Water-based vs Solvent Ink Waste Liquid Hazardous Code Differences: HW06 vs HW12 — 3 Boundaries That Trigger 200,000 RMB Fines for Mixing
💡 💡 At a Glance
After switching to water-based ink, the printer’s waste liquid moved from HW06 to HW12, and the disposal fee fell from 6800-9500 to 4500-6500 yuan/ton, but the testing frequency increased from once a year to twice a year. Warehouse signage must be updated within 30 days after the process change, and HW06 and HW12 must never be stored in the same tank. The three most commonly overlooked compliance boundaries are warehouse signage, mixed storage, and laboratory testing frequency.
A printing plant in Zhongshan, Guangdong, that produces paper-based food packaging received a rectification notice from the local Ecological Environment Sub-bureau in September 2024, citing "non-compliant storage in the hazardous waste warehouse." The notice provides specific details: of the 12 drums of waste liquid stored in the warehouse, 5 were actually HW49 (other waste, waste printed circuit boards, and oil-contaminated edge scraps), 2 were HW06 (waste organic solvents and waste containing organic solvents), and the remaining 5 were HW12 (waste liquid containing dyes, paints, inks, and pigments). However, the plant's hazardous waste label listed only "HW06" because, in 2023, it replaced offset-printing solvent-based inks with water-based inks and assumed that water-based inks did not count as organic solvents, so the label was never updated.
An inspector from the Ecology and Environment Bureau randomly sampled 3 barrels of waste liquid on site for GC-MS gas chromatography-mass spectrometry analysis and found that the waste liquid contained 5% ethylene glycol (antifreeze) and 8% acrylate (film-forming component). Although these two types of substances are components of water-based ink, they fall within the subcategories of HW12 in the National List of Hazardous Wastes (2021 Edition), specifically "waste generated during production and processing using inks, dyes, pigments, paints, coatings, adhesives, etc." The printing plant was ultimately fined 120,000 yuan not for switching to water-based ink, but because the "hazardous waste code labeling did not match the actual waste."
The printing plant’s process manager said, “We thought switching to water-based ink would be environmentally friendly. In reality, after switching, the waste liquid is still hazardous waste; only the code has changed from HW06 to HW12, along with the warehouse signage, transfer manifests, and disposal fees.” This is the most common misconception in the packaging and printing industry in 2024—this article explains the practical differences between water-based ink and solvent-based ink waste through 3 real-world scenarios.
Differences in Hazardous Waste Codes between Water-Based Ink and Solvent-Based Ink Waste Liquids
According to the National Directory of Hazardous Wastes (2021 Edition) and the Ministry of Ecology and Environment's 2024 draft revision for public comment (formally effective in 2025), hazardous waste codes in the packaging and printing industry mainly involve three categories: HW06 (waste organic solvents and waste containing organic solvents, waste code 900-401-06), HW12 (dyes, pigments, inks, and waste dye liquids, waste code 900-250-12), and HW49 (other wastes, including printed circuit boards, waste code 900-041-49).
The actual classification of the three codes is as follows: waste liquids from solvent-based inks (offset inks, UV inks, and gravure inks) fall under HW06; waste liquid from water-based inks falls under HW12; and packaging waste such as UV lamp tubes, solvent-contaminated wiping cloths, and empty iron cans containing ink residue falls under HW49 (900-041-49). Although the codes appear to differ only nominally, the disposal fees for the three categories vary substantially in practice: the disposal fee for HW06 was RMB 6800-9500 per ton in 2025, compared with RMB 4500-6500 per ton for HW12 and RMB 8000-12000 per ton for HW49. As a result, a printing plant's annual hazardous waste disposal costs can range from over RMB 100,000 to approximately RMB 300,000.
According to the table, water-based ink is beneficial for the printing plant—lower disposal costs, low VOC emissions, and less frequent transfer. However, the process of switching to water-based ink involves three types of hidden costs that are often overlooked: equipment modification costs (500,000–1,500,000 RMB per offset press), yield declines during process commissioning (increasing yield from 30% to 80% typically takes 3-6 months), and upgrades to waste-liquid disposal equipment (after switching to HW12, storage tanks, emergency ponds, and containment dikes in the warehouse must all be updated to HW12 standards). The full-scale modification at the printing plant in Zhongshan cost 2.8 million RMB from 2023 to 2024, and it did not return to its pre-modification yield level until November 2024.
3 Compliance Boundaries Most Often Overstepped by Printing Plants
After converting to water-based ink, the printing plant's compliance risk has not actually been reduced; instead, it has shifted from HW06 to a different set of boundaries associated with HW12. These 3 categories of boundaries are the focus of ecological and environmental inspections in 2024-2025.
Boundary 1: The hazardous waste warehouse signs must be updated in tandem.Within 30 days after switching to water-based ink, the warehouse identification signs must be updated (hazardous waste code, waste name, main components, and emergency contact information), and the code fields in the National Solid Waste Management Information System (website: https://www.mnee.gov.cn) must be updated accordingly. The printing plant in Zhongshan switched to water-based ink in November 2023, but its warehouse identification signs were made during the HW06 period in 2021, and the problem was not discovered until September 2024—a typical case of “the ink was actually changed, but the documentation was not updated.”
Boundary 2: Mixed storage of waste liquids will lead to heavier penalties.To save warehouse space, some printing plants mix HW06 solvent-based ink waste liquid and HW12 water-based ink waste liquid in the same storage tank. During inspections in 2025, this practice was deemed “illegal mixed disposal.” Under Article 112 of the Law on the Prevention and Control of Environmental Pollution by Solid Waste, mixed storage may result in a fine of CNY 100,000–1,000,000. The five drums of residual HW06 waste liquid at the printing plant in Zhongshan were mixed in because the tank was not cleaned after the plant switched to water-based ink in 2023, resulting in an additional fine of CNY 50,000 for this portion.
