Identification of Hazardous Waste Risk Level in Central Java Province, Indonesia

Abstract

Hazardous waste may be an environmental and public health threat if not managed properly and may contribute to a regional multi-hazard when other natural disasters also exist. Hazardous and toxic waste may cause industrial disaster if its risks are not well identified and mitigated. This study aims to model the city/district-based risk assessment for each type of hazardous waste in Central Java Province for anticipating hazardous waste disasters and necessary responses. The concept of disaster is used as the method in this study, consisting of hazard, vulnerability, and capacity. The results showed that the generation of hazardous waste in Central Java Province was very large, amounting to 2,886,974.024 tons in 2021. The hazardous waste produced was sourced from 1233 types of businesses/activities in Central Java Province, with 4042 types of hazardous waste. The healthcare sector is identified as the sector that produces the most hazardous waste. Overall, the risk levels of the majority of hazardous waste types fall into the low category.

1. Introduction

Hazardous waste is waste with hazardous properties that can be flammable, corrosive, reactive, or toxic [1]. Hazardous waste can be a risk to human health because of its quantity, concentration, and physical or chemical characteristics that can cause illnesses and significantly contribute to increased mortality. Furthermore, it can also pose a danger to the environment if it is not properly managed [2]. To seek the appropriate management for hazardous waste in each setting, risk assessment is needed to determine the risk priority, which can help the decision makers to identify any possible actions that can be taken to manage the risks [3].

One of the main sources of hazardous waste is industries that involve heavy metals in their activities, such as electronic, painting, metal formation, and automobile industries. Industries that produce volatile chemicals, flammables components, organic solvents, nuclear reactors, and petroleum also become a source of hazardous waste [4]. The types of hazardous waste produced by each business sector are also very diverse. In China, there are 3000 hazardous chemicals that are currently being produced and used, with 148 of them identified as highly toxic materials [5]. In Spain, the largest amount of hazardous waste was identified in the manufacture sector, specifically in the base-metal industry, which generated 2.63 million tons of hazardous waste, followed by the chemical, pharmaceutical, rubber, and plastic industries as the second largest producers of hazardous waste with 1.45 million tons. Meanwhile, industries that produce computers, electronics, optical products, electrical equipment, and motor vehicles ranked 3rd among the industries that produced the highest amount of hazardous waste, generating 656,000 tons of hazardous waste in 2016 [6].

The existence of industry in a region does indeed help to improve the local economy, but it can also lead to disasters, known as industrial disasters, triggered by technological failures. Densely populated urban areas with unplanned allocation of infrastructure, especially the industrial and warehousing facilities, can be under risk of fires, explosions, or toxic substance release in the areas near the community [7]. Those events will not only kill or injure many people inside and outside the factory, but the spread of these hazardous substances will also damage the environment around the factory.

Hazardous waste is one of the causes of global ecological hazards, as well as the cause of environmental disasters [5]. Several investigations had been taken in the past which indicate improper waste management, specifically poor and illegal practices of hazardous waste disposal, which had caused contamination of soil and groundwater [8]. Contaminated sites were found in regions in many low- and middle-income countries, such as Ramis River in Peru, which was polluted by arsenic from mine tailings, affecting 15,000 local residents who used the river as their source of drinking water; the soil in Eastern Ghana which was polluted by mercury due to gold mining activities, which put more than 5000 people at risk; the soil and air in an industrial town in Kazakhstan which was polluted by lead, putting 40,000 people who were inhaling the highly contaminated vapors at risk; and hexavalent chromium which was found polluting the rivers, waterways, soil, and fields in India, risking the life of 60,000 local residents [9]. There are also notable catastrophic events in Japan even though the country is highly developed, such as Minamata disease which killed more than 1000 people because of methylmercury ingested by the fish in the water, and Itai-itai disease, which killed 380 people residing in rice farming areas irrigated by a river contaminated by cadmium. Many contaminated sites were a result of both earlier and present industrial activities that caused an accumulation of countless hazardous chemical contaminants in the environment [10]. Therefore, hazardous waste should be managed properly to prevent it from polluting the environment and posing threats to human health.

