An Industry's Guidelines for Risk Assessment - ACS Symposium

5 An Industry's Guidelines for Risk Assessment RICHARD H . DREITH

Downloaded by NATL UNIV OF SINGAPORE on May 6, 2018 | https://pubs.acs.org Publication Date: October 20, 1982 | doi: 10.1021/bk-1982-0204.ch005

Shell Oil Company, Houston, T X 77210

In the absence of a consensus on a b s o l u t e limits of risk, it i s u s e f u l to have a g o a l - o r i e n t e d risk assessment framework f o r d e c i s i o n making and response resource allocation. A f o u r - s t e p process is i n use at S h e l l to e v a l u a t e risks and d e f i n e a p p r o p r i a t e responses. The steps a r e : (1) Hazard Identification, (2) Hazard E v a l u a t i o n , (3) R i s k E v a l u a t i o n , and (4) R i s k Response. The first three steps amount to making a "risk assessment," and the f o u r t h step adds a response definition. A risk classification system s e t t i n g h i g h , low and insignificant categories for risk reflecting unacceptable, v a r i o u s l y a c c e p t a b l e and a c c e p t a b l e r e g i o n s r e s p e c tively are d e f i n e d , and companion l e v e l s of response a c t i o n are p r e s e n t e d . An overview of a site evaluation experience in California i s o u t l i n e d .

R i s k assessment i s a d i f f i c u l t problem area b e i n g addressed by i n d u s t r y and r e g u l a t o r y a g e n c i e s t o d a y . I h a v e f o u n d i n my p r o f e s s i o n a l e x p e r i e n c e i n t h e o i l and c h e m i c a l i n d u s t r y , t h a t when f a c e d w i t h s o l v i n g d i f f i c u l t p r o b l e m s , s o l u t i o n s g e n e r a l l y r e s u l t e d by t a k i n g l o g i c a l and d i s c i p l i n e d a p p r o a c h e s t o r e s o l v e u n c e r t a i n t i e s . We a t S h e l l h a v e d e v e l o p e d and a r e u s i n g g u i d e l i n e s f o r r i s k assessment which a r e a l l o w i n g us t o analyze r i s k s and i d e n t i f y r e a s o n a b l e r e s p o n s e s . The u s e o f t h e s e s y s t e m a t i c p r o c e d u r e s have i m p r o v e d o u r c o n f i d e n c e i n t h e d e c i s i o n s we must make. I n r e s p o n d i n g t o r i s k s i t u a t i o n s , o u r c o n f i d e n c e i s b u i l t on k n o w i n g t h a t t h e r e s p o n s e s a r e d i r e c t i o n a l l y c o r r e c t and a r e a c h i e v i n g our o v e r a l l goal t o reduce r i s k . Of l a t e , I have b e e n d i s a p p o i n t e d b y t h e c o n s e n s u s o p i n i o n which appears t o be growing r e g a r d i n g d e a l i n g w i t h r i s k assessments. From i n f o r m a t i o n i n t h e m e d i a and d i s c u s s i o n s w i t h c o n t e m p o r a r i e s and a g e n c y r e p r e s e n t a t i v e s , I d e t e c t a n o p i n i o n t h a t suggests s o c i e t y i s not ready t o deal s y s t e m a t i c a l l y w i t h 0097-6156/82/0204-0045 $06.00/0 © 1982 American Chemical Society

Long and Schweitzer; Risk Assessment at Hazardous Waste Sites ACS Symposium Series; American Chemical Society: Washington, DC, 1982.


