oral  Acute  0.2 mg/kg/day        100  Neurol.   Draft  09/03  000319-85-7
                                          Int.   0.0006 mg/kg/day     300  Hepatic

HEXACHLOROCYCLOHEXANE, GAMMA-       Oral  Acute  0.003 mg/kg/day      300  Develop.  Draft  09/03  000058-89-9
                                          Int.   0.00001 mg/kg/day   1000  Immuno.

HEXACHLOROCYCLOPENTADIENE           Inh.  Int.   0.01 ppm              30  Resp.     Final  07/99  000077-47-4
                                          Chr.   0.0002 ppm            90  Resp.
                                    Oral  Int.   0.1 mg/kg/day        100  Renal

HEXACHLOROETHANE                    Inh.  Acute  6 ppm                 30  Neurol.   Final  09/97  000067-72-1
                                          Int.   6 ppm                 30  Neurol.
                                    Oral  Acute  1 mg/kg/day          100  Hepatic
                                          Int.   0.01 mg/kg/day       100  Hepatic

HEXAMETHYLENE DIISOCYANATE          Inh.  Int.   0.00003 ppm           30  Resp.     Final  10/98  000822-06-0
                                          Chr.   0.00001 ppm           90  Resp.

HEXANE, N-                          Inh.  Chr.   0.6 ppm              100  Neurol.   Final  07/99  000110-54-3

HYDRAZINE                           Inh.  Int.   0.004 ppm            300  Hepatic   Final  09/97  000302-01-2

HYDROGEN FLUORIDE                   Inh.  Acute  0.02 ppm              30  Resp.     Final  09/03  007664-39-3

HYDROGEN SULFIDE                    Inh.  Acute  0.07 ppm              30  Resp.     Final  07/99  007783-06-4
                                          Int.   0.03 ppm              30  Resp.

IODIDE                              Oral  Acute  0.01 mg/kg/day         1  Endocr.   Draft  09/01  007553-56-2
                                          Chr.   0.01 mg/kg/day         1  Endocr.

IONIZING RADIATION, N.O.S.          Rad.  Acute  4 mSv                  3  Neurol.   Final  09/99  HZ1800-45-T
                                          Chr.   1 mSv/yr               3  Other

ISOPHORONE                          Oral  Int.   3 mg/kg/day          100  Other     Final  12/89  000078-59-1
                                          Chr.   0.2 mg/kg/day       1000  Hepatic

JP-4                                Inh.  Int.   9 mg/m³              300  Hepatic   Final  06/95  050815-00-4

JP-5/JP-8                           Inh.  Int.   3 mg/m³              300  Hepatic   Final  10/98  HZ0600-26-T

JP-7                                Inh.  Chr.   0.3 mg/m³            300  Hepatic   Final  06/95  HZ0600-22-T

KEROSENE                            Inh.  Int.   0.01 mg/m³          1000  Hepatic   Final  06/95  008008-20-6

MALATHION                           Inh.  Acute  0.2 mg/m³            100  Neurol.   Final  09/03  000121-75-5
                                          Int.   0.02 mg/m³          1000  Resp.
                                    Oral  Int.   0.02 mg/kg/day        10  Neurol.
                                          Chr.   0.02 mg/kg/day       100  Neurol.

MANGANESE                           Inh.  Chr.   0.00004 mg/m³        500  Neurol.   Final  09/00  007439-96-5

MERCURIC CHLORIDE                   Oral  Acute  0.007 mg/kg/day      100  Renal     Final  03/99  007487-94-7
                                          Int.   0.002 mg/kg/day      100  Renal

MERCURY                             Inh.  Chr.   0.0002 mg/m³           30  Neurol.   Final  03/99  007439-97-6

METHOXYCHLOR                        Oral  Int.   0.005 mg/kg/day      1000  Repro.    Draft  09/00  000072-43-5

METHYL PARATHION                    Oral  Int.   0.0007 mg/kg/day      300  Neurol.   Final  09/01  000298-00-0
                                          Chr.   0.0003 mg/kg/day      100  Hemato.