Disaster events can be calculated by measuring the potential losses that may be caused by paying attention to hazards which have the potential to cause damage or loss of human life. Attention also needs to be given to vulnerability, which is a compilation of conditions and circumstances of consequences (physical, social, economic, and environmental factors) that can adversely affect disaster relief efforts. In determining the danger of hazardous waste, there are various conditions that are characteristic of hazardous waste [11] including dangerous nature; toxic to human health; exposure routes of hazardous waste that can pose a danger to humans [12]; physical form, composition, and reactivity (fire and explosion) [13]; location, types and existing laws and regulations [12]; the amount of hazardous waste generation [12,13], and the quantification of which has the potential to create an emergency in the event of accidental spillage and release of hazardous waste from various locations.

It is also necessary to consider the capacity of the community. Capacity is the strength and potential ability to prevent, survive, reduce, and be prepared for an emergency and disaster [14,15,16]. Public policy and the national disaster management used to put their focus on recovery or relief efforts after the disaster happened. However, resources are limited, especially when the scale of disaster increases [17]. Several efforts should be taken to improve the capacity of the community, such as issuing disaster risk reduction policies; establishing effective coordination and operational cooperation between all related organizations and institutions with the protection and rescue forces; providing infrastructure and equipment with the aims to protect and rescue; holding training for disaster preparedness; and performing risk assessment to develop protection and rescue plans [18].

Assessing the risk of hazardous waste in thousands of contaminated sites used to be a difficult process in United States before the Hazard Ranking System (HRS) was published by the Environmental Protection Agency (EPA) in 1990 [9]. Meanwhile, the Government of the Republic of Indonesia has also released a regulation in 2018 in the form of Regulation of the Minister of Environment and Forestry Number P.101/Menlhk/Setjen/Kum.1/11/2018 on Guidelines for Recovery of Hazardous and Toxic Waste-Contaminated Land. The regulation consists of hazardous waste categories, contaminant impacts on those affected, hazardous waste management, the existence of institutional for hazardous waste emergency response in provincial scale, and emergency programs. However, there are few differences between both regulations. For example, in EPA, the pathways are also included and evaluation is still needed to assess the likelihood of future or continuing release, and migration potential of the hazardous materials [9], while this is not the case in the Ministerial Regulation.

In Indonesia, the generation of hazardous waste has also increased from 200,000 tons/year in 1990 to 1,000,000 tons/year in 2010 [9]. The province with the third-largest population in Indonesia is Central Java Province. This province has 35 districts/cities with a total population of 36,742,501 people. The number of working factories in Central Java continues to rise as both foreign and local investments pour in.

Currently, existing studies on hazardous waste risk assessment in Indonesia are still limited, whereas risk assessment is very important to protect the public health and the environment. Without a proper, accurate, and detailed risk assessment, the impact of hazardous waste on the community will be unpredictable and proper mitigation actions cannot be taken, leading to possible huge impacts to the community. Hence, performing risk assessment is important to overcome hazardous waste disasters in Central Java. This study aims to model the city/district-based risk assessment for each type of hazardous waste in Central Java Province for anticipating hazardous waste disasters and necessary responses, with the development of identification parameters or elements of hazardous and toxic substances and hazardous and toxic waste risk assessment as the primary novelty aspect of this study. Furthermore, remodeling the risk and causes of risk in industrial disasters by categorization of the disaster, hazardous and toxic substances, and hazardous and toxic waste aspects is also conducted.

2. Materials and Methods

2.1. Research Location

This research was performed in Central Java Province, Indonesia.

2.2. Data Collection

Data collection methods applied in this study were in-depth interviews and focus group discussions with local industries and environmental and forestry key personnel in Central Java’s Districts using a well-developed checklist approved by the Ministry of Environmental and Forestry (MEF). After data collection was completed, risk assessment was conducted using a semi-quantitative analysis, with probability, vulnerability, and hazard criteria based on the Ministry of Environment and Forestry (MEF)-approved method. The potential hazards and the level of exposure were scrutinized in the risk assessment. Referring to the Regulation of the MEF Number 74 of 2019 on Hazardous Material and Hazardous Wastes Management Emergency Program, data and information required for risk assessment are:

• type of industries,
• activity of industries,
• hazardous waste category,
• hazardous waste classification,
• hazardous waste generation,
• source of hazardous waste,
• potential threats to public health,
• hazardous waste management capacity,
• the existence of institutions for hazardous waste emergency response,
• provincial hazardous waste emergency program.

