Pharmaceutical Units: Solvent Emissions and Waste Rules

A pharmaceutical unit needs State Board consent under the Air and Water Acts, and bulk drug and intermediate manufacturers also need prior environmental clearance under the EIA Notification 2006. Solvent vapours from reactors, centrifuges, dryers and storage tanks must be captured through condensers, scrubbers and other controls set in the consent. Spent solvents, distillation residues, spent carbon and process waste are hazardous waste: they need authorisation, safe storage, manifests for every load and disposal only through authorised recyclers or facilities. Most legal trouble starts where solvent goes missing from the books.

This guide is for owners, plant heads and EHS managers of bulk drug (API), intermediate and formulation units, and for residents who live beside a pharmaceutical cluster and want to know what the units are supposed to be doing. It covers solvent emissions, hazardous waste, effluent, the paperwork inspectors ask for, and the risks that most often lead to closure directions and compensation.

For help with consents, clearance conditions, notices or a complaint against a unit, our industrial air pollution lawyers work with pharma units and with the communities around them.

The essentials

What pollution rules apply to a pharmaceutical unit?

Every pharmaceutical manufacturing unit needs consent to establish and consent to operate from the State Pollution Control Board, under section 21 of the Air Act and section 25 of the Water Act. The consent sets the products and capacity, the solvents and fuels allowed, the air pollution controls on each vent and stack, the effluent treatment and discharge conditions, and the waste conditions. Running beyond the consented products or capacity is treated as running without consent.

Bulk drug and intermediate manufacturing, which involves chemical synthesis, falls within the EIA Notification 2006 as a synthetic organic chemicals activity, so it needs prior environmental clearance, appraised at the central or state level depending on location and other factors in the schedule. Formulation units, which only mix, granulate, tablet or fill finished medicines, generally do not need clearance but still need consent. Expanding capacity or adding new products to a bulk drug unit normally needs an amendment of the clearance first.

On top of these, the Hazardous and Other Wastes Rules 2016 govern spent solvents, residues and other wastes, and the CPCB and State Boards have issued sector directions on effluent and emissions that are written into consents. The product mix in a pharma unit changes often, so the gap between what the consent says and what the plant actually makes is where many units get caught.

How the rules differ for bulk drug and formulation units

Most legal risk sits with synthesis plants, but formulation units are not exempt. Check your own consent for the details.

Where solvent emissions come from in a pharma plant

Solvents such as methanol, toluene, acetone, dichloromethane and others are used in large quantities in synthesis and purification, and they evaporate easily. Vapour escapes from reactor vents during charging, heating and distillation, from centrifuges and filters when wet cake is unloaded, from dryers, from receivers and storage tanks as they fill and breathe, from drum handling and tanker unloading, and from the open surfaces of effluent tanks if solvent reaches the drain.

The controls usually written into consents follow from those sources: condensers on reactor and distillation vents, often with chilled brine, so vapour is turned back to liquid and recovered; scrubbers for acid or alkaline gases released by reactions; closed transfer systems and nitrogen blanketing; vent condensers or vapour return on storage tanks; and adsorption or incineration for the residual stream in some plants. A well-run plant recovers most of its solvent and loses little to air.

When these controls are missing or poorly maintained, the result is lost money for the unit and a constant chemical smell for the neighbourhood. It also creates a gap in the solvent accounts, which is where inspectors and NGT committees have increasingly begun to look.

Acid gases, dust and odour: the other air issues in pharma units

Solvent vapour is not the only air problem. Many synthesis steps release acid or alkaline gases such as hydrogen chloride, sulphur dioxide or ammonia, which is why scrubbers on process vents are a standard consent condition. A scrubber only works if the scrubbing liquid is changed and its strength checked; a scrubber running on spent liquor is a scrubber in name only, and the logbook will show it.

Formulation units have a different profile. Their main air issue is fine powder from dispensing, granulation, compression and coating, controlled by dust extraction and filters, along with emissions from the boiler and DG sets. Both kinds of unit can produce strong odours, from solvents, from sulphur compounds in some reactions, or from an overloaded effluent plant, and odour is the complaint neighbours raise first. Treating odour as a symptom and tracing it to its source inside the plant is usually cheaper than arguing about it with the board.

The legal framework for pharma pollution

Which pharma wastes are hazardous, and what the rules require

In a synthesis plant, most process waste is hazardous under the 2016 Rules: spent solvents that cannot be reused in-house, distillation residues and still bottoms, spent activated carbon, spent catalysts, process residues and off-specification batches, salts and sludge from evaporators and the effluent plant, and discarded containers that held hazardous chemicals. Formulation units generate smaller quantities, mainly rejected or expired products and contaminated packaging.

The unit must hold an authorisation from the State Board listing each waste stream and its quantity, store waste in a designated, covered and labelled area within the limits allowed, and send it only through authorised transporters to an authorised facility. That can be a treatment, storage and disposal facility, an incinerator, a recycler authorised for that waste, or a cement kiln authorised to co-process it. Every load moves under a manifest, and the unit files an annual return with the board.

Our page on hazardous waste authorisation explains the application, and the guide on hazardous waste manifests and transport explains the paperwork that follows each load.