METHYL-T-BUTYL ETHER                Inh.  Acute  2 ppm                 100  Neurol.   Final  08/96  001634-04-4
                                          Int.   0.7 ppm               100  Neurol.
                                          Chr.   0.7 ppm               100  Renal
                                    Oral  Acute  0.4 mg/kg/day         100  Neurol.
                                          Int.   0.3 mg/kg/day         300  Hepatic

METHYLENE CHLORIDE                  Inh.  Acute  0.6 ppm               100  Neurol.   Final  09/00  000075-09-2
                                          Int.   0.3 ppm                90  Hepatic
                                          Chr.   0.3 ppm                30  Hepatic
                                    Oral  Acute  0.2 mg/kg/day         100  Neurol.
                                          Chr.   0.06 mg/kg/day        100  Hepatic

METHYLMERCURY                       Oral  Chr.   0.0003 mg/kg/day        4  Develop.  Final  03/99  022967-92-6

MIREX                               Oral  Chr.   0.0008 mg/kg/day      100  Hepatic   Final  08/95  002385-85-5

N-NITROSODI-N-PROPYLAMINE           Oral  Acute  0.095 mg/kg/day       100  Hepatic   Final  12/89  000621-64-7

NAPHTHALENE                         Inh.  Chr.   0.0007 ppm            300  Resp.     Draft  09/03  000091-20-3
                                    Oral  Acute  0.6 mg/kg/day          90  Neurol.
                                          Int.   0.6 mg/kg/day          90  Neurol.

NICKEL                              Inh.  Int.   0.0002 mg/m³           30  Resp.     Draft  09/03  007440-02-0
                                          Chr.   0.00009 mg/m³          30  Resp.

PENTACHLOROPHENOL                   Oral  Acute  0.005 mg/kg/day      1000  Develop.  Final  09/01  000087-86-5
                                          Int.   0.001 mg/kg/day      1000  Repro.
                                          Chr.   0.001 mg/kg/day      1000  Endocr.

PERMETHRIN                          Oral  Acute  0.3 mg/kg/day        100  Neurol.   Final  09/03  052645-53-1
                                          Int.   0.2 mg/kg/day        100  Neurol.
   
PHOSPHORUS, WHITE                   Inh.  Acute  0.02 mg/m³             30  Resp.     Final  09/97  007723-14-0
                                    Oral  Int.   0.0002 mg/kg/day      100  Repro.

POLYBROMINATED BIPHENYLS (PBBs)     Oral  Acute  0.01 mg/kg/day        100  Endocr.   Draft  09/02  067774-32-7

POLYBROMINATED DIPHENYL ETHERS      Oral  Acute  0.03 mg/kg/day         30  Endocr.   Draft  09/02  032534-81-9
                                          Int.   0.007 mg/kg/day       300  Hepatic  

POLYCHLORINATED BIPHENYLS (PCBs)    Oral  Int.   0.03 ug/kg/day        300  Neurol.   Final  11/00  011097-69-1
Aroclor 1254                              Chr.   0.02 ug/kg/day        300  Immuno.

PROPYLENE GLYCOL DINITRATE          Inh.  Acute  0.003 ppm              10  Neurol.   Final  06/95  006423-43-4
                                          Int.   0.00004 ppm          1000  Hemato.
                                          Chr.   0.00004 ppm          1000  Hemato.

PROPYLENE GLYCOL                    Inh.  Int.   0.009 ppm            1000  Resp.     Final  09/97  000057-55-6

REFRACTORY CERAMIC FIBERS           Inh.  Chr.   0.03 fibers/cc         30  Resp.     Draft  09/02   HZ0900-26-T

SELENIUM                            Oral  Chr.   0.005 mg/kg/day         3  Dermal    Final  09/03  007782-49-2

STRONTIUM                           Oral  Int.   2 mg/kg/day            30  Musculo.  Draft  07/01  007440-24-6

STYRENE                             Inh.  Chr.   0.06 ppm              100  Neurol.   Final  09/92  000100-42-5
                                    Oral  Int.   0.2 mg/kg/day        1000  Hepatic
SULFUR DIOXIDE                      Inh.  Acute  0.01 ppm                9  Resp.     Final  12/98  007446-09-5

SULFUR MUSTARD                      Inh.  Acute  0.0007 mg/m³           30  Ocular    Final   09/03  000505-60-2
                                          Int.   0.00002 mg/m³          30  Ocular
                                    Oral  Acute  0.5 ug/kg/day        1000  Develop.
                                          Int.   0.07 ug/kg/day        300  Gastro.

TETRACHLOROETHYLENE                 Inh.  Acute  0.2 ppm                10  Neurol.   Final  09/97  000127-18-4
                                          Chr.   0.04 ppm              100  Neurol.
                                    Oral  Acute  0.05 mg/kg/day        100  Develop.

TIN, INORGANIC                      Oral  Int.   0.3 mg/kg/day         100  Hemato.   Draft 09/03   007440-31-5

TIN, DIBUTYL                        Oral  Int.   0.005 mg/kg/day       1000 Immunol.  Draft 09/03   000683-18-1

TIN, TRIBUTYL                       Oral  Int.   0.0003 mg/kg/day       100 Immunol.  Draft  09/03  000056-36-9                                              Chr.   0.0003 mg/kg/day       100 Immunol.
   
