The following case studies are provided to give you experience in completing risk assessments. These studies allow you to identify the process that one goes through in risk assessments. (This implies, “This is what the case study tells me, this is what I need to know, this is what I would do with the information once it is determined…Perhaps you should start out saying, “The first step I took…) The whole point of this process is to get you familiar with the components of the risk assessment process and to give you practice with trying to find the different components and then put them together to make conclusions.
The final project has you actually doing the process for a particular toxicant with you researching for the information you need.
FIRST THING: Also, though more important for stage 2, you will need to determine why you are doing the risk assessment. In an accident case it might be to determine what the long-term health effects will be to those who were exposed but survived. It might be to determine how high the risks of exposure are to nearby residents, or if exposure were to happen, what the risks to them might be. In a workplace case the risk assessment might be to determine to what level the clean-up (of air, water, etc.) should be to protect human health. It might be to determine if any workplace accommodations need to be made. In a medically related case the risk assessment might be to characterize the risks to workers associated with a medically related accident or incident. Its purpose might be to determine the risks to the general public from an incident. If you narrow down your focus it will make how you go about dose response investigation and exposure assessment more straightforward.
Staged Project, Stage 2: Exposure assessment and dose-response assessment. Based on the case studies below and the hazard identified, discuss how you would approach an exposure assessment and a dose-response assessment.
NOTE: not all of these case studies are real incidences. You have been given choices so that you may explore areas within your interests.
Choose ONE study from EACH AREA below (this means you will comment on THREE case studies – one from community-based, one from work-based and one from medically based.
Community-Based Hazard Exposure:
Choose one (1) of these –
http://www.ops.fhwa.dot.gov/publications/fhwahop08014/case4_0.htm Case study, Chlorine Release in South Carolina.
http://www.uic.edu/classes/eohs/eohs400/cases/risk/case.html#Case%20Study water pollution by manufacturing plant.
Workplace-Based Hazard Exposure:
Choose one (1) of these –
A: An employee developed occupational asthma after working for a large multi-national company in Gloucester. He was employed between 1995 and 2004 as a solderer and was exposed to rosin based (colophony) solder fume during his career. The company had no fume extraction equipment to remove rosin based fumes from the workroom air or from the breathing zones of its solderers.
His health was deteriorating from 1999 onwards and he was taking time off work due to breathing difficulties.
B: Jenkins Chemical
Jenkins Chemicals is a small/medium size specialist chemical manufacturing
company based in Hartfordshire, England. The company supplies Hydrazine Hydrate (a known carcinogen) for use as an oxygen scavenger of boiler feed water, preventing corrosion damage in high pressure boilers used in the power generating industries and used as a chemical intermediate for a number of different applications. Under the Chemicals (Hazard Information and Packaging for Supply) Regulations, Hydrazine Hydrate is a Category 2 carcinogen – believed to cause cancer in humans. Whilst under the EU Classification Labeling and Packaging regulations it will carry a category 1B (H350) Carcinogen classification.
The company originally used a manual operation to decant the Hydrazine Hydrate
into storage tanks using a hose and lance system. A similar approach was used to
prepare Hydrazine Hydrate for supply to customers; manual decanting into
containers of various sizes up to 1 tonne intermediate bulk containers. When HSE inspected the site and assessed both processes, HSE and the company agreed that there was a heavy reliance on both personal protective equipment (PPE) and Respiratory Protective equipment (RPE). The company also had a local exhaust
ventilation system on site which would only remove escaping vapors when near the
source of exposure, therefore offering a limited level of protection. This was important
given that the company had discovered that airborne exposure concentrations during
manual transfers were in excess of the assigned regulatory exposure limit for
Hydrazine, although no employee was know n to be exposed to hydrazine vapor
above the regulatory limits.
Substitution – using a less harmful chemical with similar properties was not a viable
option for the company as there was no other practicable alternative oxygen
scavenger for use in high pressure boilers. Overall, the potential for worker exposure coupled with a heavy reliance on PPE raised concerns for both HSE and the company.
At the heart of the shared dilemma was the need to minimize the potential for worker
exposure to a vital, but harmful chemical.
Jennifer is a nulliparous, 30-year-old healthy woman who presents to your office for her annual well-woman exam. She was recently married and is contemplating pregnancy within the next year. She has no complaints except for occasional headaches, which occur sometimes at work but never on weekends.
