Tier 1 Environmental Performance Tools Economic Criteria

Acetone-Cyanohydrin Pathway

Isobutylene Pathway

Raw Material Cost 1st pathway 2nd pathway

Tier 1 Environmental Performance Tools Environmental Criteria

Criteria based on Input-Output Chemical Structures

None of the reactants or products in either scheme bioaccumulate or are persistent in the environment! All of the compounds would have persistence and bioaccumulation ratings of 1.

Threshold Limit Values (TLV) Established by the American Conference of Governmental Industrial Hygienists (ACGIH). The TLV refers to airborne concentrations that correspond to conditions where no adverse effects are normally expected during a worker’s lifetime. The exposure occurs only during normal working hours, eight hours per day and five days per week.

TLV-TWA Time weighted average for a normal 8-hour workday or 40-hour workweek, to which nearly all workers can be exposed, day after day, without adverse effects. Excursions above the limit are allowed if compensated by excursions below the limit.

TLV-STEL Short-term exposure limit. The maximum concentration to which workers can be exposed for a period of up to 15 minutes continuously without suffering (1) intolerable irritation, (2) chronic or irreversible tissue changes, (3) narcosis of sufficient degree to increases accident proneness, or materially reduce worker efficiency, provided that no more than four excursions per day are permitted, and provided that the daily TLV-TWA is not exceed.

TLV-C Ceiling limit. The concentration which should not be exceeded, even instantaneously.

Permissible Exposure Level (PEL) Defined by the United States Occupational Safety and Health Administration (OSHA). The PEL values follow the TLV-TWA very closely. However, they are not as numerous and are not updated as frequently. The TLVs are more conservative.

Recommended Exposure Limit (REL) The National Institute for Occupational Safety and Health (NOISH), under the Centers for Disease Control and Prevention (CDC), publishes REL based on Toxicity research. These values are frequently more current than the OSHA PELs.

Toxicity Index The TLV only accounts for direct human effects via inhalation. Using the TLV as a surrogate for all toxicity impacts is a gross Simplification.

If the response-dose curve for chemical A is to the right of r-d curve for chemical B, then B is more toxic. However,

Toxicity Weighting This system has been developed by the US EPA using data available from EPA’s IRIS (Integrated Risk Information System) database. htmlhttp:// html Three data elements: (1) inhalation reference concentration; (2) oral ingestion slope factor; (3) unit risk.

Reference Concentration An estimate (with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious non-cancer effects during a lifetime.

Oral Slope Factor The slope of a dose response curve in the low dose region. (ingestion, cancer and non-cancer) When low dose linearity cannot be assumed, the SF is the slope of a straight line from 0 dose to the dose at 1% excess risk. (upper bound) Unit: (mg/kg-day)^-1

Unit Risk The upper bound excess lifetime cancer risk estimated to result from continuous exposure to an agent at a concentration of 1 microgram/L in water and 1 microgram/cubic meter in air. (both inhalation and ingestion)

Acrylonitrile Inflammation of nasal tissue, reference concentration: mg/m^3. A probable human carcinogen, –The oral slope factor for carcinogenic risk is 0.54 (mg/kg-day)^-1 –The inhalation unit risk is 6.8*10^-5 per (microgram/m^3)

Weight Assignment Since the oral slope factor for cancer is 0.54, the oral toxicity weight should be Since the inhalation unit risk (for cancer) is 0.068, the toxicity weight should b The overall toxicity weight should be larger of the two, i.e.,

Composite Index (Type 1)

Composite Index (Type 2)

Composite Index (Type 3) Combining persistence, bioaccumulation and toxicity factors into a composite index by assigning ratings. US EPA employs 3 levels of concern for human toxicity –High concern Evidence of adverse effects in human populations Conclusive evidence of severe effects in animal studies. –Moderate concern Suggestive animal studies Data from close chemical analogue Compound class known to produce toxicity –Low concern Chemical that do not meet the criteria for moderate or high concern