Based on the provisions of the Ministry of Environment’s regulations, business units/activities in Indonesia are divided into 6 sectors: manufacture, agroindustry, energy and oil and gas mining, infrastructure, services, and health care (

Table 1. Industry Sector Classification According to the Regulation of the Ministry of Environment and Forestry in Indonesia.

No	Sector	Sector Details
1	Manufacture	Chemical industries, manufacture
2	Agroindustry	Agroindustry
3	Energy and Oil and Gas Mining	Energy, mining and oil and gas
4	Infrastructure	Infrastructure & construction
5	Services	Hazardous waste treatment and transports
6	Health Care	Hospitals, Community Health services, Health Clinics, Laboratories

). The source of data was the recording and reporting system of the Ministry of Environment and Forestry of the Republic of Indonesia.

2.3. Risk Analysis and Risk Rating

Data that were relevant to hazardous waste were categorized based on the hazardous waste category, hazardous waste classification, hazardous waste generation, source of hazardous waste, potential threats to public health, hazardous waste management capacity, institutional hazardous waste emergency responses, and provincial hazardous waste emergency program. According to Peraturan Pemerintah Republik Indonesia No. 22/2021, category 1 is for hazardous materials that have an acute (fast or sudden) and direct impact on humans, as well as a negative impact on the environment. Meanwhile category 2 is for a hazardous material that has a non-acute effect (delay) and has an indirect impact on humans and the environment. This category has toxicity that tends to be sub-chronic or chronic (long-term). The collected data were assessed to determine the risk rating using the risk potential hazard value criteria as listed in

Table 2. Hazardous Waste Potential Hazard Value Criteria.

No	Components	Code	Hazards Potential	Hazards Potential Level
				Value = 1	Value = 2	Value = 3
1	Hazard	A	Hazardous waste generation	<10 tons	10–30 tons	>30 tons
		B	Hazardous waste category	hazardous waste category 2	Hazardous waste category 1
2	Vulnerability	C	Number of affected population	<16 million people	16–32 million people	>32 million people
3	Capacity	D	Hazardous waste Management Capacity	there are >2 areas contaminated by hazardous waste and emergency events	there are 1–2 areas contaminated by hazardous waste and emergency events	There is no land contaminated by hazardous waste and emergency events
		E	The existence of institutional for hazardous waste emergency response	Not available	Available
		F	The existence of a potential hazardous waste emergency program on a provincial scale	Not available	Available

.

After the risk had been rated, data were calculated using the following formula:

$$\mathrm{R}=\left(\sum A+\sum B\right)\times \left(\frac{\sum C}{\left(\sum D+\sum E+\sum F\right)}\right)$$

(1)

$$\mathrm{RISK}=Hazards\times \left(Vulnerability/Capacity\right)$$

(2)

2.4. Risk Matrix

All results of the categorization of hazardous waste, hazardous waste generation, number of impacted populations, hazardous waste management capacity, institutional hazardous waste emergency response, and provincial hazardous waste emergency program were given a score using a Likert scale of 1 to 3 to determine the probability of risk. The scores of 1.5–3, 0.8–1.5, and 0–0.7 are categorized as high, medium, and low risks, respectively (Figure 1).

2.5. Data Analysis

The scores acquired from the risk level were summed up and divided by the number of samples to obtain the average score of the industrial disaster potential.

2.6. Risk Mapping

This mapping used the Geographic Information System (GIS) to portray districts in Central Java based on the risk level of hazardous waste. Based on this mapping, the trend, distribution, and identification of which district that has the highest risk were analyzed.

2.7. Ethical Approval

This study was approved by of the Research and Community Engagement Ethical Committee of Public Health, Universitas Indonesia, with the approval number Ket-35/UN2.F10.D11/PPM.00.02/2023.

