Environmental Law and Policy Salzman & Thompson

Transcription

1 Environmental Law and Policy Salzman & Thompson Ch.6/7: Regulating Toxic Substances HWR415/515 The University of Arizona

2 Summary I. The Difficulties of Regulating Toxic Substances A. Is Tolerable Risk an Oxymoron? B. The Problem of Uncertainty 1. The paucity of information 2. The difficulty of determining cancer risk 3. Regulating under uncertainty II. Major Regulatory Options A. Pure Health based Statutes B. Feasibility Statutes C. Risk Benefit Statutes 1. Federal Insecticide, Fungicide and Rodenticide Act 2. Toxic Substances Control Act 3. Paralysis by Analysis 4. Criticisms D. Informational Approaches 1. The Toxic release Inventory 2. CA s Proposition 65 HWR415/515 The University of Arizona

3 Discussion: I. The Difficulties of Regulating Toxic Substances i Do you agree with: Life is not risk free If some risks are too small to regulate, where is the dividing line? It is not enough to know only the probability of harm A. Is Tolerable Risk an Oxymoron? Should the gov t regulate chemicals that pose lower risks than everyday activities? The acceptability of risk involves a balancing of probability and severity (including dread) Is it OK to assess voluntary risks differently than imposed risks? Some risks seem less equitable than others Diffuse vs. Concentrated industries. HWR415/515 The University of Arizona

4 Regulating Under Uncertainty A. Benzene (448 US 607, 1980) OSHA regs: What is acceptable risk? 6(b)(5) exposure set at level which most adequately assures that no employee will suffer health problem, even exposed for life 3(8) exposure set at levels reasonably necessary to provide safe or healthful places of employment 448 US 607 (1980) ban only exposures that present a significant risk of material health impairment OSHA only requires a safe work place not one that is risk free Concurring opinion OSHA unconstitutional HWR415/515 The University of Arizona

5 Regulating Under Uncertainty Precautionary discretion B. Taconite (asbestos)(514 F.2d 492, 8 th Cir. 1975) EPA (CWA) release of tailings into Lake Superior 8 th Circuit panel a mere medical hypothesis was insufficient to justify abatement 8 th Circuit Ct Gov t need only show a reasonable medical concern for public health evidence of potential harm as well as actual harm sufficient C. Lead in Gasoline (541 F.2d 1, DC Cir 1976) EPA (CAA) regulation of additives that endanger public health DC Circuit Agencies need not meet scientific standards of proof before regulation potentially harmful substances HWR415/515 The University of Arizona

6 I. The Difficulties of Regulating Toxic Substances ii B. The Problem of Uncertainty The paucity of information NAS (1984): toxicity info on most chemicals is scanty Extensive testing only where warranted by category/form or intended use may ignore some significant risks if not carcinogenic does not consider synergistic effects The difficulty of determining cancer risk Epidemiology studies can only be done after a significant unintended exposure Animal bioassays variability of animal species to various cancers and susceptibility translating animal exposure to human exposure (weight or area?) extrapolating from high levels of exposure to low levels in vito cell and tissue cultures (better?) HWR415/515 The University of Arizona

7 II. Major Regulatory Options A. Pure Health based Statutes FDA Delaney Clauses unsafe additives in foods, drugs, cosmetics Only apply to additives, not naturally occurring carcinogens No harm? few additives are of sig. economic or societal benefit Better? risk risk comparisons 1996 extended to raw foods Acceptable threshold: 1 in a million B. Feasibility Statutes OSHA, SDWA exposure stds must be both tech. and economically feasible MCGL no known or anticipated adverse effects w safety margin MCL s as close to goals as is feasible (water supply std) MCL s (1996) maximize health risk reduction benefits at a cost justified by benefits C. Risk Benefit Statutes FIFRA when used correctly, will not pose an unreasonable risk to man or the environment, taking into account all benefits HWR415/515 The University of Arizona

8 II. Major Regulatory Options D. Informational Approaches Toxic release Inventory List of 650 hazardous substances Goal: reduce releases by 33% by 1992 and 50% by 1995 California s Proposition 65 Business has the burden of proof Threshold: 1:100,000 Paralysis by Analysis Corrosion Proof Fittings (947 F.2d 1201, 5 th Cir) Asbestos; cost/death ~ $2.4 million after 45,000 page analysis, court said effort was lacking: no marginal analysis 13 yrs too short a future outlook period HWR415/515 The University of Arizona

9 Dose Dose: The amount of chemical entering the body This is usually given as mg of chemical/kg of body weight = mg/kg The dose is dependent upon: *The environmental concentration *The properties of the toxicant *The frequency of exposure *The length of exposure *The exposure pathway (route) Arizona Water Issues The University of Arizona HWR 203 Adopted from: Casarez/ Donnelly 9

10 Dose Response Relationship: As the dose of a toxicant increases, so does the response 4 Limitations Often derived from acute exposure data. Species variation RESPONSE 3 Ranges: 4 Maximum Response 2-3 Linear Range 0-1 NOAEL DOSE Arizona Water Issues Dose determines the biological response The University of Arizona HWR 203 Adopted from: Casarez/ Donnelly 10

11 LD50 Comparison Chemical LD 50 (mg/kg) Ethyl Alcohol 10,000 Sodium Chloride 4,000 Ferrous Sulfate 1,500 Morphine Sulfate 900 Strychnine Sulfate 150 Nicotine 1 (1 mg) Black Widow 0.55 Curare 0.50 Rattle Snake 0.24 Dioxin (TCDD) Botulinum toxin Different toxicants can be compared--lowest dose is most potent Arizona Water Issues The University of Arizona HWR 203 Adopted from: Casarez/ Donnelly 11

12 Sources of Caffeine Source Amount mg / 12 oz Dose if 150lbs ie. 68 kg Coffee - brew /16oz or 3.6 mg/kg Coffee - decaf 5 Iced tea 70 Nestea 25 Coke /36oz or 1.5 mg/kg Mt. Dew 55 Monster, RedBull /24oz or 3.5 mg/kg Source: Arizona Water Issues The University of Arizona HWR 203 Adopted from: Casarez/ Donnelly 12

13 Toxicology Exposure + Hazard = Risk All substances can be a poison Dose determines the response Pathway, Duration of Frequency of Exposure and Chemical determine Dose Absorption, Distribution, Metabolism & Excretion The extent of the effect is dependent upon the concentration of the active compound at its site of action over time Bioactivation: compounds to reactive metabolites Individual variation of the organism will affect ADME Arizona Water Issues The University of Arizona HWR 203 Adopted from: Casarez/ Donnelly 13