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assessing risk. I n my v i e w , t h o s e who s u p p o r t t h i s c l a i m a r e a s r e m i s s a t t h a t e x t r e m e a s t h o s e who w o u l d now p l a c e t o t a l f a i t h i n s e e m i n g l y h i g h l y p r e c i s e m e t h o d o l o g i e s f o r e x t r a p o l a t i o n s and r i s k a s s e s s m e n t s . A d d i t i o n a l l y , t h e o p i n i o n f o l l o w s t h a t we a r e n o t ready t o t r a n s l a t e c u r r e n t r i s k assessment u n d e r s t a n d i n g i n t o r e g u l a t o r y programs b e i n g implemented. I d o n ' t t h i n k we a t S h e l l a g r e e w i t h e i t h e r o p i n i o n , o r a r e a p a r t o f any c o n s e n s u s e m b r a c i n g t h e s e o p i n i o n s . We w i l l b e d i s a p p o i n t e d , I'm s u r e , i f t h e i m p l e m e n t a t i o n o f e i t h e r t h e R e s o u r c e C o n s e r v a t i o n and R e c o v e r y A c t (RCRA) o r t h e C o m p r e h e n s i v e E n v i r o n m e n t a l R e s p o n s e C o m p e n s a t i o n and L i a b i l i t y A c t (CERCLA) p r o g r a m s p r o c e e d w i t h o u t t h e r e b e i n g i n c o r p o r a t e d a t l e a s t some r e g u l a t o r y allowances f o r assessing a c t u a l r i s k s . The r i s k s p o s e d b y v a r i o u s h a z a r d o u s w a s t e h a n d l i n g a c t i v i t i e s must be a s s e s s e d when j u d g ments on t h e i r a c c e p t a b i l i t y a r e made, s u c h a s d u r i n g t h e p e r m i t t i n g process. I am s u g g e s t i n g t h a t t h e a b i l i t y t o a s s e s s a c t u a l r i s k s e x i s t s , and i t s h o u l d b e c o n s i d e r e d when ( 1 ) s e t t i n g r e g u l a t o r y r e q u i r e m e n t s , (2) when e s t a b l i s h i n g f a c i l i t y p e r f o r m a n c e s t a n d a r d s , o r ( 3 ) when d e f i n i n g r e m e d i a l a c t i v i t i e s . We f u l l y r e c o g n i z e t h a t many a r e a s o f u n c e r t a i n t y a r e c o n f r o n t e d when c o n d u c t i n g r i s k a s s e s s m e n t s . These i n c l u d e t h e l a c k of g e n e r a l l y accepted s p e c i f i c assessment techniques. Furthermore, e v e n when r i s k i s a s s e s s e d t h e r e i s a l a c k o f a c o n s e n s u s on the absolute l i m i t s of acceptable r i s k s . We do f e e l , h o w e v e r , t h a t t h e r e a r e s y s t e m a t i c a p p r o a c h e s t h a t c a n and a r e b e i n g u s e d and, a t t h e minimum, t h e y a r e d i r e c t i o n a l l y c o r r e c t and c a n s e r v e as a c o n c e p t u a l f r a m e w o r k f o r r e g u l a t o r y p r o g r a m d e v e l o p m e n t . S h e l l R i s k Assessment Procedure I w i l l o u t l i n e very b r i e f l y f o r you the g u i d e l i n e s , process and p r o c e d u r e s u s e d a t S h e l l f o r r i s k a s s e s s m e n t a n d r i s k r e s p o n s e ( 1 ) , ( 2 ) . I w i l l f o c u s my comments on how we a r e b e g i n n i n g to d e a l , f o r example, w i t h d e c i s i o n s c o n c e r n i n g t h e a c c e p t a b i l i t y o f o p e r a t i n g e x i s t i n g h a z a r d o u s w a s t e d i s p o s a l f a c i l i t i e s o r when c o n s i d e r i n g new w a s t e h a n d l i n g f a c i l i t i e s . The s t e p - w i s e e v a l u a t i o n and d e c i s i o n p r o c e s s c a n a l s o be u s e d i n a s s e s s i n g t h e e n v i r o n m e n t a l r i s k s p o s e d b y abandoned hazardous waste d i s p o s a l s i t e s . I w i l l a l s o b r i e f l y describe our e x p e r i e n c e w i t h a s i t e i n a s o u t h e r n C a l i f o r n i a community. Our R i s k A s s e s s m e n t P r o c e d u r e h a s grown o u t o f a c o n t i n u i n g n e e d t o d e a l w i t h b a l a n c i n g a l l t h e a s p e c t s o f h e a l t h and environmental r i s k s w i t h a l l other p e r t i n e n t elements i n our o i l and c h e m i c a l b u s i n e s s a c t i v i t i e s . The d e c i s i o n s we must make to d e a l a p p r o p r i a t e l y w i t h r i s k a r e n e c e s s a r i l y an i m p o r t a n t c o n s i d e r a t i o n i n pursuing our o v e r a l l business plan. I n many c a s e s , we must t a k e a c t i o n and make d e c i s i o n s p r i o r to r e g u l a t i o n s being issued which deal w i t h r i s k i n s p e c i f i c areas. By n e c e s s i t y t h e n , we need and u s e a s y s t e m t h a t r e f l e c t s o u r c o r p o r a t e e n v i r o n m e n t a l g o a l s and a l s o a l l o w s g u i d i n g t h e



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a l l o c a t i o n of the l i m i t e d resources a v a i l a b l e t o reach those goals. In a s e n s e , we c a n s a y we have d e v e l o p e d a s y s t e m t o a s s e s s e n v i r o n m e n t a l r i s k s i t u a t i o n s and a r e r e s p o n d i n g t o t h o s e a s s e s s ments w i t h d e c i s i o n s r e a c h e d i n a d e l i b e r a t e and d i s c i p l i n e d manner. The c o n f i d e n c e we have i n t h e s y s t e m i s b u i l t on t h e p r e m i s e t h a t we know i t i s d i r e c t i o n a l l y c o r r e c t w i t h i t s o v e r a l l o b j e c t i v e being t o reduce r i s k s . Moreover, t h e response d e c i s i o n s c a l l e d f o r i n t h e process r e s u l t from e v a l u a t i n g a l l t h e a v a i l a b l e s c i e n t i f i c information along with a l l the pertinent v a l u e s and j u d g m e n t s t h a t c a n be b r o u g h t t o b e a r . O v e r a l l , t h e major premise f o r our approach i s a d i r e c t i o n a l o r i e n t a t i o n t o w a r d r i s k r e d u c t i o n . The e v a l u a t i o n p r o c e d u r e used f o l l o w s a f o u r - s t e p p r o c e s s w h i c h c o n s i d e r s f i r s t Hazard I d e n t i f i c a t i o n ; second, Hazard E v a l u a t i o n ; t h i r d , R i s k E v a l u a t i o n ; and f o u r t h , R i s k R e s p o n s e . To a v o i d any m i s u n d e r s t a n d i n g o f t e r m s , t h e combined a c t i v i t i e s o f t h e f i r s t t h r e e s t e p s c a n be c o n s i d e r e d a s what i s commonly r e f e r r e d t o as m a k i n g a " R i s k A s s e s s m e n t . " The f o u r t h s t e p , R i s k R e s p o n s e , n e c e s s a r i l y must f o l l o w when t h e p r o c e s s i s used t o make p r a c t i c a l d e c i s i o n s . I w i l l now g i v e an o v e r v i e w d i s c u s s i o n i d e n t i f y i n g t h e g e n e r a l i n f o r m a t i o n needs and t h e s p e c i f i c d e c i s i o n s c a l l e d f o r a t e a c h s t e p . I w i l l u s e a s t h e example c a s e , e v a l u a t i n g a h a z a r d o u s waste d i s p o s a l s i t e . A l s o , I w i l l d i s c u s s the a p p l i c a t i o n of the p r o c e s s t o an a c t u a l s i t e b e i n g e v a l u a t e d i n C a l i f o r n i a . Hazard

