As firemen doused the toxic embers and smouldering sludge from a major chemical fire and explosion at a pesticide warehouse, questions about the lack of communication remained unanswered.
What are the short- and long-term health risks to Durban residents - be they babies, elderly, sick or healthy - who have been inhaling toxic pesticide and solvent fumes for more than a week following the arson attack on the United Phosphorus Limited (UPL) warehouse in Cornubia? Should the most vulnerable people have been warned much sooner, or advised to consider evacuating their homes?
Why did it take the Mumbai-based pesticide group and government authorities more than five days to issue an initial statement about the potentially serious health risks? Was the warehouse designed to safely contain toxic and hazardous chemicals next to nearby residential areas in the event of accidental fires, arson or other natural disasters?
Judging by the number of dead fish, crayfish and other water creatures washing up on the banks of local rivers and beaches north of Durban over the past few days, there were clearly major shortfalls in the pollution prevention measures at the new UPL warehouse.
Though the company has belatedly published the names of some of the chemicals that were stored at the warehouse, it has not made the full list publicly available or given any indication of the total volume of poisonous products that went up in flames following an arson attack on the night of 12 July.
However, a list of agro-chemical products marketed on the UPL South Africa website has set alarm bells ringing among health and environmental watchdog groups because several are banned or severely restricted in the European Union and in other nations owing to scientific studies demonstrating serious public health or ecological risks.
These include glyphosate, classified in 2015 as a likely cause of cancer in humans and animals following an evaluation by the United Nations expert advisory group, the International Agency for Research on Cancer. Other chemical nasties marketed by UPL South Africa include 2.4-D, paraquat, carbofurans, chlorpyrifos and atrazine.
Because the health impacts of some of these products are largely based on long-term human exposure studies or animal laboratory experiments, the immediate and latent impacts of shorter, airborne exposure remain unclear.
The Indian multinational company, which boasts that it is the world's fifth-biggest agro-chemical group, insisted this week that it had been advised that "there is a minimal risk of any long-terms [sic] effects to the health of people exposed to smoke from the warehouse".
This was based on advice from pesticides industry consultant Gerhard Verdoorn, director of the Griffon Poison Information Centre. However, the University of KwaZulu-Natal's head of occupational and environmental health, Rajen Naidoo, was among the signatories of an unofficial public health warning issued on 20 July that warned: "As far as is possible, stay indoors as much as you can, with windows closed, particularly if your home is in the direction of the chemical plume. If you, your child, or elderly people with chronic chest and heart disease live in the area of the smoke, and it is at all possible to stay with relatives outside the area for the next few days, then it is advisable to do so."
The UPL chemical storage facility, which opened its doors only four months ago, is located in the new Cornubia "mixed-use" - residential, retail and light industrial - property development zone. The site is surrounded by high-,middle- and low-income residential areas that include Umhlanga, Waterloo, Blackburn, Cornubia, Prestondale, Mt Edgecombe, Sunningdale and Glen Anil.
Depending on changing wind directions, fumes have also spread much further afield. Despite initial public assurances from UPL that there is no cause for undue panic, environmental epidemiologist Rico Euripidou has sounded a more cautious note and also criticised the belated responses and apparent failure of government health authorities and regulators to keep the public fully informed about the potentially serious health risks.
Euripidou, an environmental health campaigner for the groundWork watchdog group, has expressed concern about government officials and regulators' long delay in spelling out the precise dangers and commissioning independent toxicology experts to undertake monitoring and evaluation studies.
"Where are the notices on the beaches warning people not to collect dead fish from the beach? Where are the messages on radio stations, especially for poorer communities who do not have access to the internet, if there is a need for them to leave their areas because of poisonous plumes of air?" he asked.
For its part, UPL said in a statement this week that "exposure in the short term to some of the chemicals contained in the crop solution products may result in dermal, eye and respiratory irritation. The situation is being closely monitored and to date, no cases of acute human toxicity have been reported."
All the same, the experience of thousands of victims of previous deadly gas leak disasters in Bhopal, India, in 1984 and Seveso, Italy, in 1976 provide a manifest warning about the dire human health and environmental risks when hazardous chemical facilities unexpectedly go "boom in the night".