Flow Hive - Is There A Problem With Plastic?

The 'Flow Hive' is a type of bee hive designed to make the extraction of honey easier and simpler, and in effect, is a Langstroth super with an extractor attached.

Is the flow hive ethical?

There is one major issue that seems to unite many beekeepers:  plastic in the hive.  At a time when effort is being made to improve honey bee health, many beekeepers are paying taking extra care over the materials used in and around the hive.  For example, a tin of Cuprinol may be handy in the garage, but it's not great for painting your bee hives with.

The same goes with Creosote.

Aside from this, it probably depends in part, on your reasons for wanting to get into beekeeping in the first place, and your view of honey bees.  There could be a myriad views on the subject, many of them sparking heated debate.  

Here are two extremes: 
If your primary purpose in keeping bees is not the harvesting of honey, but the nurturing of the bees or pollination service, the flow hive is unlikely to appeal to you. 

If you think honey bees are a creature to be exploited, then you may be rubbing your hands with glee at the thought of honey on tap.

Why plastic in the hive is a problem

Let's for one moment, ignore the problem of plastic in the wider environment, which is already of grave concern, and consider the impact of plastic on the bees.

Much of the concern around plastics (other than general environmental issues) tends to revolve around:

  • Worry about BPAs (see below);
  • It's better for the health of bees to make their own combs;
  • Chemical leaching from the plastic super even into natural combs;
  • General preference for natural, breathable materials.

Is the Flow Hive BPA free?

The manufacturers state that the flow hive is BPA (Bisphenol A) free.   This is relevant because BPA is known to leach out of the the plastic.   This must surely be problematical in a hive.  Even in humans, there are concerns that BPA can cause serious health issues2.

So what is the plastic in a flow hive?  The manufacturers state that it is virgin food grade polypropylene, which is indeed BPA free. 

What is virgin food grade polypropylene, and is this plastic safe for bees?

Polypropylene is currently approved by the FDA for use with food packaging and storage.  This may imply the plastic is safe for bees, but I could not find any specific research in this area.

However, a study from 2019 investigated the toxicity of a variety of plastics (34 plastic products) with four or five items per polymer type1.  

They found that toxicity is less prevalent in food contact plastics, but not absent, and that plastic toxicity, even by type, can vary.  This variation may be down to differing methods of manufacture.    

Furthermore, they proposed that the toxicity of Polypropylene (and some other plastics) depends on their individual chemical composition, which remains unknown to the public, although in the case of Polypropylene, it had lower levels of toxicity than some of the other plastics tested.

Of course bee bodies are smaller than human bodies, their comb and larvae would be in close proximity to the plastic at all times.  Is this relevant?  

I decided to include more information about the study so that readers can make up their own mind as to whether or not they are happy for this plastic to be present in their hives, and if necessary, can conduct further research.

Safe for bee hives?  A chemical analysis of polypropylene

The plastics were purchased from retail sources (i.e. readily available to consumers) and wherever possible, packaging was included, and 20 of the samples had food contact.  

Polypropylene was one of the plastics assessed, and 5 samples were used, including:

  • Polypropylene plastic from a refillable drinking bottle,
  • Polypropylene yogurt cup 
  • gummy candy Polypropylene packaging 
  • handkerchief Polypropylene packaging 
  • Polypropylene shampoo bottle.

I have extracted key data and present it in table form below.

Baseline toxicityThe baseline toxicity varied with the product.
Oxidative Stress Response*Two of the five Polypropylene samples
induced an oxidative stress response.
Endocrine Activity.One Polypropylene sample was
CytotoxicityTwo Polypropylene samples were cytotoxic
in the Yeast Antiandrogen Screen**.
Comparison of Food and
Non-food Contact Materials
A high toxicity for specific food contact
articles for 2 of the 5 Polypropylene samples:
gummy candy packaging, and yogurt cup
Presence Of High Priority Chemicals
In the 5 Polypropylene samples,
the following were detected:

Benzophenone - 1 sample;
Butylated hydroxytoluene - 2 samples;
1-decanol, 2-hexyl- - 1 sample;
Tributyl acetylcitrate - 2 samples;
Lilial - 2 samples.

Oxidative stress is an imbalance of free radicals and antioxidants in the body, which can lead to cell and tissue damage.

** See Yeast estrogen screen (YES) and Yeast androgen screen (YAS).

Other plastics assessed in the study:

  • polyvinyl chloride (PVC) 
  • polyurethane (PUR) 
  • polyethylene terephthalate (PET) 
  • polyethylene (HDPE) and  (LDPE)
  • polylactic acid (PLA). 
  • polystyrene (PS).


It would be interesting to see whether the same scientists who conducted the research above, would be prepared to conduct research investigating chemical leakage from Polypropylene into hive products, and likewise, potential effects on bees could be a subject of further research.


1. Benchmarking the in Vitro Toxicity and Chemical Composition of Plastic Consumer ProductsLisa Zimmermann, Georg Dierkes, Thomas A. Ternes, Carolin Völker, and Martin WagnerEnvironmental Science & Technology 2019 53 (19), 11467-11477DOI: 10.1021/acs.est.9b02293

2. 'What is BPA, and what are the concerns about BPA?' - Mayo Clinic. - Brent Bauer M.D.; May 14, 2021.