Healthcare Drain Disposal: A cost-savings, but at what cost?

“My formalin, buffer, and reagents can get dumped down the drain, right?”

Lab technicians at hospitals ask me this question all the time. I’m always reluctant to answer the question immediately, because the answer isn’t usually a simple “yes” or “no” question. It’s not just a question of “what’s legal?”. Sometimes it’s a question of “what’s safe?” or “what’s ethical?”. What follows in an anecdote that illustrates my point.

The other day I was taking an inventory of healthcare client’s stock chemicals and I came across a peculiar product. The product was inconspicuously labeled by the manufacturer as a “concentrated wash buffer”, and in speaking with my client’s lab staff I discovered that this liquid material is processed in large quantities on a daily basis in an immunoassay and clinical chemistry testing procedure. The lab analyzers which process this material are plumbed to discharge this wash buffer into the municipal sewer.

When I saw that the analyzers were piped directly into a floor drain I took it upon myself to investigate further. I asked technicians in the area about the analyzers and why they were piped directly to the drain. I could have predicted the response:

“It’s just buffers and reagents. That can go down the drain, right?”

I suppressed a response and asked for permission to use a computer with an internet browser. I used the product label to locate a copy of the MSDS for this material online. When I reviewed the MSDS I noted that the product listed the following materials as constituents:

98.91% - Mixture of chemical and/or biological substances for in vitro diagnostic use.

00.90% - Sodium azide

00.19% - 1,2-propylene glycol

Okay, so this material isn’t considered an EPA hazardous waste based on these constituents. So you can dump it down the drain, right? Not so fast! Consider this language which was pulled from multiple sections of the same document:

• “Prevent liquid and vapor from entering sewage system, storm drains, surface waters, and soil.”
• “Do not discharge to storm drains or sewage system.”
• “Harmful to aquatic organisms, may cause long-term adverse effects in the aquatic environment”
• “Do not allow product to reach ground water, water course, or sewage system.”
• “Flush drains thoroughly with water to prevent the formation of potentially explosive metal azides in plumbing, if product and/or instrument waste is released to a drain.”

I have visited clinical laboratories at many hospitals and I have spoken with many laboratory technicians who work with analyzers that are piped directly to drains. Often times I will hear lab staff defend their drain disposal practices after they have read only a portion of the MSDS. Consider the example I have described above. Does the last bullet point above provide justification for sewer disposal? If you read carefully, you will discover that the sentence is carefully worded by the manufacturer. The key word is “if”. This manufacturer does not endorse drain disposal in this document, and in fact, they have gone to great lengths in other sections of the document to discourage drain disposal.

You don’t have to be an environmentalist to appreciate the serious consequence associated with discharging harmful materials into sewer systems. Our society thinks of its hospitals as stewards of public health. Public health and the health of the environment are fundamentally and directly linked. A hospital that makes unwise decisions about its sewer discharge policies is at risk of violating the public’s trust and contradicting its very purpose: to ensure that people are healthy.

Bottom line: if you are a lab technician or EH&S administrator at a hospital I encourage you to carefully evaluate and periodically reevaluate decisions to discharge lab waste into your community’s sewer system.