Identification

As i s t y p i c a l i n r e g u l a t o r y m a t t e r s , u n d e r s t a n d i n g t h e d e f i n i t i o n s o f t h e terms used i s v e r y i m p o r t a n t . F i r s t , i n t h e b r o a d e s t s e n s e , h a z a r d means t h e p o t e n t i a l t o do harm, o r i n o t h e r w o r d s , t h e p o t e n t i a l t o c a u s e an a d v e r s e e f f e c t . In a waste d i s p o s a l s i t e e v a l u a t i o n , t h e hazard i d e n t i f i c a t i o n s t e p w i l l i n v o l v e c o l l e c t i n g and v a l i d a t i n g a l l r e c o r d e d and o t h e r i n f o r m a t i o n on t h e n a t u r e and p r o p e r t i e s o f t h e w a s t e s actually i n a site. The p u r p o s e i s t o d e t e r m i n e w h e t h e r a h a z a r d ous s i t u a t i o n a c t u a l l y e x i s t s . S t a t e d s i m p l y , jLs t h e r e a. p o t e n t i a l f o r harm t o h e a l t h and t h e e n v i r o n m e n t when c o n s i d e r i n g t h e materials present? The t y p e o f d a t a g a t h e r e d w i l l i n c l u d e a l l p e r t i n e n t i n f o r m a t i o n on (1) t h e i n v e n t o r y o f t h e w a s t e s d i s p o s e d o f a t t h e s i t e , (2) t h e c o m p o s i t i o n o f t h o s e w a s t e s , ( 3 ) t h e p h y s i c a l and c h e m i c a l p r o p e r t i e s s u c h a s p e r s i s t e n c e o f compounds and t h e i r s o l u b i l i t i e s , (4) t h e b i o l o g i c a l p r o p e r t i e s s u c h a s t o x i c i t y , and (5) t h e p o t e n t i a l i n t e r a c t i o n o f w a s t e s and d e g r a d a t i o n p r o d u c t s . The d e c i s i o n c a l l e d f o r a t t h i s p o i n t i n t h e p r o c e s s c e n t e r s on c o n f i r m i n g t h a t , f r o m t h e q u a l i t a t i v e d a t a g a t h e r e d , a p o t e n t i a l f o r an adverse e f f e c t has o r has n o t been i d e n t i f i e d . I f no hazard e x i s t s , f u r t h e r a c t i o n i s not warranted. I f the potential f o r an a d v e r s e e f f e c t i s e v i d e n t , t h e p r o c e s s r e q u i r e s p r o c e e d i n g t o t h e n e x t s t e p - H a z a rr d Evaluât iiocn . . -

American Cnemfca? Society Library 1155 St. N. w. Long and Schweitzer; Risk 16th Assessment at Hazardous Waste Sites ACS Symposium Series; American Chemical Washington, DC, 1982. Washington, D. C. Society: 20038

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Evaluation

The h a z a r d e v a l u a t i o n s t e p i n v o l v e s d e t e r m i n i n g t h e e x t e n t or scope o f t h e p o t e n t i a l adverse e f f e c t s from t h e hazards i d e n t i f i e d i n s t e p one. The e v a l u a t i o n e f f o r t now p r o g r e s s e s t o i n c l u d e a n a l y z i n g and d e s c r i b i n g b o t h q u a l i t a t i v e l y and q u a n t i t a t i v e l y t h e c h a r a c t e r i s t i c s w h i c h might cause t h e wastes t o be h a z a r d o u s and t o p r o v i d i n g t h e means f o r d e t e r m i n i n g i n s t e p t h r e e , t h e r i s k s i n v o l v e d under t h e d i s p o s a l c i r c u m s t a n c e s s p e c i f i c to the s i t e being studied. These means may i n c l u d e g a t h e r i n g p e r t i n e n t i n f o r m a t i o n f r o m l a b o r a t o r y and o t h e r s t u d i e s on t h e t o x i c o l o g i c a l p r o p e r t i e s of the array of c o n s t i t u e n t s i n the s i t e . A l s o p e r t i n e n t would be t h e range o f r e s p o n s e s t o t h o s e c o n s t i t u e n t s u n d e r t h e v a r i o u s s t a t e d , n o t a c t u a l , l e v e l s and t y p e s o f exposures along w i t h reviewing i n t e r - s p e c i e s t r a n s l a t i o n r e l a t i o n s h i p s and t h e means t o e x t r a p o l a t e t h e s e t o a c t u a l c o n d i t i o n s . W i t h t h e f o c u s on t h e a c t u a l q u a n t i t i e s o f w a s t e s i d e n t i f i e d i n t h e s i t e i n v e n t o r y , a p p r o p r i a t e f i e l d s a m p l i n g and a n a l y s i s must be u n d e r t a k e n t o v e r i f y t h a t t h e i d e n t i f i e d h a z a r d s a c t u a l l y exist. I f a h a z a r d h a s b e e n i d e n t i f i e d and t h e p o t e n t i a l f o r causing adverse e f f e c t s confirmed, a f t e r considering both the q u a l i t a t i v e and q u a n t i t a t i v e dimensions o f t h e s i t u a t i o n , t h e process r e q u i r e s proceeding to the next step - Risk E v a l u a t i o n . Risk

