When a heavy pall of smoke blanketed Melbourne last week, the Asthma Foundation assured sufferers of “the importance of planned burns for safety in our community [to] protect life, property and the environment by reducing the fuel levels”.

Across Victoria’s central highlands, if it didn’t sting your nostrils, the smoke obscuring the ranges might have passed for fog. Locals put up with it, mindful that planned burns are a necessary evil – remember Black Saturday.

But when Adam Menary – a resident of the Yarra Valley, east of Melbourne – awoke on successive days with headaches, he resolved to blow away “a smokescreen of spin”. Tertiary-educated in agricultural science, horticulture and forestry, Menary is a trained firefighter and director of a risk management company.

He and other researchers say most of the smoke in Melbourne was from industrial logging burns – not fire management. “We’re being misled by government spin,” he says. He’s among a cohort of scientists and business people urging the Victorian government to “come clean”.

One of these is Toolangi resident Deanne Eccles, vice-president of Tourism Network Yarra Valley. She says helicopters dropping aerial incendiaries – Country Fire Authority brigades call these “exploding ping-pong balls” – on logging coupes in Toolangi Forest are retraumatising Black Saturday survivors.

“These guys are generating extreme temperatures. The coupes burn for weeks, so when the winds pick up, I’ve got my family and my business in the middle of dry forest,” she says. “It makes me sick to the stomach. We feel so unsafe.”

Their yearly efforts to make this public, Menary says, have been stonewalled by “trolls in the logging industry”. But over the past two weeks, Greens MP Samantha Dunn put questions on notice to parliament. Addressing Environment Minister Lily D’Ambrosio, Dunn asked about “the smoke haze that has been blanketing the eastern suburbs for days now”.“Of those 119 planned burns,77 have been logging coupes, so this has nothing to do with community safety,” she said.

This week she asked Agriculture Minister Jaala Pulford why Victorians “must endure such poor air quality for the sake of the native forest industry?” Pulford replied that such a question falls under D’Ambrosio’s portfolio.

In a media release, Forest Fire Management Victoria (FFMV) chief fire officer Darrin McKenzie, a former timber industry figure, said he was sorry for the inconvenience but that without planned burns, “we won’t reduce bushfire risk”.

Chris Taylor, a research consultant who wrote his doctoral thesis on Australian forest certification standards, was the source of Dunn’s figures. He showed me how to verify them using a database of fire events on the FFMV website, cross-referencing them with 10-digit numbers of logging coupes. These and NASA satellite images make it clear that most of the smoke that affected Melbourne at the beginning of the month was from 119 Victorian central highlands and outer metropolitan burnoffs that Taylor calls “industrial events”. He says it is deceptive to describe these as “planned burns”, although technically true. “Logging fires aren’t there to protect life and property.”

Worse, the air near the coupes wasn’t monitored, but 41 kilometres downwind at Mooroolbark, an outer eastern suburb near the Dandenong Ranges, the readings were “off the scale” in toxicity, said a senior firefighter, who spoke on condition of anonymity. Clean air, in Environment Protection Authority Victoria’s air quality index, has a rating of 0–33; poor air 100–149. Very poor air is rated above 150. The Mooroolbark reading early on the first morning in May was 901 – toxic enough, my source said, “for emergency evacuation”. He said the air-quality index, an aggregate measure, hides more than it reveals: the devil is in the detail of particulates and gases.

Levels of dangerous carbon monoxide and P2.5 (carcinogenic particulates) were “through the roof”, he said. Later, Samantha Dunn told parliament the levels “greatly exceeded World Health Organisation” toxicity measures.

Logging coupes are on public land but are logged for private profit under regional forest agreements that exempt them from federal environment law. Most of the logged wood from a coupe is sold and pulped to make paper, but the remaining slash – woody debris that amounts to about 62 per cent of the timber harvest – is burned. In theory, burning the coupes after logging helps regenerate Mountain Ash forest.

VicForests, the state timber industry authority, assigns names to coupes: Warhead, Commando, Bone Crusher, Harpie, Ducks Guts, Troll, Dirty Days, Lucifer, Wicked, Mad Dog. Coupe burns cover a smaller area than fire-reduction burns, but incinerate at higher intensities and emit more pollution. On conservative estimates from government data, coupe fires burn “more than 140 tonnes per hectare” while fuel-reduction burns only “around 10 tonnes per hectare”, Chris Taylor says.

