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PLAINTIFF'S EXHIBIT I. DOW CHEMICAL ..// // // TEXAS 0!un0*s FREEPORT. TEXAS mil March 26, 1987 X " ^ F. D. Axe, Pittsburg VJ.' ErTedfc^7^aqugnine G. L. Meier, Strongsville L. W. Rangy, Midland A. W. Schaffer, Midland ur RECEIVED apr os mi INDUSTRIAL HYGIENE SERVICES cc: ZHS staff Estimating Degrees of Exposure and Priority (Hazard) Rating, far our industrial hygiene inventories, is a very subjective process. We juggle a number of variables trying to find the one category that best describes a specific job class/stress oraihl nation. /iX L ^ 00^ I have tried to take some of the mystery cut of the process by defining the variables and applying a simplified system of weighting factors. By multiplying the factors, far all variables, I get a single number far Degree of Exposure ar Priority Rating. Using my judgement, I have devised a range of values that correspond to each category of the two rating systems. I am not suggesting that this approach be used to estimate all degrees of exposure and priority ratings in a given inventory. Instead, this system can be used as a spot check far consistency and to help with difficult, assessments. I have found that the plant folks appreciate this technique since they are better able to understand the thinking process. Siis would also be a good training tool far new industrial hygienists. p Please review this rating system, particularly the criteria for selecting the degree of exposure cr priority rating category. Let me know if you can envision circumstances where ay range of values do not result in the "appropriate" rating. If we can all agree on the criteria, we would have a useful tool that could be passed cn to the rest of the industrial hygiene ccmunity. George H. Flores Industrial Hygiene Services AN OPERATING UNIT OF THE OOW CHEMICAL COMPANV ^Quafitv= Perfeimante . ESTIMATING DEGREE OF EXPOSURE CO z o2 CO LU _l GL < O CO LU X CL LU O LU XX O UJ Q. CU CO X X LU CU X oz xc X I-- o o X CD x l-H ** XX > X >* XX Xo z o < in cj V > oX CO CO X CO -J Z CO Z X a < z UJ tU H x X 1H CU l-H LU LU -J x ao oo X o I- Q- CL O X \X cu in LU o X^ O -J rt CO Q. C -rl O "*- o 1 CL >- X o > in xa X CO CO O CL LU CO a x L-- CO Z CO X X Z X l-H X o u.cn yri O < X co t-- O CO OX X X -J X o V O _J cj CD _J >- \x in x __i *-< z CJ CO O o LU I ! z II o II z II X Z CJ X Xo o X X CO -J Xa X X _1 X HH o a CJ 1-- z X zo >- o CJ < X < X X >o X o h-- n l-H 1-- X H- X z X t-- _l l-H --I z X z K-- l-H X a a X < h- o X o --1 z - cXXoX < X<>> Imt 1 t-- >- x X a z -< CO cc o o < .. u. < *--I X CL l-H LU CO H- H LU CL X CJ -- CO a. x l-H o X X CO oX XXX XXX X X CO CO o OX X XOX XXX XX X JX XX<o CO O H x CL X _l X < LU *< I-- i- LU IH-H XO Z-- ~ UJ 00 LU LU J-- l-i H- y- o C9 O < CL H Q_ X _J CD 2 LaU Xco LU O O hh XX CU CM CO co 'T I cu I I CO o in CcoO J^L o U. r> 5 \S> on ESTIMATING CO l--1 CO 31 OJ UJ CD CVJ z I--l ^ o UJ X CD 1 o 05 -l >- a O-*-t o ZX LU 3 CD o II CVJ CVi hCO- z"D UJ X o >- HH Z o CO > -J a. a. CD CD CD <t I--l CD CD H* Z Z o < SlflNH CVI OI I H _J X ^ a: a z < CO cr o H- CJ *< X < H-l --l < < X I-- IX X <C < aaXX xx < ao < < INI x x |NJ INI -<<< C * X INIINI < *< UJ X X UJ X UJ UJ o UJ < UJ --I XX > 3 X O UJ HH O xx o fN. < X UJ CO UJ X Xu K- O GO CD CVI CO ^ > z OJ -r* _J w I I GO XX I I UJ X HH o << co tncon /v CO C"yO o X\ X X CD 30 JL X X X Xz o UJ CJ H 1 1 UJ CJ X u < o UJ X x a UJ --t X UJ X CD o 1--1 CD UJ ~T~ X o o 1--1 h- D O oO o rq DEGREE OF EXPOSURE RATINGS The degTee of exposure (DE) rating is a means of qualitatively estimating employees' potential exposure to those chemical and physical agents present in the workplace. Degree of exposure ratings may vary by job assignment. They provide a relative ranking of exposure potential which has the greatest validity within a plant rather than between different plants. Degree of exposure ratings are Intended to describe exposure under normal operating conditions. The degree of exposure is based primarily on the type of operation or condition of use; however, other factors such as the physical properties of the material, general and local ventilation are also considered. It should be emphasized that these ratings are based on the employees' potential degree of exposure; that is, the exposure to be expected if personal protective equipment is not worn. When assigning degree of exposure ratings to a particular Job category, any infrequent but routine Job tasks and maintenance procedures should be taken into consideration. In other words, the worst case for routine potential expo sure should be factored into the overall degree of exposure rating for that Job category. Plant supervision and industrial hygienists use the following four categories as guidelines for determining the degree of exposure rating. DE Description NEG Within this Job assignment*, the normal conditions of use and the physical properties of the material indicate that both inhalation and skin exposures are likely to be no more than negligible. Characterized by remote handling operations with the equipment iso lated from the employees' work area. There is no equivalent exposure category on the T.I.M.E. system since the categories on the T.I.M.E. system serve primarily to determine appropriate handling precautions for known exposure situations. Typical job assignments which might be assigned a DE rating of 'NEG' include computer personnel and secretaries. LOW Within this job assignment, tbe normal conditions of use and the physical properties of the material indicate that both inhalation and skin exposure are likely to be no more than minor. Characterized by work around closed systems; sampling, laboratory work, packaging or dumping of materials with low to moderate volatility or dustiness with sufficient ventilation. The equivalent T.I.M.E. system category would be 'LOW', ^ hbZ C t-00- ^ Job assignment is defined as a group of employees doing the same type of work which results in their having comparable exposures. 