Velsicol knows the dangers of handling HCCPD and therefore requires its buyers to go through a strict review and educational program on the storage, use and disposal of the chemical.

The company also provides safety data sheets and a handling guide on its website, and delivers the chemical to purchasers all over the world.

[7] In addition, Hexachlorocyclopentadiene readily undergoes the Diels-Alder reaction to give a variety of adducts that were commercialized as pesticides.

Most of these pesticides are no longer commercially available and banned by the Stockholm Convention on Persistent Organic Pollutants due to their toxicity to humans and animals.

These may undergo ring-opening hydrolysis to form pentachloro-cis-2,4-pentadienoic acid, which decarboxylates to cis- and trans- pentachlorobutadiene, though this is only a minor pathway.

For multiple oral exposures in rats, steady state concentrations ranged were achieved in 10 to 30 days.

This might then explain why HCCPD causes effects at the point of contact for all the possible routes of exposure, in addition to the tissue-binding properties.

A small percentage of wastewater treatment workers who were exposed to water containing HCCPD in 1977 reported irritation of skin and eyes, chest discomfort, headaches, nausea and fatigue.

In the long term, they showed irregularities in their liver function using tests that monitor enzyme levels.

[12] Other proposed parameters for characterizing effects in humans, like urinary porphyrin excretion, were also tested for their potential use as a biomarker, but none were deemed significant enough.

In their development there are critical periods where distinct structures and functions can be more susceptible towards disruption, and the damage done might only become apparent in a later stage of life.

Absorption may differ for children because of their incompletely developed organs and larger surface to body weight ratio.

Fortunately, it is very unlikely that small children are immediately exposed to HCCPD because it is only found as an impurity in pesticides and is not used in homes.

In order to see degenerative brain effects in for example rats, the animals are exposed to a high dose of  HCCPD concentration by inhalation.

However, as the compound was not entirely pure (93.3%) while performing studies, some of the toxic effects could be attributed to the impurities, especially at high doses.

Single high doses of HCCPD resulted in increased effort to breathe in rats and rabbits alike.

Also, these rats and rabbits experienced diarrhea after single oral dosages of HCCPD, and showed acute necrotic lesions in the forestomach.

In repeated exposure experiments on rats and mice inflammation and epithelial hyperplasia of the forestomach were observed.

Body weight was heavily affected after oral ingestion of HCCPD by rats, more severely for males than females.

Lung effects of rabbits were examined in dermal animal studies, showing congested blood and fluid by exposure of HCCPD (93,3% pure, so again a possibility of contaminant interference).

When some of them sought medical attention, it was determined the plant was contaminated with HCCPD, and numerous tests were performed to document these circumstances.

Approximately one fifth of waste water treatment workers reported having nausea and abdominal cramps after exposure for a period between 3 and 15 days.

Chronic exposure of HCCPD at very low concentrations produced a yellow-brown pigment in the lung, tracheal and nasal epithelium in rats and mice.

For acute high exposures (1 hour, 42 ppm) all animals died, after showing difficulty breathing and gasping for air.

The HCCPD chemical family quickly attracted increased attention with the discovery of its insecticidal properties in 1955 and extensive commercialization.

However, due to extensive use, the HCCPD family of insecticides (chlordane, aldrin, dieldrin, endrin, heptachlor) became less effective as a result of genetic mutations of the targeted insects.

This flame retardant was used in polyolefins and Nylon and also in wires and cables, due to its good moisture resistance.

However, given that HCCPD is a versatile raw material for the synthesis of a wide range of end products, as of October 2021 it is still available commercially.