Evaluation

R i s k e v a l u a t i o n i n t h e a s s e s s m e n t p r o c e s s f o c u s e s on w e i g h i n g t h e h e a l t h and e n v i r o n m e n t a l t h r e a t s p o s e d b y a n i d e n t i f i e d h a z ard. F i r s t , t h e p o s s i b i l i t y and p r o b a b i l i t y t h a t a p e r s o n w i l l a c t u a l l y e x p e r i e n c e an adverse e f f e c t as a r e s u l t o f t h e e x i s t e n c e o f t h e e n v i r o n m e n t a l h a z a r d and e x p o s u r e t o i t must b e w e i g h e d ; and, s e c o n d l y , t h e number o f p e r s o n s who m i g h t be e x p o s e d must be considered. In t h e s t e p w i s e p r o c e s s , t h e r i s k e v a l u a t i o n combines t h e r e s u l t s o f t h e s e c o n d s t e p , h a z a r d e v a l u a t i o n , w i t h any i n f o r m a t i o n on a c t u a l e x p o s u r e p o s s i b i l i t i e s , i n c l u d i n g e v a l u a t i n g e x p o s u r e s o u r c e s , l e v e l s , f r e q u e n c i e s , t y p e s and r o u t e s . The a s s e s s ment e f f o r t i n v o l v e s i n t e r p r e t i n g t h e f i e l d v e r i f i e d d a t a f r o m t h e p e r s p e c t i v e o f d e t e r m i n i n g what t h e a c t u a l r i s k l e v e l t o humans and t h e e n v i r o n m e n t i s i n t h e r e a l w o r l d c i r c u m s t a n c e s p o s e d by the a c t i v i t y being evaluated. In t h e case o f a hazardous waste d i s p o s a l s i t e , the geoh y d r o l o g i c s e t t i n g c h a r a c t e r i s t i c s must now be c a r e f u l l y c o n s i d e r e d t o assess t h e e x i s t e n c e of subsurface exposure routes. A l s o , t h e p o t e n t i a l f o r e x p o s u r e f r o m a i r e m i s s i o n s and s u r f a c e r u n o f f must b e q u a n t i f i e d w h e r e p o s s i b l e . O v e r a l l , t h e s i g n i f i cant f a c t o r s would i n c l u d e : (1) e v a l u a t i n g t h e v o l a t i l i t y o f t h e w a s t e s w h i c h c o u l d l e a d t o s h o r t - and l o n g - t e r m e x p o s u r e t o a i r