TITANIUM TETRACHLORIDE              Inh.  Int.   0.01 mg/m³             90  Resp.     Final  09/97  007550-45-0
                                          Chr.   0.0001 mg/m³           90  Resp.
																	
TOLUENE                             Inh.  Acute  1 ppm                  10  Neurol.   Final  09/00  000108-88-3
                                          Chr.   0.08 ppm              100  Neurol.
                                    Oral  Acute  0.8 mg/kg/day         300  Neurol.
                                          Int.   0.02 mg/kg/day        300  Neurol.

TOXAPHENE                           Oral  Acute  0.005 mg/kg/day      1000  Hepatic   Final  08/96  008001-35-2
                                          Int.   0.001 mg/kg/day       300  Hepatic

TRICHLOROETHYLENE                   Inh.  Acute  2 ppm                  30  Neurol.   Final  09/97  000079-01-6
                                          Int.   0.1 ppm               300  Neurol.
                                    Oral  Acute  0.2 mg/kg/day         300  Develop.

URANIUM, HIGHLY SOLUBLE SALTS       Inh.  Int.   0.0004 mg/m³           90  Renal     Final  09/99  HZ1800-90-T
                                          Chr.   0.0003 mg/m³           30  Renal
                                    Oral  Int.   0.002 mg/kg/day        30  Renal

URANIUM, INSOLUBLE COMPOUNDS        Inh.  Int.   0.008 mg/m³            30  Renal     Final  09/99  HZ1800-92-T

VANADIUM                            Inh.  Acute  0.0002 mg/m³          100  Resp.     Final  07/92  007440-62-2
                                    Oral  Int.   0.003 mg/kg/day       100  Renal

VINYL ACETATE                       Inh.  Int.   0.01 ppm              100  Resp.     Final  07/92  000108-05-4

VINYL CHLORIDE                      Inh.  Acute  0.5 ppm               100  Develop.  Final  09/97  000075-01-4
                                          Int.   0.03 ppm              300  Hepatic
                                    Oral  Chr.   0.00002 mg/kg/day    1000  Hepatic

XYLENE, M-                          Oral  Int.   0.6 mg/kg/day        1000  Hepatic   Final  08/95  000108-38-3

XYLENE, P-                          Oral  Acute  1 mg/kg/day           100  Neurol.   Final  08/95  000106-42-3

XYLENES, TOTAL                      Inh.  Acute  1 ppm                 100  Neurol.   Final  08/95  001330-20-7
                                          Int.   0.7 ppm               300  Develop.
                                          Chr.   0.1 ppm               100  Neurol.
                                    Oral  Int.   0.2 mg/kg/day        1000  Renal

ZINC                                Oral  Int.   0.3 mg/kg/day           3  Hemato.   Draft  09/03  007440-66-6
                                          Chr.   0.3 mg/kg/day           3  Hemato.

1-METHYLNAPHTHALENE                 Oral  Chr.   0.07 mg/kg/day       1000  Resp.     Draft  09/03   000090-12-0

2-METHYLNAPHTHALENE                 Oral  Chr.   0.05 mg/kg/day       1000  Resp.     Draft 09/03   000091-20-3

1,1-DICHLOROETHENE                  Inh.  Int.   0.02 ppm              100  Hepatic   Final  05/94  000075-35-4
                                    Oral  Chr.   0.009 mg/kg/day      1000  Hepatic

1,1-DIMETHYLHYDRAZINE               Inh.  Int.   0.0002 ppm            300  Hepatic   Final  09/97  000057-14-7

1,1,1-TRICHLOROETHANE               Inh.  Acute  2 ppm                 100  Neurol.   Final  08/95  000071-55-6
                                          Int.   0.7 ppm               100  Neurol.

1,1,2-TRICHLOROETHANE               Oral  Acute  0.3 mg/kg/day         100  Neurol.   Final  12/89  000079-00-5
                                          Int.   0.04 mg/kg/day        100  Hepatic

1,1,2,2-TETRACHLOROETHANE           Inh.  Int.   0.4 ppm               300  Hepatic   Final  08/96  000079-34-5
                                    Oral  Int.   0.6 mg/kg/day         100  Body Wt.
                                          Chr.   0.04 mg/kg/day       1000  Resp.

1,2-DIBROMO-3-CHLOROPROPANE         Inh.  Int.   0.0002 ppm            100  Repro.    Final  09/92  000096-12-8
                                    Oral  Int.   0.002 mg/kg/day      1000  Repro.

1,2-DICHLOROETHENE, CIS-            Oral  Acute  1 mg/kg/day           100  Hemato.   Final  08/96  000156-59-2
                                          Int.   0.3 mg/kg/day         100  Hemato.