3. Results

3.1. General Description of Central Java and Hazardous Waste Generation

Central Java, as reflected by its name, is a 32,801 km² area located in the central part of Java Island with a large population totaling 37.49 million [10]. There are 1233 units of businesses/activities/industries in Central Java, generating 4042 types of hazardous waste. In 2021, the total amount of hazardous waste generated in Central Java was 2,886,974.024 tons. The healthcare sector was the sector that generated the largest amount of hazardous waste in this province, which is in line with the number of residents in Central Java Province as the province with the 3rd largest population in Indonesia, which makes it necessary to have a large number of health care facilities. The breakdown of the amount, average, minimum–maximum, and standard deviation of hazardous waste generation by sector of various business units/activities is presented in

Table 3. Hazardous Waste Generation Data (Tons/Year) By Sector in Central Java Province in 2021.

Hazardous and Toxic Waste Producing Sector with 4042 Types of Hazardous Waste	Quantity (Tons)	Average (Tons)	Minimum—Maximum (Tons)	Standard Deviation
Manufacture	536,869.545	260.49	0.00005–231,202	5575.143
Agroindustry	498.171	11.071	0.0009–300	50.119
Energy and Oil and Gas Mining	461,341.423	2059.56	0.0001–346,244.91	23,602.727
Infrastructure	2.235	0.106	0.0001–0.963	0.23
Service	18,421.396	84.502	0.00023–6104	611.851
Health Care	1,869,841.254	1082.084	0.00001–1,541,386	37,210.985
Total	2,886,974.024	671.858	0.00001–1,541,386	24,510.193

.

The city/district that produced the most hazardous waste generation was Kebumen District, while the district that produced the least hazardous waste was Karanganyar District. On average, each city/district in Central Java Province produces hazardous waste of 671.858 tons/year, with a very wide minimum and maximum value range of 0.00001–1,541,386 tons/year. The following (

Table 4. Amount of Hazardous Waste Generation (Tons/Year) by District/City in Central Java Province in 2021.

District/City	Quantity (Tons)	Average (Tons)	Minimum—Maximum (Tons)	Standard Deviation
Cilacap District	20,368.228	145.487	0.00005–10,530.81	972.769
Banyumas District	3354.565	90.664	0.003–3065.08	502.942
Purbalingga District	9724.068	78.420	0.0001–6050	608.776
Banjarnegara District	218.232	3.968	0.001–56.4	12.291
Kebumen District	1,606,396.285	8,280,393	0.00001–1,541,386	110,733.740
Purworejo District	64,876.040	1029.778	0.0005–36,427	5597.232
Magelang District	14,231.369	130.563	0.0003–6104	700.775
Temanggung District	147,420.323	2541.730	0.003–97,148	13,927.699
Wonosobo District	84,069.323	2272.144	0.0004–83,906	13,793.328
Klaten District	2013.057	38.713	0.0012–1226.79	193.718
Sukoharjo District	80,460.020	506.038	0.001–47,554	3823.763
Wonogiri District	9642.39	56.06	0.0005–5400	470.97
Karanganyar District	140.559	1.579	0.0005–88.579	10.057
Sragen District	9169.667	130.995	0.0001–4363.6	708.268
Boyolali District	246,745.388	2372.552	0.0003–231,202	22,692.538
Grobogan District	735.724	5.145	0.005–350	30.797
Blora District	3131.659	59.088	0.002–998	214.61
Rembang District	2206.155	21.011	0.001–1825	179.048
Pati District	3151.539	17.128	0.001–480	66.889
Kudus District	2857.421	14.287	0.00035–1293.25	99.543
Jepara District	442,972.722	2488.611	0.0009–346,244.91	26,462.267
Demak District	9937.673	45.378	0.00014–1467,7	183.490
Semarang District	2065.438	6.129	0.0001–267,31	25.895
Kendal District	141.979	2.898	0.00049–23.4	5.068
Batang District	26,056.415	123.490	0.001–8213.007	836.781
Pekalongan District	999.259	17.844	0.0008–472	68.865
Pemalang District	190,516	2.323	0.0005–64.75	8.697
Tegal District	76,813.539	1449.312	0.00039–10,950	3741.666
Brebes District	298.205	6.777	0.0004–103.053	18.311
Semarang City	9025.958	15.535	0.001–5160	218.837
Salatiga City	5585.942	67.301	0.00002–2400	348.215
Magelang City	292.586	12.721	0.024–118.897	29.373
Surakarta City	1082.965	6.118	0.00023–175.5	22.181
Tegal City	236.590	9.858	0.02–69.98	21.335
Pekalongan City	362.476	12.083	0.05–119.95	26.097
Total	2,886,974.024	671.858	0.00001–1541.386	24,510.193

