Hazardous substance

Hazardous substances are encountered by specialist contractors in concrete demolition, special demolition, gutting works, rock breakout and tunnel construction, in natural stone extraction as well as during special operations. They arise as dust, vapor, gas or aerosol during processing operations or are present in components, coatings, sealants and residues. In connection with equipment such as rock and concrete splitters, concrete pulverizers, hydraulic shear (demolition shear), steel shears, multi cutters, stone splitting cylinders, tank cutters and the associated hydraulic power packs, safe handling requires systematic hazardous substance management – objective, forward-looking, and tailored to the respective construction site situation.

Robust risk assessment, method statements and site-specific ventilation and dust control plans embed these measures in daily operations and facilitate verifiable compliance.

Definition: What is meant by a hazardous substance?

A hazardous substance is any substance or mixture that can endanger people and the environment due to its physicochemical or toxicological properties. These include, among others, flammable, corrosive, toxic, sensitizing, carcinogenic, mutagenic and reprotoxic substances as well as environmentally hazardous substances. Process-generated hazardous substances such as fine quartz dust during concrete crushing, fumes when cutting coated metals, or gases from tank residues are also included. In practice, this covers construction materials, coatings, lubricants and operating supplies, exhaust gases, dusts, and residual contents of technical systems. Requirements for classification, labeling and safe handling are generally regulated by standards and must be considered on a project-specific basis. Where relevant, respirable crystalline silica (quartz, RCS), diesel engine emissions, solvent vapors and isocyanates warrant particular attention due to well-documented health risks and stringent occupational exposure limits.

Hazardous substances on construction sites from demolition work to tunnel construction

Depending on the construction task and method, different hazardous substances occur. A prudent approach with adapted equipment selection significantly reduces emissions and exposures – for example, when using concrete pulverizers or rock and concrete splitters, which often generate less fine dust, vibration and noise than percussive methods.

Selecting non-percussive, cold-cutting techniques also reduces secondary hazards such as flying debris, peak noise and hand-arm vibration, supporting both occupational health and neighborhood protection.

Mineral dust in concrete demolition and special demolition

Cutting and breaking concrete produces mineral dust with a respirable quartz fraction. These dusts can irritate the airways and cause long-term lung damage. Methods with controlled material separation – e.g., concrete pulverizers or rock and concrete splitters – limit the “grinding” of the material and thus the formation of fine dust, but still require effective mitigation measures. For concrete and masonry, control strategies should address respirable crystalline silica explicitly.

• Technical dust reduction: water mist, point-of-source extraction, enclosures in sensitive areas.
• Organizational measures: schedule dust-intensive steps in blocks, restrict access, keep material routes short.
• Personal protection: appropriate respiratory protection filters, safety glasses, skin protection for cement-containing dust.
• Supplementary controls: H-class vacuum extraction for tools and housekeeping, wet sweeping instead of dry brushing.

Asbestos, PCBs, PAHs and heavy metals during gutting works and cutting

In existing buildings, hazardous substances are often bound in joint compounds, paints, adhesives, fillers or floor assemblies. Before using concrete pulverizers, hydraulic shear (demolition shear) or multi cutters, qualified investigation and assessment are required. Depending on the result, low-emission methods, negative-pressure containment zones, airlocks and special disposal steps must be provided. Sampling and accredited laboratory analysis precede any disturbance; where suspect materials are present, only licensed procedures with air monitoring and documented clearance are acceptable.

Metalworking: fumes, coatings and residues

When downsizing steel components with steel shears and hydraulic shear (demolition shear), thermal cutting processes can often be avoided, eliminating welding fumes and nitrogen oxides. Nevertheless, coatings (e.g., lead-based paints or chromates) can release dust-like or fibrous hazardous substances. Wetting, covering, and orderly waste disposal logistics prevent spreading. Where feasible, pre-cleaning and targeted coating removal reduce contaminant loads; verify coating chemistry ahead of cutting with suitable test methods and plan containment accordingly.

Tanks, vessels and special operations

With tank cutters and in special operations, flammable vapors, residual hydrocarbons and possible explosive atmospheres are the focus. Typically required are clearance measurement, gas-free status, inerting if necessary, and low-spark work practices. Cleaning and flushing media as well as resulting sludges are considered hazardous substances depending on content and contamination and must be treated accordingly. Hot work permits, continuous monitoring of LEL, oxygen and toxic gases, bonding and grounding, and the use of explosion-protected equipment complement the control concept.

Hazardous substance identification and labeling in practice

A reliable hazardous substance inventory with the relevant working materials and process-generated emissions forms the basis. Safety data sheets, labels in accordance with GHS/CLP, and written work instructions ensure transparency on the construction site and in the workshop.

• Pre-survey: construction age classes, material samples, use history (e.g., industrial plants, tank farms).
• Documentation: keep safety data sheets available, label containers consistently, log decanting.
• Signage: clearly signal areas with hazardous substances and collection points, control access.
• Inventory control: maintain a central register including SDS versioning, substance quantities and storage locations; ensure secondary containers carry complete labels with pictograms.
• Digital access: provide current SDS and work instructions via QR or mobile tools to support point-of-work decisions.