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e m i s s i o n s , (2) c o n s i d e r i n g t h e l o n g - t e r m s o l u b i l i t y o f t h e w a s t e s i n w a t e r s f r o m e i t h e r r a i n f a l l o r s u r f a c e r u n o f f , (3) c o n s i d e r i n g t h e c o n t i n u i n g p o t e n t i a l f o r s u r f a c e w a t e r c o n t a c t , (4) r e v i e w i n g t h e r a i n f a l l r a t e s and r a i n f a l l f l o w p a t h s as t o t h e i r a b i l i t y t o s u p p o r t t h e i r c o n t r i b u t i o n t o c o n t i n u e d e x p o s u r e , (5) i d e n t i f y i n g t h e g r o u n d w a t e r c o n t a m i n a t i o n p o t e n t i a l and m i g r a t i o n p a t h s , (6) i d e n t i f y i n g g r o u n d w a t e r u s e s , and (7) a p p r a i s i n g p o p u l a t i o n e x p o s u r e by c o n s i d e r i n g p r o x i m i t y and number. I f t h e r i s k e v a l u a t i o n s t e p shows t h a t a s i g n i f i c a n t p o t e n t i a l f o r adverse e f f e c t s e x i s t s , the stepwise process c a l l s f o r d e v e l o p i n g an a p p r o p r i a t e r e s p o n s e . D e t e r m i n i n g t h e a p p r o p r i a t e ness of a response i m p l i e s having a b a s i s to vary the response. P r o v i d i n g t h a t b a s i s i s t h e end p r o d u c t o f t h e r i s k e v a l u a t i o n step. I t i n v o l v e s c l a s s i f y i n g t h e r i s k as b e i n g h i g h , low o r i n s i g n i f i c a n t so t h a t t h e a p p r o p r i a t e r e s p o n s e can be d e v e l o p e d . B e f o r e d i s c u s s i n g how r i s k s a r e c l a s s i f i e d , I w o u l d l i k e t o e m p h a s i z e t h a t t h e h a z a r d i d e n t i f i c a t i o n , h a z a r d e v a l u a t i o n , and r i s k e v a l u a t i o n s t e p s a r e p u r p o s e l y k e p t f r e e , as much as p o s s i b l e , of v a l u e judgments. Credible r i s k evaluations necessarily require u s i n g t h e b e s t s c i e n t i f i c i n p u t , t h e o r y , acumen and j u d g m e n t s . In t h e f o u r t h s t e p , v a l u e j u d g m e n t s come i n t o p l a y t o a s s i s t i n d e v e l o p i n g r i s k responses r e f l e c t i n g those s o c i e t a l judgments t h a t b e a r on t h e s i t u a t i o n b e i n g e v a l u a t e d . To c l a s s i f y r i s k s , a s y s t e m o r f r a m e w o r k f o r c l a s s i f i c a t i o n must be a g r e e d upon. I n a p e r f e c t w o r l d , a s o c i e t a l c o n s e n s u s on l e v e l s o f " r i s k a c c e p t a b i l i t y " w o u l d be a t hand and be s t r a i g h t f o r w a r d i n how i t w o u l d be a p p l i e d i n e a c h s i t u a t i o n b e i n g evaluated. However, i n t h e r e a l w o r l d t h e r e i s no c o n s e n s u s , and we c a n o n l y e v a l u a t e and t h e n d e f i n e t h e r a n g e s o f r i s k s p o s e d i n a c t u a l s i t u a t i o n s and t h e n j u d g e them f o r t h e i r a c c e p t a b i l i t y t o society. W i t h i n S h e l l , when t a k i n g a c t i o n s b e y o n d t h o s e r e q u i r e d by l a w , we use t h e c o n c e p t o f r i s k r e g i o n s o r r i s k c l a s s i f i c a t i o n s . The o b j e c t i v e o f our c l a s s i f i c a t i o n scheme i s t w o f o l d ; f i r s t , t o p r o v i d e guidance f o r the a l l o c a t i o n of resources such t h a t the most s e r i o u s r i s k s a r e h a n d l e d f i r s t ; and s e c o n d , t o i d e n t i f y t h o s e s i t u a t i o n s where a l l o c a t i n g r e s o u r c e s i s n o t w a r r a n t e d s i n c e t h e r i s k i s j u d g e d t o be i n s i g n i f i c a n t . Our s y s t e m , t h e r e f o r e , d i s t i n g u i s h e s t h r e e c l a s s i f i c a t i o n s o f risk: h i g h , low, and i n s i g n i f i c a n t . One m i g h t a r g u e t h a t a medium r i s k r e g i o n e x i s t s . A t t h i s t i m e , c o n s i d e r i n g a medium r i s k r e g i o n w o u l d o n l y add an u n r e a l i s t i c a u r a o f p r e c i s i o n t o t h e s y s t e m . We r e c o g n i z e d a t t h e o u t s e t t h a t t h e t o o l s a v a i l a b l e t o us i n our c l a s s i f i c a t i o n scheme a r e b l u n t . D e f i n i t i o n o f t h e b o u n d a r i e s between t h e r i s k r e g i o n s can be p r e c i s e by c h o i c e ; however, t h e r e a r e no e s t a b l i s h e d c r i t e r i a f o r b o u n d a r y s e t t i n g and, a t t h i s t i m e , o n l y g u i d e l i n e s f o r b o u n d a r y s e l e c t i o n can be o f f e r e d (1). The r a n g e o f c h o i c e s m i g h t i n c l u d e (1) r e a s o n a b l e p e r f o r m a n c e g o a l s f o r b e s t t e c h n o l o g y c o n t r o l equipment when a c t u a l e x p o s u r e l e v e l s f r o m e x i s t i n g f a c i l i t i e s i s