) is the amount of hazardous waste generation, average, maximum and minimum, as well as the standard deviation from hazardous waste generation based on city/district in Central Java Province:

When the generation of hazardous waste was identified per sector by city/district, the generation of hazardous waste in the manufacture sector was mostly occurred in in Boyolali District. The generation of hazardous waste in the agro-industrial sector mostly occurred in Kudus District. In the energy and oil and gas mining sectors, most hazardous waste was generated in Jepara District. The city of Semarang produced the most hazardous waste in the infrastructure sector while Magelang District produced the most hazardous waste in the service sector. In the health care sector, Kebumen District produced the most hazardous waste. Details of hazardous waste generation by district/city and sector are found in

Table 5. Hazardous Waste Data (Tons/Year) of Various Sectors by City/District in Central Java Province in 2021.

District/City	Manufacture		Agroindustry		Energy and Oil and Gas Mining		Infrastructure		Service		Health Care
	Sum	Average	Sum	Average	Sum	Average	Sum	Average	Sum	Average	Sum	Average
Cilacap District	11,721.756	418.634	-	-	5311.402	87.072	-	-	1.059	1.059	3334.011	3334.011
Banyumas District	102,990	51.495	0.910	0.910	14.686	7.343	-	-	3067.776	766.944	168.202	6.007
Purbalingga District	9550.402	108.527	-	-	-	-	-	-	-	-	173.666	4.824
Banjarnegara District	89.740	11.218	-	-	19.932	1.107	-	-	-	-	108.560	3.743
Kebumen District	1.293	0.129	-	-	4.201	0.200	-	-	-	-	1,606,390.790	9855.158
Purworejo District	385.194	48.149	-	-	-	-	-	-	-	-	64,490.846	1151.623
Magelang District	4248.820	124.965	-	-	-	-	-	-	9517.347	679.811	463.146	7.985
Temanggung District	102,951.668	2287.815	-	-	-	-	-	-	0.060	0.020	44,468.596	4446.860
Wonosobo District	9.379	0.426	-	-	1.334	0.167	-	-	0.300	0.300	84,058.310	14,009.718
Klaten District	1929.227	128.615	-	-	-	-	-	-	-	-	83.831	2.266
Sukoharjo District	26,736.277	300.408	-	-	-	-	-	-	5815.734	242.322	47,907.756	998.078
Wonogiri District	9304.808	273.671	-	-	0.601	0.2003	-	-	-	-	336.981	2.496
Karanganyar District	136.062	3.092	-	-	-	-	-	-	-	-	4.497	0.100
Sragen District	9088.970	193.382	-	-	-	-	-	-	-	-	80.697	3.509
Boyolali District	233,560.079	3073.159	-	-	-	-	-	-	-	-	13,184.509	488.315
Grobogan District	608.749	9.086	-	-	1.187	0.119	-	-	1.978	0.090	123.810	2.814
Blora District	923.328	131.904	-	-	1966.319	178.756	-	-	-	-	242.012	6.915
Rembang District	1927.835	36.374	-	-	6	0.750	-	-	-	-	272.060	5.518
Pati District	2752.58	29.919	166.532	15.139	-	-	-	-	-	-	232.427	2.869
Kudus District	2224.347	24.993	320.810	40.101	-	-	-	-	1.864	0.266	310.4	3.233
Jepara District	5581.566	94.603	3.748	0.750	437,199.115	12,858.797	-	-	-	-	188.294	2.354
Demak District	9785.403	67.954	0.191	0.038	5.049	5.049	-	-	-	-	147.031	2.131
Semarang District	1843.309	6.537	5.940	0.495	-	-	0.1047	0.0175	0.148	0.037	215.936	6.544
Kendal District	55.322	1.419	-	-	-	-	-	-	-	-	86.657	8.666
Batang District	9148.906	54.136	-	-	16,799.9	800.0	-	-	0.01	0.0017	107.565	7.171
Pekalongan District	896.430	23.590	-	-	1.3298	0.222	-	-	-	-	101.5	8.458
Pemalang District	4.355	0.544	-	-	-	-	-	-	0.231	0.046	185.930	2.695
Tegal District	76,807.081	2477.648	-	-	-	-	-	-	-	-	6.458	0.294
Brebes District	121.399	9.338	-	-	-	-	-	-	-	-	176.806	5.703
Semarang City	8555.002	25.614	0.041	0.0137	10.26	0.733	1.942	0.149	11.867	0.140	446.846	3.385
Salatiga City	5468.312	130.198	-	-	0.073	0.0121	-	-	-	-	117.557	3.359
Magelang City	-	-	-	-	-	-	-	-	-	-	292.586	12.721
Surakarta City	30.983	0.968	-	-	-	-	0.148	0.148	2.293	0.064	1049.541	9.718
Tegal City	120.17	17.167	-	-	-	-	0.04	0.04	0.73	0.73	115.65	7.71
Pekalongan City	197	49.25	-	-	-	-	-	-	-	-	165.476	6.364