1,2-DICHLOROETHANE                  Inh.  Chr.   0.6 ppm                90  Hepatic   Final  09/01  000107-06-2
                                    Oral  Int.   0.2 mg/kg/day         300  Renal

1,2-DICHLOROPROPANE                 Inh.  Acute  0.05 ppm             1000  Resp.     Final  12/89  000078-87-5
                                          Int.   0.007 ppm            1000  Resp.
                                    Oral  Acute  0.1 mg/kg/day        1000  Neurol.
                                          Int.   0.07 mg/kg/day       1000  Hemato.
                                          Chr.   0.09 mg/kg/day       1000  Hepatic

1,2-DICHLOROETHENE, TRANS-          Inh.  Acute  0.2 ppm              1000  Hepatic   Final  08/96  000156-60-5
                                          Int.   0.2 ppm              1000  Hepatic
                                    Oral  Int.   0.2 mg/kg/day         100  Hepatic

1,2-DIMETHYLHYDRAZINE               Oral  Int.   0.0008 mg/kg/day     1000  Hepatic   Final  09/97  000540-73-8

1,2,3-TRICHLOROPROPANE              Inh.  Acute  0.0003 ppm            100  Resp.     Final  09/92  000096-18-4
                                    Oral  Int.   0.06 mg/kg/day        100  Hepatic

1,3-DICHLOROPROPENE                 Inh.  Int.   0.003 ppm             100  Resp.     Final  09/92  000542-75-6
                                          Chr.   0.002 ppm             100  Resp.

1,3-DINITROBENZENE                  Oral  Acute  0.008 mg/kg/day       100  Repro.    Final  06/95  000099-65-0
                                          Int.   0.0005 mg/kg/day     1000  Hemato.

1,4-DICHLOROBENZENE                 Inh.  Acute  0.8 ppm               100  Develop.  Final  12/98  000106-46-7
                                          Int.   0.2 ppm               100  Hepatic
                                          Chr.   0.1 ppm               100  Hepatic
                                    Oral  Int.   0.4 mg/kg/day         300  Hepatic

2-BUTOXYETHANOL                     Inh.  Acute  6 ppm                   9  Hemato.   Final  10/98  000111-76-2
                                          Int.   3 ppm                   9  Hemato.
                                          Chr.   0.2 ppm                 3  Hemato.
                                    Oral  Acute  0.4 mg/kg/day          90  Hemato.
                                          Int.   0.07 mg/kg/day       1000  Hepatic

2,3,4,7,8-PENTACHLORODIBENZOFURAN   Oral  Acute  0.001 ug/kg/day      3000  Immuno.   Final  05/94  057117-31-4
                                          Int.   0.00003 ug/kg/day    3000  Hepatic

2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN Oral  Acute  0.0002 ug/kg/day       21  Immuno.   Final  12/98  001746-01-6
                                          Int.   0.00002 ug/kg/day      30  Lymphor.
                                          Chr.   0.000001 ug/kg/day     90  Develop.

2,4-DICHLOROPHENOL                  Oral  Int.   0.003 mg/kg/day       100  Immuno.   Final  07/99  000120-83-2

2,4-DINITROPHENOL                   Oral  Acute  0.01 mg/kg/day        100  Body Wt.  Final  08/95  000051-28-5

2,4-DINITROTOLUENE                  Oral  Acute  0.05 mg/kg/day        100  Neurol.   Final  12/98  000121-14-2
                                          Chr.   0.002 mg/kg/day       100  Hemato.

2,4,6-TRINITROTOLUENE               Oral  Int.   0.0005 mg/kg/day     1000  Hepatic   Final  06/95  000118-96-7

2,6-DINITROTOLUENE                  Oral  Int.   0.004 mg/kg/day      1000  Hemato.   Final  12/98  000606-20-2

4-CHLOROPHENOL                      Oral  Acute  0.01 mg/kg/day        100  Hepatic   Final  07/99  000106-48-9

4,4'-METHYLENEBIS(2-CHLOROANILINE)  Oral  Chr.   0.003 mg/kg/day      3000  Hepatic   Final  05/94  000101-14-4

4,4'-METHYLENEDIANILINE             Oral  Acute  0.2 mg/kg/day         300  Hepatic   Final  10/98  000101-77-9
                                          Int.   0.08 mg/kg/day        100  Hepatic

4,6-DINITRO-O-CRESOL                Oral  Acute  0.004 mg/kg/day       100  Neurol.   Final  08/95  000534-52-1
                                          Int.   0.004 mg/kg/day       100  Neurol.
______________________________________________________________________________________________________________
Total number of MRLs: 326

Dr. Selene Chou / CJC3@cdc.gov

This page was updated on May 11, 2004