As the smoke descended on communities in the Yarra Valley, people reported its effects on Facebook. A woman had “eyes burning” and “bed sheets smelling like smoke”; another’s son “feels like he can’t breathe”. A man’s mother was hospitalised because she was “choking to death”, a teacher kept children indoors, a health clinic reported a rise in asthma attacks.

A spokesperson from the Department of Health and Human Services (DHHS) said there was only “a small amount of related cases”.

The Environment Protection Authority (EPA) received 200 complaints around the time of the smoke. By email, it advised a complainant that “smoke from logging does not fall into the EPA Victoria’s jurisdiction”. Determining where responsibility lies is tricky – I was shunted back and forth between VicForests, FFMV, the EPA and the DHHS.

While there is talk of a public inquiry, firefighter and forest campaigner Jill Redwood, who is based in rural East Gippsland, says class action against the “pyro-cowboys” in government “seems the only option left, because government agencies are as useless as tits on a bull”.

Deanne Eccles agrees: “The government is looking after the few – the timber industry elite. Tourists come here and are flabbergasted that we’re burning our forests.”

Farmers are also complaining about the smoke, as vineyards report “smoke taint” damaging high-value crops.

“This is a mass pollution event,” Redwood says. “A lot of farmers are in absolute despair.”

Whether for forest regeneration or fuel-reduction, the science supporting burns as a one-size-fits-all method is contested. Foresters who support logging practices tend to be cited by government agencies as definitive sources. These include industry staff and senior academics. Many, including retired forestry botanist Dr Peter Attiwill, have published with right-wing think tank the Institute of Public Affairs.

Attiwill authored a 2013 journal study “with help from VicForests” using data from across the state. He says his study showed “there’s absolutely no evidence whatsoever that forests managed for timber production are more fire-prone than forests in national parks”.

Opponents of current logging practices tend to be university-based ecologists and environmental impact modellers whose work is cited by conservation bodies.

One of these, the Australian National University’s Professor David Lindenmayer, is cited by both camps. His findings are qualified, allowing that forest types and fire behaviour are varied, and that it isn’t rigorous to generalise. Nonetheless, his studies show current logging of Victoria’s mountain ash forests – including the burning of coupes – increases the risk of bushfire, decreases the state’s water supply, and accelerates the demise of threatened species.

Last week, Lindenmayer and other scientists sent a letter to Premier Daniel Andrews. The five authors, from the University of Melbourne, the ANU and the University of Wollongong, urged the government not to rely on Attiwill’s claims. The letter cites subsequent studies showing the highest level of fire severity occurs in young regrowth forests.

Many scientists are urging VicForests to transition out of native forests and into plantation estates, which have higher annual yields and lower emissions from slash-burns. Late last year, a parliamentary inquiry recommended the same, but last month it emerged that VicForests is continuing to log against recommendations of the Victorian government’s flora and fauna scientific advisory committee.

Supply of mountain ash is in decline, and in 2016, PricewaterhouseCoopers estimated that each native forest industry job costs more than $5 million in state investment, and only brings 14 cents in return for every dollar spent.

Although it runs at a loss, VicForests operates as a business subsidising other industries. When the Heyfield sawmill faced closure, the government bought it for a reported $61 million following pressure from the then CFMEU, prompting six other mills to demand the same treatment. When Australian Paper – owned by Nippon Paper Group – owed VicForests $10 million, the government forgave its debt and legislated to give discounted timber to the Japanese company at a fixed price and fixed supply until 2030, in a move described by one industry figure as “an exercise in corporate socialism”.

“They’re poisoning Victorians’ air – and for what?” Jill Redwood says. “To line the pockets of Japanese shareholders.” She says official terms such as “fuel reduction” and “fire management” are deceptive “bafflegab” that reduces forests to commodities.

Adam Menary, who last week raised these concerns at an EPA Victoria air pollution “source apportionment” workshop, says that while some government agencies are “failing in their duty of care”, others are at least promising to listen. At the workshop, Lily D’Ambrosio invited submissions for a “Clean Air For All Victorians” campaign. “Today,” she said, “kicks off engagement with Victorians about priorities for what our future air quality should be.”