.

3.2. Types and Characteristics of Hazardous Waste in Central Java Province

From all hazardous waste produced in Central Java Province from all sectors, most had the characteristics of toxicity. However, there was also hazardous waste with flammable, corrosive, reactivity, and infectious characteristics. The following (

Table 6. Identification of Type and Characteristics of Hazardous Waste by Sector in Central Java Province in 2021.

Sector	Hazard Classification of Hazardous Material/Waste (HMW)	Characteristics
Manufacture	Residual and expired adhesive or glue (used glue)	Dangerous, irritant
	Leachate	Toxicity
	Used battery/expired battery	Corrosive, toxicity
	Antitick	No hazardous materials
	Expired chemicals	Toxicity
	Used bearings	Toxicity
	Bottom ash	Dangerous, carcinogens, irritants
	Bulb TL	Toxicity
	Liquid H2O2	Oxidizing, corrosive, irritants
	Leftover/damaged paint	Dangerous, carcinogens, toxicity
	Used cartridges	Dangerous
	Chemicals	Dangerous, carcinogens, toxicity, irritants
	Dust from the air pollution control unit	Irritant
	Used filters from air pollution control facilities	Flammable, reactive, toxic, infectious
	Filter paper ex. analysis	Toxicity
	Fly ash	Dangerous, carcinogens, irritants
	Used grease	Toxicity
	Used majun fabrics	Flammable solids
	Rubber	Toxicity
	Rubber rolls	Toxicity
	Used hazardous packaging	Toxicity
	Contaminated packaging	Toxicity
	Glue crust	Toxicity
	Paper + rubber	Toxicity
	Rolling paper	Toxicity
	Filter paper	Toxicity
	Hazardous waste wool	Toxicity
	Used brushes	Toxicity
	Used Lamps	Toxicity
	Used TL lamps	Toxicity
	Used glue	Toxicity
	Clinical infectious	Infectious
	Alkaline waste	Toxicity
	Liquid waste	Toxicity, dangerous
	Liquid waste leftover from drug process	Toxicity
	Waste from laboratories containing hazardous substances	Flammable, toxicity, dangerous, carcinogen, irritant
	Laboratory waste	Flammable, toxicity, dangerous, carcinogen, irritant
	Waste paint residue	Dangerous, carcinogens, toxicity
	Waste residual glue	Toxicity
	Used lubricating oil	Flammable, toxicity, dangerous
	NaHS	Dangerous, Corrosive, Irritants
	Hazard-contaminated laboratory equipment	Toxicity, dangerous
	Used plastic/plastic glue	Toxicity
	Hair	Toxicity
	Real hair	Toxicity
	Residues from the washing process	Toxicity, dangerous
	Fumigation residues	Toxicity, irritants
	Production process residues and formulations	Toxicity, irritants
	Used resins	Irritant
	Screen printing	Dangerous, carcinogens, toxicity
	Residual hazardous chemicals	Flammable, toxicity, dangerous, carcinogen, irritant
	Residual glue	Toxicity
	Residual use of chemicals	Flammable, toxicity, dangerous, carcinogen, irritant
	Rest of the blasting process	Toxicity, dangerous
	Sludge	Flammable, irritant
	Sludge WWTP	Flammable, irritant
	Sludge oil &/animal fat &/vegetable	Dangerous, toxicity
	Sludge painting	Dangerous, carcinogens, toxicity
	Sludge ink	Dangerous, toxicity
	Dirty thinner	Flammable, corrosive, dangerous, carcinogen
	Used thinner	Flammable, corrosive, dangerous, carcinogen
	Used ink	Irritant
	Used toner	Irritants, toxicity
	Used glue	Toxicity
Agroindustry	Waste from laboratories containing hazardous substances	Flammable, toxicity, dangerous, carcinogen, irritant