11/86 2 MOD EIGH Within this job assignment, the normal conditions of use and the physical properties of the material indicate that there is a potential for moderate inhalation and/or skin exposures. Characterized by manual handling of materials such as sampling, packaging, filter changing or dumping of materials with low to moderate volatility or dustiness using potentially insufficient ventilation. This category may also include handling of materials with high volatility or dustiness if sufficient local exhaust ventilation is present. The equivalent T.I.M.E. system category would be 'MOD'. Within this job assignment, the normal conditions of use and the physical properties of the material indicate that there is a potential for high inhalation and/or skin exposures. ' Characterized by manual operations such as sampling, packaging, filter changing or dumping of materials with high volatility or dustiness without sufficient local exhaust ventilation. Control is generally .achieved through extensive use of protective equipment. The equivalent T.I.M.E. system category would be ,HIGHt. .9 /.bSttoois 11/86 3 PRIORITY RATINGS The priority rating1 is useful for representing and communicating the risks present in particular work situations. It is also helpful in establishing industrial hygiene priorities. The priority rating is based on two things: the conditions of use and physical properties (Degree of Exposure Rating), and the toxicity and warning properties of the material (Industrial Hygiene Guide if available). Within a given plant, the rating for a single chemical may be different for various job assignments because of the varying degree of exposure. Industrial hygienists use the following six categories as guidelines for assigning the priority ratings. PR Description 5 The degree of exposure rating, the toxicity of the material, and the warning properties are such that, for this job assignment under normal operating conditions, there is a negligible potential for exposures to approach or exceed acceptable levels. - No further exposure evaluation is needed. 4 The degree of exposure rating, the toxicity of the material, and the warning properties are such that, for this job assignment under normal operating conditions, there is a minor potential for exposures to approach or exceed acceptable levels. Only minimal monitoring may be needed to confirm this rating. 3 The degree of exposure rating, the toxicity of the material, and its warning properties are such that, for this job assignment under normal operating conditions, there is a moderate potential for exposures to approach or exceed acceptable levels. Employees' exposures should be monitored regularly or subjectively evaluated by a health professional. 2 The degree of exposure rating, the toxicity of the material, and the warning properties are such that, for this job assignment under normal operating conditions, there is a significant potential for exposures to approach or exceed acceptable levels. Periodic monitoring should be initiated and employees' exposure levels reevaluated on a regular basis. 11/86  '> 4 The degree of exposure rating, the toxicity of the material, and the warning properties are such that, for this job assignment under normal operating conditions, there is a high potential for exposures to exceed acceptable levels. Immediate action by plant supervision and industrial hygiene is necessary to evaluate and control employees' exposure levels to eliminate this high exposure potential. Periodic follow-up docu mentation is needed to ensure control measures are effective. T This "T" category is available to indicate that training has been con ducted on certain chemicals which may be encountered on a nonroutine or emergency basis. No degree of exposure* is assigned with this "T" rating since exposures may never occur or may occur to an unpredict able degree. Situations which may be appropriate for a "T" priority rating include: a. For Security, Fire and Emergency Eesponse Groups - Typically, training is conducted on selected chemicals which may be encountered in an emergency situation. b. For Service Groups - Training may be conducted on chemicals which are not part of a group's own inventory, but which have the potential for being encoun tered based on the type and location of the job being performed. ro> cQ 3 ia Note A dash (-) is used under degree of exposure when a "T" is assigned as a priority rating. 11/86