Health effects and exposure pathways

Hazardous substances act via inhalation, skin contact or ingestion. Possible outcomes include acute effects such as irritation and poisoning, as well as chronic effects up to and including carcinogenicity. For exhaust gases (e.g., CO, NOx), mineral fine dust (quartz), solvent-containing vapors, or fibrous dusts, compliance with relevant limit values is essential. Measurements and continuous monitoring – especially in confined areas or in tunnel construction – complement the protective measures. Dermal uptake plays a significant role for oils and solvents; task rotation, skin protection plans and appropriate gloves reduce cumulative dose. Where applicable, health surveillance and biomonitoring support early detection of adverse effects.

Risk reduction according to the STOP principle

The effectiveness and sequence of protective measures follow the proven STOP principle – Substitution, Technical measures, Organizational measures, Personal protective equipment. The aim is to sustainably avoid exposures before personal protective equipment has to take effect.

1. Substitution: choose working methods that release fewer hazardous substances, e.g., concrete pulverizers or rock and concrete splitters instead of dust-intensive percussive methods; use low-emission cleaning and degreasing agents.
2. Technology: water mist systems, point extraction, closed hydraulic circuits, leak detection, adequate ventilation (especially in tunnel construction).
3. Organization: zone work areas, separate material flows, define cleaning routines, document training.
4. PPE: respiratory protection appropriate to the type and concentration of hazardous substance, hand protection against oils/solvents, protective clothing and eye protection.

Verify the effectiveness of controls with direct-reading measurements and observation, then refine the package iteratively until targets are met with a sufficient safety margin.

Example: low-dust concrete separation/cutting

In selective deconstruction, dust exposure can be reduced when concrete pulverizers separate components in a controlled manner and break them down into transportable pieces. Rock and concrete splitters generate crack lines without intensive grinding of the concrete structure (matrix). In addition, water mist at the fracture zone, short drop heights, clean gripping points and coordinated construction logistics up to low-dust removal are effective. Pre-wetting, dedicated one-way haul routes, covered skips and prompt housekeeping with H-class vacuums keep residual dust to a minimum.

Hydraulics, operating supplies and environmental aspects

Hydraulic power packs and attachments are operated with oils that are classified as hazardous substances and, in many cases, as hazardous to water. Seal systems, drip oil management, containment trays and carrying suitable absorbents are therefore part of standard organization. When refilling, the following applies: clean connections, avoid carryover, correctly label and store containers. Where technically suitable, the use of readily biodegradable hydraulic fluids reduces environmental risks in the event of leaks.

• Storage: tip-resistant containers, retention volume, segregation of incompatible substances.
• Readiness: emergency kit for leaks, suitable absorbents, tight collection containers.
• Disposal: separate collection of waste oils, oil-containing operating supplies, filters and wiping cloths.
• Substitution: evaluate biodegradable oils and low-aromatic cleaners for specific applications to minimize environmental impact.

Ventilation, measurement and dust control

In tunnels and interior areas, airflow and fresh air quantity determine exposure. Direct the flow toward the emission source, supply fresh air, and recirculate through filter units – this limits CO, NOx and fine dust. For work involving hazardous substances, event-driven measurements are helpful to assess effectiveness and the need for additional measures. Practical elements include push-pull ventilation near sources, local capture at cutting heads, verified capture velocities, and direct-reading instruments for CO, NO2 and dust; in diesel environments, include a surrogate for diesel particulate exposure where feasible.

Disposal, cleaning and decontamination

Hazardous-substance-containing wastes are kept separate, clearly labeled and handed over according to their properties. Wet cleaning methods, dust-binding wipes and defined cleaning routes prevent spreading. Tools from concrete pulverizers to steel shears must be decontaminated after contact with contaminated materials before they reach other areas. Assign appropriate waste codes, use closed and labeled containers and retain handover records to ensure traceable disposal.

Planning and documentation in the project workflow

A continuous planning thread facilitates safe operation: from investigation to the selection of methods through to instruction, construction logistics and evidence documentation. For work with tank cutters, in natural stone extraction or in special operations, location-specific requirements apply. Documented procedures, clear responsibilities and regular effectiveness checks create transparency. Permit-to-work systems, toolbox briefings and change management for scope adjustments keep controls aligned with evolving site conditions.

Interfaces with products and application areas

The choice of method significantly influences the hazardous substance situation. Concrete pulverizers enable controlled gripping and breaking of concrete components with reduced fine dust generation. Rock and concrete splitters separate components along defined cracks and can limit vibration and emissions – an advantage in sensitive deconstruction or in natural stone extraction. Hydraulic shear (demolition shear), steel shears and multi cutters allow cold separation of metallic structures without thermal fumes. Tank cutters are used on vessels when residual substances and vapors must be considered. Hydraulic power packs supply the equipment efficiently; their operating supplies must be handled carefully as hazardous substances.

• Concrete demolition and special demolition: low-dust methods, water mist, controlled material handling.
• Gutting works and cutting: investigation of hazardous substances, negative-pressure areas, low-emission separation techniques.
• Rock breakout and tunnel construction: airflow control, measurement concepts, minimization of diesel exhaust and dust exposure.
• Natural stone extraction: mechanical splitting methods, dust binding, orderly waste paths.
• Special operations: clearance measurement, low-spark methods, safe handling of contaminated residues.
• Competence and training: documented competence for operators and supervisors in hazardous substance controls, emergency response and disposal pathways.