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a s s e s s e d , (2) t h e f e a s i b i l i t y o f c o n t r o l l i n g e x p o s u r e s , and (3) a d e s i r a b l e i n d u s t r y or a c t i v i t y performance g o a l . W h i l e the framework f o r r i s k r e g i o n s i s p r e c i s e , the u n c e r t a i n t i e s emerge when r e a l w o r l d i m p r e c i s e e v a l u a t i o n s o f r i s k r e c o g n i z i n g t h e b l u n t n e s s o f o u r t o o l s - a r e measured by t h e p r e c i s e y a r d s t i c k s . N e v e r t h e l e s s , when c o n s i d e r i n g r i s k c l a s s i f i c a t i o n s f r o m a s o c i e t a l v i e w p o i n t , one c a n h a v e c o n f i d e n c e and l o g i c a l l y c l a s s i f y h i g h r i s k r e g i o n s as b e i n g r e g i o n s o f " u n a c c e p table risk." The l o w r i s k r e g i o n m i g h t s i m i l a r l y be l a b e l e d as " v a r i o u s l y a c c e p t a b l e " w i t h t h e t h i r d r e g i o n r e f e r r e d t o as "insignificant risk." C o n s i s t e n t w i t h t h a t c l a s s i f i c a t i o n scheme, one c o u l d d e f i n e a p a r a l l e l s e r i e s o f a p p r o p r i a t e r e s p o n s e s . R i s k Response R i s k response i n v o l v e s a d d i t i o n a l d i f f i c u l t i e s . Defining r e s p o n s e s i n c l u d e s making comparisons w i t h o t h e r examples o f r i s k s s o c i e t y t a k e s , i n c l u d i n g t h e i r v i e w on t h e s e r i o u s n e s s o f t h e r i s k and t h e p e r c e i v e d b e n e f i t s f r o m t a k i n g t h a t r i s k . From t h e p r o c e s s o f c o m b i n i n g t h e s c i e n t i f i c i n f o r m a t i o n a v a i l a b l e w i t h t h e p e r t i n e n t v a l u e j u d g m e n t s , d e c i s i o n s c a n be made as t o what a c t i o n s a r e r e q u i r e d and j u s t i f i e d a s a p p r o p r i a t e r e s p o n s e t o the r i s k posed. When a r i s k a s s e s s m e n t shows a " h i g h r i s k " s i t u a t i o n , this w o u l d be j u d g e d u n a c c e p t a b l e and r e q u i r e a r e s p o n s e t o a b a t e t h e r i s k and move i t downward t o w a r d t h e "low r i s k " o r " v a r i o u s l y acceptable" region. S i m i l a r l y , an " i n s i g n i f i c a n t r i s k " c l a s s i f i c a t i o n i s j u d g e d as d e f i n i n g t h o s e s i t u a t i o n s w h i c h do n o t j u s t i f y o r w a r r a n t t h e a l l o c a t i o n o f r e s o u r c e s f o r f u r t h e r r i s k r e d u c t i o n . I must emphas i z e at t h i s p o i n t t h a t the " i n s i g n i f i c a n t " c l a s s i f i c a t i o n i s not e q u i v a l e n t t o an a b s o l u t e " z e r o r i s k . " The "low r i s k " o r " v a r i o u s l y a c c e p t a b l e " r e g i o n u n d e r t h i s l a b e l i n g scheme w o u l d t h e n , by d i f f e r e n c e b e t w e e n h i g h and i n s i g n i f i c a n t , i d e n t i f y t h o s e s i t u a t i o n s where b a l a n c i n g d e c i s i o n s w h i c h c o n s i d e r r i s k s , b e n e f i t s and j u s t i f i c a t i o n must be made f o r p r i o r i t i z i n g the a p p l i c a t i o n of c r i t i c a l r e s o u r c e s . The e x e r c i s e o f b a l a n c i n g r i s k s and b e n e f i t s i n t h e "low r i s k " r e g i o n i s c l e a r l y an a r e a w h e r e r e g u l a t o r y g u i d a n c e s h o u l d emphas i z e the importance of r e l a t i n g r i s k r e d u c t i o n t o c o s t s , b e n e f i t s and a l t e r n a t i v e r i s k s . T h i s "low r i s k " o r " v a r i o u s l y a c c e p t a b l e " r e g i o n i s t h e a r e a w h e r e c o s t s t o r e d u c e r i s k s h o u l d be j u s t i f i e d and a l t e r n a t i v e s c o n s i d e r e d . F o r j u s t as z e r o r i s k i s n o t g e n e r a l l y a t t a i n a b l e , v e r y l i t t l e r e a l p r o g r e s s toward our g o a l w o u l d be r e a c h e d i f we a t t e m p t e d t o s h i f t a l l " v a r i o u s l y a c c e p t a b l e " r i s k s downward. Regardless of the absence of a governmental p o l i c y e s t a b l i s h ing a b s o l u t e r i s k l i m i t s or boundaries of a c c e p t a b i l i t y , r i s k r e s p o n s e d e c i s i o n s must be made i n many i n d u s t r i a l s i t u a t i o n s . We have f o u n d t h a t c o u p l i n g d i s c i p l i n e d r i s k a s s e s s m e n t p r o c e d u r e s



