--- title: "OSHA Silica Limits: Respirable Crystalline Silica | Aethair" description: "OSHA respirable crystalline silica limits: the 50 µg/m³ PEL and 25 µg/m³ action level, who must comply, how exposure is sampled, and a recommended setup." url: https://aethair.io/standards/osha_silica/ --- Compliance · US OSHA 1910.1053 # OSHA Respirable Crystalline Silica Occupational: respirable dust The US Occupational Safety and Health Administration's Respirable Crystalline Silica standard sets the legal limit on how much silica dust workers may be exposed to. It establishes a **permissible exposure limit (PEL) of 50 µg/m³** as an 8-hour time-weighted average and an **action level of 25 µg/m³** that, once reached, triggers mandatory air monitoring and medical surveillance. The standard covers construction, general industry, and maritime work, and requires employers to assess exposures, implement engineering controls such as water suppression and local exhaust, provide respiratory protection where controls are insufficient, and keep records. [Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Configure OSHA silica Monitoring](https://aethair.io/build/?params=silica) At a glance **US OSHA 1910.1053** Occupational: respirable dust 1 parameter · 2 limit values [Respirable Crystalline Silica](https://aethair.io/parameters/silica/) 1 device measures them all - **Thiamis** Trolex Particulate & Dust Monitors [Official text from US OSHA 1910.1053](https://www.osha.gov/silica-crystalline) The standard ## What the OSHA Silica Standard Is It is a hazard-specific occupational rule with serious enforcement behind it, driven by the incurable diseases silica causes. Limit values ## OSHA silica Limit Values Every value US OSHA 1910.1053 publishes for the parameter below, with its averaging period, as the standard states it. [**Respirable Crystalline Silica** Particulate Matter](https://aethair.io/parameters/silica/) **50 µg/m³** *8-hour TWA (PEL)* **25 µg/m³** *8-hour TWA (action level)* Who it applies to ## Who Must Comply Any employer whose work disturbs silica-containing materials falls under the standard: construction contractors cutting, grinding, or drilling concrete and stone; engineered-stone and countertop fabricators; quarrying and mining operations; foundries; and manufacturers working with sand or quartz. The recent wave of accelerated silicosis among engineered-stone countertop workers has sharpened enforcement and public attention. Demonstrable exposure control is now a live legal and reputational issue for these sectors. Monitoring ## How Monitoring Demonstrates Compliance Legal compliance rests on **gravimetric personal sampling**. A size-selective cyclone worn in the worker's breathing zone collects the respirable fraction on a filter, which a laboratory then analyzes for crystalline silica to produce a time-weighted average that can be compared with the PEL and action level. This is the defensible method for enforcement. Alongside it, **real-time respirable-dust monitors** give immediate feedback (which tasks generate the most dust, and whether controls are working), so exposures can be managed as work proceeds rather than discovered after the fact. The two approaches are complementary: real-time monitoring for control, gravimetric sampling for compliance. [Customize this configuration](https://aethair.io/build/?params=silica) ### Who measures each parameter | Parameter | Aethair PRO | Aethair IAQ | External | | - | - | - | - | | [Respirable Crystalline Silica](https://aethair.io/parameters/silica/) | — | — | [1 instrument](https://aethair.io/parameters/silica/) via Thiamis | Devices ## Devices That Cover OSHA silica How much of this standard one Aethair monitor covers, followed by the third-party instruments in the sensor catalog that measure its parameters. Each connects to Environet through a Thiamis gateway, which adds whatever the monitor leaves out. Covers it on its own [**Trolex** Particulate & Dust Monitors](https://aethair.io/sensors/trolex-particulate-dust-monitors/) Solutions ## Solutions Judged Against OSHA silica ### [Perimeter Monitoring](https://aethair.io/solutions/perimeter-monitoring/) Site boundary dust, silica, and noise compliance [All solutions](https://aethair.io/solutions/) Article Library ## Articles on OSHA silica ### [Data Center Air Quality Monitoring, Inside and Out](https://aethair.io/resources/data-center-air-quality-monitoring/) Data center air quality monitoring for operators: ISO 14644 cleanliness in the white space, construction dust, generator emissions, and perimeter noise. ### [How to Choose an Air Quality Monitor: PRO, IAQ, or Thiamis](https://aethair.io/resources/choosing-aethair-monitoring-device/) Compare Aethair PRO, IAQ, and Thiamis to match the right device to your site, from commercial interiors to industrial and fenceline monitoring. ### [OSHA Air Quality Standards 2026: PELs & 29 CFR 1910.1000](https://aethair.io/resources/osha-air-quality-standards-compliance/) OSHA air quality standards for indoor and outdoor work: permissible exposure limits, Table Z-1, 29 CFR 1910.1000, and the heat and wildfire smoke triggers. ### [PM2.5 Exposure Limits & Monitoring: OSHA and NAAQS Standards](https://aethair.io/resources/pm25-monitoring-health-regulatory-guide/) What are the OSHA and NAAQS exposure limits for PM2.5? Fine particulate thresholds explained, plus how continuous monitoring keeps workplaces compliant. [All articles](https://aethair.io/resources/) Questions ## OSHA silica FAQ What is the OSHA exposure limit for silica? The permissible exposure limit is 50 µg/m³ of respirable crystalline silica as an 8-hour time-weighted average, with an action level of 25 µg/m³. Reaching the action level obliges the employer to conduct exposure monitoring and offer medical surveillance to affected workers. Does a real-time dust monitor satisfy the OSHA standard? Not on its own. Compliance with the PEL requires gravimetric sampling with laboratory analysis of the crystalline silica content. A real-time monitor cannot distinguish crystalline silica from other dust. Real-time monitoring is useful for controlling dust and identifying high-exposure tasks, but it supplements the gravimetric compliance method. Who is most at risk from silica exposure? Workers who cut, grind, drill, crush, or blast silica-containing materials: concrete and stone in construction, engineered-stone fabrication, quarrying, mining, foundries, and sandblasting. Engineered-stone countertop fabrication in particular has caused a surge in severe, early-onset silicosis. How do I monitor respirable silica on site? Combine gravimetric personal sampling for compliance with a real-time respirable-dust (PM4) monitor for control and boundary checks. Use the configurator to pair a Thiamis gateway with a respirable-dust monitor and add PM10 and noise for a full construction or quarrying panel.