Spent solvents: recovery, sale and the risk of informal disposal

Recovering solvent in-house by distillation is both lawful and economical, and most large units do it. What cannot be recovered in-house may be sent to a recycler that holds the right authorisation, or for incineration or co-processing. The legal risk lies in selling spent or mixed solvent informally, to a trader who promises to take it away and asks no questions.

Tankers of spent solvent and process waste dumped into drains, rivers, abandoned borewells or fields at night are a recurring problem in pharmaceutical clusters, and boards and the NGT treat them very seriously because of the risk to groundwater and drinking water. When such dumping is traced back, the generator remains responsible even if a transporter did the dumping, unless it can show the waste left under a valid manifest to an authorised party. For other liquid wastes, see our guide on used oil and chemical sludge disposal.

If a buyer offers to take spent solvent at a price that seems too good, check its authorisation on paper before the first load leaves. A manifest made out to an unauthorised party is not protection; it is evidence.

How to set up solvent and waste compliance in a pharma unit

This is the order we suggest to units preparing for a consent renewal, an expansion or an inspection after a complaint.

If production has grown beyond the consent, see our page on consent for expansion or new products before the next inspection.

Why the solvent mass balance matters so much

A pharma unit buys solvent in large, documented quantities. Some is recovered and reused, some goes out as authorised waste, some is lost to air and some ends up in effluent. If the unit cannot account for a large share of what it bought, the natural question is where it went. Inspectors and joint committees appointed by the NGT have increasingly asked for purchase records, recovery logs and waste manifests side by side for exactly this reason.

When Advocate B.K. Singh defends a pharma unit before a joint committee, the solvent balance is the first document he asks the plant to prepare, because a balance that adds up answers most allegations of illegal dumping before they are made. Where it does not add up, it is far better to find the gap internally, explain it and fix it than to have a committee find it. For residents, the same logic works in reverse: asking the board to examine a unit's solvent balance is a precise, reasonable request that is hard to refuse.

Effluent, evaporators and zero liquid discharge

Bulk drug effluent is often high in organic load and dissolved salts, and solvent traces make it harder to treat. Many units separate high-strength streams and send them to stripping and a multiple-effect evaporator, with only low-strength streams going through biological treatment. In several pharmaceutical clusters, boards have imposed zero liquid discharge conditions, meaning no treated effluent may leave the premises; whether that applies to your unit depends on your consent and your state. Our guide on zero liquid discharge rules explains how these conditions work.

Units in industrial estates often send pre-treated effluent to a common effluent treatment plant, subject to inlet limits. A unit that sends effluent beyond those limits, or bypasses its own treatment, can be held responsible when the common plant fails. See our guide on CETP compliance.

Records every pharma unit should keep ready

Fires, leaks and reactor accidents: who pays

Solvents are flammable and many reactions are hazardous, so fires, runaway reactions and vapour releases are a real risk in pharma plants. Where an accident causes death, injury or damage to property or the environment, section 17 of the NGT Act imposes no-fault liability: the unit must compensate even if it was not negligent. The Supreme Court's decision in M.C. Mehta v Union of India (the Oleum gas case, 1987) laid down absolute liability for hazardous industries, and the Public Liability Insurance Act 1991 requires units handling hazardous substances to carry insurance for immediate relief.

Residents and workers' families affected by such an accident can apply to the NGT for compensation within five years. Our guide on chemical leaks and industrial accident compensation explains how these claims proceed.

If a pharma unit receives a show-cause or closure notice

Notices to pharma units usually follow a complaint, a sampling result or an inspection that found products outside consent, missing manifests or an effluent bypass. Reply within the time allowed, with documents rather than assurances: the solvent balance, returned manifests, the authorisations of transporters and recyclers, monitoring reports and photographs of corrective work. Where the inspection report has misread the plant, say so specifically and offer a joint inspection.

A closure or disconnection direction under section 31A of the Air Act or section 33A of the Water Act can be appealed to the NGT within 30 days of communication, extendable by up to 60 days for sufficient cause. Boards commonly allow a restart once compliance is shown, often against a bank guarantee. Our page on replying to a closure notice explains how we prepare these replies.

Quick compliance check for a pharma unit

Living near a pharma cluster: how to complain

Residents usually notice two things: a chemical or solvent smell, often worst at night, and liquid waste turning up in drains, nullahs or fields. For smell, write to the State Board with dates, times and wind direction, and ask for an inspection of vent controls at the hours it is worst; our guide on industrial odour complaints covers how to document it. For dumped waste, photograph it, note tanker numbers if you can, and complain to the board and the DM the same day so samples are taken before the evidence washes away.

Ask the board, through RTI, for the units' consents, hazardous waste authorisations and inspection reports. If the board does not act, or if wells and handpumps are affected, the NGT can order a joint committee inspection, testing of water sources and restoration at the polluter's cost. For cluster-specific help, see our pages for Baddi, Barotiwala and Nalagarh and Bharuch and Ankleshwar.

Related guides

Pharma units almost always run boilers, covered in our guide on boiler and furnace emission rules. For heavy industry in the same group of guides, see steel and rolling mill pollution.