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DREITH


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w i t h the r i s k region c l a s s i f i c a t i o n techniques y i e l d s appropriate r e s p o n s e a c t i o n s , and t h e p r o c e s s h a s p r o v e n t o be a p r a c t i c a l t o o l t o deal w i t h these i n h e r e n t l y imprecise situations. U s i n g t h e r i s k a s s e s s m e n t and c l a s s i f i c a t i o n a p p r o a c h i n e v a l u a t i n g waste d i s p o s a l s i t e s i t u a t i o n s should l i k e w i s e a l l o w m a k i n g p r a c t i c a l d e c i s i o n s by c o u p l i n g r i s k l e v e l s w i t h a p p r o p r i ate remedial responses. The s t e p w i s e d e c i s i o n p r o c e s s s h o u l d a l s o be u s e f u l i n e v a l u a t i n g t h e s c o p e o f r i s k s p o s e d by abandoned disposal sites. I f t h e r i s k assessment process leads t o t h e conc l u s i o n that a d i s p o s a l s i t e i s , indeed, posing a s i g n i f i c a n t t h r e a t t o h e a l t h o r t h e e n v i r o n m e n t , a p p r o p r i a t e l e v e l s and t y p e s o f r e s p o n s e s c a n be d e f i n e d . By c o n s i d e r i n g a l l t h e q u a n t i f i a b l e f a c t o r s , t h e i d e n t i f i e d u n c e r t a i n t i e s , and t h e g e o h y d r o l o g i c pred i c t i o n s and p r o j e c t i o n s s p e c i f i c t o e a c h s i t e , s u p p o r t a b l e p r a c t i c a l r e s p o n s e d e c i s i o n s c a n be made. I f a "high r i s k " c l a s s i f i c a t i o n i s supportable, the response a c t i o n to reduce that p a r t i c u l a r r i s k i s progressed without comparison t o other r i s k s . I f an " i n s i g n i f i c a n t r i s k " c l a s s i f i c a t i o n i s g i v e n , no a c t i o n i s r e q u i r e d s o l e l y t o reduce r i s k t o h e a l t h o r t h e environment. A circumstance worth mentioning a t t h i s point i s the response a p p r o p r i a t e t o d e a l w i t h n u i s a n c e and e s t h e t i c i s s u e s s u c h a s o d o r o r n o i s e when no h a z a r d c a n b e i d e n t i f i e d . A risk classification of " i n s i g n i f i c a n t , " w i t h respect t o h e a l t h o r the environment, w o u l d l i k e l y be s e l e c t e d and no r e s p o n s e j u s t i f i e d i n t h e c a s e o f a d i s p o s a l s i t e e v a l u a t i o n where o n l y o d o r i s t h e p r o b l e m . I n these i n s t a n c e s , a p p r o p r i a t e responses should be developed u s i n g a p r o c e s s w h i c h r e f l e c t s t h e e c o n o m i c , s o c i a l and p o l i t i c a l impacts o f t h e problem r a t h e r than t h e assessment process being d e s c r i b e d w h i c h has been developed t o d e a l w i t h h a z a r d s t o h e a l t h . I n d i s p o s a l s i t e s w i t h i d e n t i f i e d h a z a r d s , t h e more d i f f i c u l t and i n v o l v e d d e c i s i o n s w i l l h a v e t o be f a c e d when t h e c i r c u m stances r e s u l t i n s e l e c t i n g t h e "low r i s k " c l a s s i f i c a t i o n . Since t o t a l c o s t / b e n e f i t c o n s i d e r a t i o n s a p p r o p r i a t e l y come i n t o p l a y — f o r h e r e we hope t o a c h i e v e t h e g r e a t e s t r e d u c t i o n i n r i s k s f o r each d o l l a r spent — t h e response a c t i o n s can vary a c c o r d i n g l y . While r i s k reduction i s the o v e r a l l o b j e c t i v e , reducing the s e l e c ted r i s k l e v e l into the " i n s i g n i f i c a n t " c l a s s i f i c a t i o n i s not a u t o m a t i c a l l y t h e optimum s o l u t i o n s i n c e i t may r e q u i r e i n o r d i n a t e and e x c e s s i v e r e s o u r c e u t i l i z a t i o n . California

Site

Study

The e v a l u a t i o n o f an a c t u a l d i s p o s a l s i t e i n s o u t h e r n C a l i f o r n i a has been f o l l o w i n g a p a t t e r n o f e v e n t s t h a t , i n ways, f i t s t h e p r o c e s s I have b e e n d i s c u s s i n g . I would l i k e t o share w i t h you t h e h i g h l i g h t s o f t h i s e v a l u a t i o n . S h e l l i s one o f a number o f p a r t i c i p a n t s i n a n e f f o r t t o d e f i n e and r e s o l v e t h e p r o b l e m s p o s e d by a d i s p o s a l s i t e i n a n e s t a b l i s h e d community. The s i t e was p e r m i t t e d d u r i n g t h e 1 9 4 0 ' s , and u s e d f o r d i s p o s a l o f a c i d i c m a t e r i a l s f r o m p e t r o l e u m r e f i n eries i n the area. I t i s i n a developed r e s i d e n t i a l area.