Jennifer has worked as a lab technician at a local polymer manufacturer for the past 6 years. She is concerned about possible chemical exposure at work. For protective equipment she uses eye protection, an apron, and latex gloves. There is no ventilation hood in the lab. The primary chemical she works with is N-methylpyrrolidone (NMP), a chemical used to dissolve a wide range of other chemicals. She is exposed to NMP on a weekly, and often daily, basis.
Jennifer’s exam is normal. The pregnancy test that you order is negative. You pull up the material safety data sheet (MSDS) for NMP online, which you review with Jennifer. The MSDS mentions no adverse reproductive effects, and Jennifer is relieved. However, knowing that MSDS entries are often incomplete and inaccurate with regard to information on the reproductive effects of the chemical, you investigate NMP in more detail on the Internet. You learn that in 2001, NMP was listed as a known reproductive toxicant in the state of California on the basis of animal studies.6 You search the developmental and reproductive toxicology database at the TOXNET Web site and find several entries, including a case of a pregnancy loss in a lab technician exposed to NMP.
On the basis of the information from the Internet and the toxicology database, you refer Jennifer to an occupational health specialist. You receive a note from the specialist after Jennifer’s consultation. She has recommended the use of additional safety precautions at Jennifer’s workplace, including a ventilator hood, a well-fitted respirator, neoprene rather than latex gloves (the former are more resistant), and continued use of the apron and eye protection.
The occupational health specialist asks you to explore with Jennifer the options for transferring out of the lab to a less toxic work environment, bearing in mind her legal rights and the potential for job loss or discrimination. You write a letter to Jennifer’s employer identifying NMP as a potential reproductive toxicant, highlighting the importance of avoiding reproductive toxicants, and the need to transfer Jennifer to a job without such exposure while she is trying to get pregnant and during pregnancy.
The employer transfers Jennifer to a position with less toxic exposure and invests in additional safety equipment for Jennifer and other employees. Had no other jobs been available, Jennifer might have decided to continue in the same job with improved protection. After the transfer, Jennifer’s headaches resolve.
This case illustrates that exposures to reproductive toxicants can occur at the workplace. With understanding and appropriate information, health care providers can advocate for their patients and make specific workplace recommendations that reduce the risk of exposure to reproductive toxicants.
*Case study adapted from GENERATIONS AT RISK: REPRODUCTIVE HEALTH AND THE ENVIRONMENT, published by The MIT Press.7
Medically Related Exposures:
Choose one (1):
Case A: Jan was a nurse at the Lydecker Hospital in Minneapolis, MN. She worked the night shift in the communicable diseases ward.
One evening a 28 year old male (Jason) was brought to the ward in a confused condition. His chart indicated that he had AIDS and hepatitis C and was presently recovering from acute alcohol poisoning.
Toward the end of her shift Jan was doing patient assessment. Upon entering Jason’s room Jan approached the bed to determine Jason’s vitals (blood pressure, temperature, etc.). Upon waking Jason became extremely agitated, verbally and then physically abusive. Jan, in an attempt to calm the patient, gently put her hand on his shoulder, which he then grabbed and proceeded to bite Jan several times, drawing blood and requiring 36 stitches. It was also determined that Jason bit his own tongue in the process exposing Jan to blood-borne pathogens as well as saliva transmitted pathogens in the process. Assess the medical situation Jan is in.
Case B: Jacob works as an infectious disease analyst at a local hospital. While he is a physician, his job is largely administrative in that he analyzes data on suspected nosocomial (hospital induced) infections. He notes that beginning the third week in March that three patients developed pneumonia after being in the hospital between 5-7 days. Both were immunologically compromised. Two patients developed surgical site infections. During the fourth week in March he noted that two nurses had come down with pneumonia and one had come down with a skin condition. Suspecting MRSA (Methicillin Resistant Staphylococcus Aureus) a full evaluation of hospital protocol was initiated. It was found that the all patients to have come down with MRSA related illnesses been interviewed by the same intake personnel. All nurses who had become ill had attended the ill patients. It was later determined that the intake person was a carrier of MRSA. What is the risk for other patients and personnel in the hospital?