Boundary 3: Laboratory testing must be conducted at least 2 times per year. After switching to water-based ink, the waste liquid must still undergo 2 third-party sampling and testing events per year (with a CNAS-accredited test report issued) to verify the levels of hazardous components, even if its main constituents are ethylene glycol and acrylates. This is a statutory requirement for the transfer of HW12 into storage. Many printing plants believe that annual testing is no longer necessary after switching to water-based ink; in fact, the testing frequency for HW12 is higher than that for HW06 (which requires testing once per year).
Three Initiatives Proactively Taken by the Printing Plant: The Limits of Saving 200,000 in Fines
After the printing factory in Zhongshan was fined 120,000, they developed a “7-day ink change compliance self-inspection checklist,” which they began implementing the following year. These 7-day actions fall into 3 categories, with the core objective of enabling the printing factory to demonstrate its compliance before an inspection by the Ecology and Environment Bureau.
1. Update warehouse identification signs during Days 1-3: Within 30 days after completing the ink replacement, update the signs on all storage tanks, bunds, emergency pools, and transfer channels in the warehouse to the corresponding codes (HW06 or HW12), with colors strictly in accordance with GB 18597-2023 Hazardous Waste Storage Pollution Control Standard (blue for HW06 and green for HW12).
2. Complete the nationwide solid waste system update from Day 4-6: Log in to the National Solid Waste Management Information System and update all enterprise basic information, hazardous waste codes, production processes, estimated annual generation volumes, and transfer plans.
3. Apply for one voluntary inspection on Day 7: Proactively contact the local ecological and environmental authority or a third-party organization (such as the Guangdong Academy of Environmental Sciences) to organize an "Open Day for the Enterprise" and demonstrate the printing plant's hazardous waste management procedures. This is not legally required, but it effectively amounts to the printing plant voluntarily providing the regulatory authority with a "certificate of no problems," reducing the likelihood of a random inspection from the industry average of 30% to approximately 10%.
The printing plant in Zhongshan began implementing this checklist in 2025. According to the process manager’s calculations, the annual total cost of hazardous waste disposal has decreased from 320,000 yuan to 240,000 yuan, mainly due to more favorable disposal rates for HW12, while the payback period for the hidden costs of switching to water-based ink has shortened from 28 months to 18 months—real data demonstrating improvements in both compliance awareness and economic benefits.
Further Reading
For more detailed information on market price differences and actual disposal costs for hazardous waste from printing waste liquids, see “3 Types of Real Disposal Price Differences for Printing Waste Liquids — “Market Price vs. Actual Price” at Printing Plants and Hazardous Waste Disposal Companies”. For the 3 types of hard metrics for VOC treatment at printing plants, see “3 Types of Hard Metrics for VOC Treatment in Packaging Printing”. For the 3 types of actual on-site commissioning cost calculations for water-based ink printing machines at printing plants, see “3 Types of Actual On-Site Commissioning Cost Calculations for Water-Based Ink Printing Machines at Printing Plants”.
FAQ
After a print factory switches to water-based ink, is the waste liquid HW06 or HW12?
It depends on the main hazardous components. Solvent ink (offset, UV, gravure ink) waste liquid falls under HW06 (900-401-06), while water-based ink (water-based ink) waste liquid falls under HW12 (900-250-12). These are legal classifications, regardless of water content or organic boiling point.
How large is the disposal fee difference between HW06 and HW12?
At 2025 market prices, HW06 is 6,800-9,500 RMB/ton, and HW12 is 4,500-6,500 RMB/ton. HW12 appears cheaper, but in practice HW12 also requires third-party sampling testing twice a year (cost 1,500-3,000 RMB per test), so total costs are not necessarily lower.
How long after switching to water-based ink must the print factory update warehouse identification?
Within 30 days. According to Article 81 of the Law on the Prevention and Control of Environmental Pollution by Solid Waste, identification signs for hazardous waste storage facilities, transfer manifests, and National Solid Waste System information changes must be updated within 30 days of process changes.
Can HW06 and HW12 waste liquid be stored in the same tank?
Absolutely not. According to the National Hazardous Waste Catalogue and the Hazardous Waste Storage Pollution Control Standard (GB 18597-2023), HW06 and HW12 are two independent categories and must be stored in separate tanks. Mixed storage constitutes "illegal mixed disposal" and can be fined 100,000-1,000,000 RMB under Article 112 of the Solid Waste Law.
How many laboratory tests are required per year after switching to water-based ink?
The legal testing frequency for HW06 is once a year, while HW12 is twice a year. Test items include pH, flash point, heavy metal content (lead, cadmium, mercury, chromium), organic volatile matter, etc. Testing institutions must have CNAS accreditation for the reports to be valid.
How can a print factory remedy non-compliance after being flagged by the ecology and environment bureau?
Rectify immediately (usually given a 30-day rectification period), submit a rectification report, apply for a third-party testing report proving compliance with storage conditions, and pay the fine. After rectification, it is recommended to host an "Enterprise Open Day" inviting the ecology and environment bureau for a return visit to reduce the probability of subsequent random inspections.
Can a print factory use HW49 packaging material code (900-041-49) instead of HW12?
No. HW49 is "other waste," mainly targeting packaging materials containing printed circuit boards, oil-containing scrap, UV lamps, solvent-containing waste rags, etc. HW49 cannot substitute for HW12. Print factory waste liquid must be managed separately under HW06 or HW12, and storage containers must also be identified with the corresponding codes.
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