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WASTE

SITES

As m i g h t be e x p e c t e d , when t h e s i t e was i d e n t i f i e d and some of t h e c i r c u m s t a n c e s s u r r o u n d i n g i t s past use were exposed i n t h e m e d i a , t h e r e a c t i o n o f many was t o e x p e c t a n i m m e d i a t e c l e a n - u p . R e l a t i n g t h i s r e a c t i o n t o t h e s t e p - w i s e p r o c e d u r e I have been d i s c u s s i n g , some jumped ahead t o s t e p f o u r - R i s k R e s p o n s e - and c a l l e d f o r an immediate e x c a v a t i o n w i t h o u t having c o n s i d e r e d s t e p s o n e , two o r t h r e e . C a l l i n g f o r immediate clean-up i s e q u i v a l e n t t o c l a s s i f y i n g t h e s i t u a t i o n a s one p o s i n g a h i g h r i s k . D o i n g s o c a n o n l y b e c o n j e c t u r e when o n l y l i m i t e d a n d q u a l i t a t i v e d a t a i s a t hand. T h i s r e a c t i o n was, o f c o u r s e , p r e m a t u r e and d i s r e g a r d e d c o m p l e t e l y s u c h f u n c t i o n s a s i d e n t i f y i n g and e v a l u a t ing the r i s k associated with excavation. A b e t t e r a p p r o a c h t o r e s o l v e community c o n c e r n i s t o move f o r w a r d and f o l l o w t h e s y s t e m a t i c p r o c e d u r e t o f i r s t i d e n t i f y t h e h a z a r d , e v a l u a t e i t s s c o p e , a s s e s s t h e r i s k s p o s e d , and t h e n d e v e l o p an a p p r o p r i a t e r e s p o n s e . At t h e C a l i f o r n i a s i t e , an e a r l y p r e l i m i n a r y e v a l u a t i o n by f e d e r a l , s t a t e , and l o c a l a g e n c i e s was made t o i d e n t i f y t h e n a t u r e o f t h e m a t e r i a l s i n t h e s i t e and t h e p o t e n t i a l f o r a n a d v e r s e effect. Then, w i t h i n d u s t r y p a r t i c i p a t i o n , a p l a n was f o l l o w e d t o d e v e l o p and t h e n i m p l e m e n t a d e t a i l e d and c o m p r e h e n s i v e s i t e evaluation. The d a t a f r o m t h e e v a l u a t i o n e f f o r t w i l l a l l o w m a k i n g a s u p p o r t a b l e d e c i s i o n on t h e h a z a r d s p o s e d by t h e s i t e . A l s o from t h e d a t a g a t h e r e d d u r i n g t h e s t u d y , p r e d i c t i o n s and p r o j e c t i o n s c a n be made a s t o t h e s c o p e o f b o t h t h e c u r r e n t and f u t u r e r i s k s p o s e d by the s i t e . I n a d d i t i o n , t h i s process w i l l provide i n f o r m a t i o n necessary to understand the r i s k s associated w i t h the s p e c i f i c r e m e d i a l measures a v a i l a b l e and under c o n s i d e r a t i o n . From c o n s u l t a t i o n s w i t h t h e a g e n c i e s i n v o l v e d , t h e community, and w i t h t h e i n d u s t r i a l p a r t i c i p a n t s , t h e r i s k s p o s e d b y t h e s i t e s h o u l d be c l a s s i f i a b l e and a p p r o p r i a t e r e s p o n s e and r e m e d i a l meas u r e s a g r e e d upon. We h a v e c o n f i d e n c e t h a t t h i s s c e n a r i o w i l l be f o l l o w e d t o reach a s a t i s f a c t o r y r e s o l u t i o n o f t h e problems associated with this site. Summary I t r u s t t h a t you w i l l agree t h a t t h e use o f a step-wise proc e s s f o r r i s k a s s e s s m e n t and r e s p o n s e d e v e l o p m e n t and t h e companion concept of using r i s k regions o r r i s k c l a s s i f i c a t i o n , o f f e r s a framework f o r p r a c t i c a l d e c i s i o n making. Making t h e e f f o r t a t t h i s time t o d e f i n e b o u n d a r i e s between h i g h , l o w and i n s i g n i f i c a n t r i s k s i n r i s k a s s e s s m e n t s i t u a t i o n s , i s n o t p r e e m p t i n g any u l t i m a t e s o c i e t a l j u d g e m e n t . Eventually governmental p o l i c y w i l l l i k e l y d e f i n e t h e r i s k boundary l i m i t s . I n t h e i n t e r i m , u s i n g s y s t e m s and a p p r o a c h e s t h a t a r e d i r e c t i o n a l l y o r i e n t e d t o reduce r i s k can serve as a base f o r e s t a b l i s h i n g the l o g i c a l framework t h a t f a c i l i t a t e s p r a c t i c a l d e c i s i o n making.


5.


DREITH

53

I t would appear t o be w o r t h w h i l e t o s u p p o r t e f f o r t s t o d e v e l o p r i s k a s s e s s m e n t a p p r o a c h e s a l o n g t h e l i n e s I have d i s c u s s e d r a t h e r t h a n j o i n a c o n s e n s u s s a y i n g t h a t i t c a n n o t b e done, or i n s u p p o r t i n g s e l e c t i n g m a t h e m a t i c a l models w h i c h a r b i t r a r i l y d e f i n e h a z a r d s and r i s k s . We s o l i c i t y o u r c o n s i d e r a t i o n i n d e v e l o p i n g a b r o a d e r c o n sensus which s u p p o r t s t h e premise t h a t a d e l i b e r a t e , d i s c i p l i n e d , s t e p w i s e approach t o making r i s k assessments i s a v a i l a b l e f o r practical application i n disposal s i t e evaluations.


Literature 1.

2.

Cited

P. F . D e i s l e r , " D e a l i n g w i t h I n d u s t r i a l Health R i s k s : A Stepw i s e , G o a l - o r i e n t e d Concept," Chapter 15, AAAS S p e c i a l Symposium #65, " R i s k in the T e c h n o l o g i c a l S o c i e t y , " Ed. by C. Hohenemser and J. Kaspreson, Westview P r e s s , B o u l d e r , CO, 1982. P. F . D e i s l e r , "A G o a l - o r i e n t e d Approach to Reducing Industrially-Related Carcinogenic Risks," Drug Metabolism Reviews Vol. 13, No. 5, Sept. 1982 - In P r e s s .

RECEIVED

June 16, 1982.


An Industry's Guidelines for Risk Assessment - ACS Symposium

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