	Laboratory waste	Flammable, toxicity, dangerous, carcinogen, irritant
Energy and Oil and Gas Mining	Used absorbents	Reactive, flammable, irritant
	Ash blasting	Irritant, toxicity, dangerous
	Materials or products that do not meet technical specifications, expired and residual	Toxicity
	Paint	Dangerous, carcinogens, toxicity
	Used filters	Flammable, reactive, toxic, infectious
	Used filters from air pollution control facilities	Toxic, infectious
	Used filters including clay spent filters	Infectious
	Air filter	Flammable, reactive, toxic, infectious
	Fly ash incinerator	Dangerous, carcinogens, irritants
	LED lights	Toxicity
	Contaminated liquid waste	Flammable, toxicity, dangerous, carcinogen, irritant
	Waste from laboratories containing hazardous substances	Flammable, toxicity, dangerous, carcinogen, irritant
	E-waste includes Cathode Ray Tube (CRT), TL lamps, Printed Circuit Board (PCB), and wire rubber	Toxicity
	Clinical waste with infectious characteristics	Infectious
Service	Hazard contaminated oil	Flammable, toxicity, dangerous
	Used plastic wrap	Toxicity, dangerous
	Bottom residues of petroleum tanks	Flammable, toxicity, dangerous
	Residues of production processes or reactions (sulfur, pyrite)	Flammable, toxicity, dangerous
	Used sieve	Toxic, infectious
	Used gloves	Toxicity
	Slag or bottom ash incinerator	Dangerous, carcinogens, irritants
	Sludge from the cleaning and degreasing process	Flammable, irritant
	Sludge of production processes and storage facilities of petroleum or natural gas	Toxicity
	Spent sodium hydroxide/caustic soda	Dangerous, corrosive, irritants
Infrastructure	Hazard contaminated oil	Flammable, toxicity, dangerous
	Used toner	Irritants, toxicity
	Used Ink	Irritant
Health Care	Infectious clinical waste	Infectious
	Incinerator ash	Dangerous, carcinogens, irritants
	Expired chemicals, chemical and pharmaceutical product packaging, hazardous mixing waste, non-hazardous mixing waste, infectious clinical waste	Toxicity, flammable
	Expired chemicals (Laboratories)	Toxicity
	Fly ash incinerator and slag or bottom ash from incinerator	Dangerous, carcinogens, irritants
	Used packaging of pharmaceutical products	Toxicity
	Waste used for building maintenance	Toxicity
	Sharp object waste	Infectious
	Laboratory liquid waste	Flammable, toxicity, dangerous, carcinogen, irritant
	Waste paints and varnishes containing organic solvents	Flammable, reactive, corrosive
	Waste from laboratories containing hazardous substances	Flammable, toxicity, dangerous, carcinogen, irritant
	Infectious waste; pharmaceutical hazardous waste	Flammable, toxicity, dangerous, carcinogen, irritant, infectious
	Chemical and pharmaceutical waste	Flammable, toxicity, dangerous, carcinogen, irritant
	Infectious clinical waste	Flammable, toxicity, dangerous, carcinogen, irritant
	Lab waste	Flammable, toxicity, dangerous, carcinogen, irritant
	Laboratory waste containing hazardous substances	Flammable, toxicity, dangerous, carcinogen, irritant
	Medical waste	Infectious
	Cytotoxic waste	Toxicity
	Hazard contaminated waste	Flammable, toxicity, dangerous, carcinogen, irritant
	Broken glass, shards	Dangerous
	Medical equipment containing heavy metals, including mercury (Hg), Cadmium (Cd), and the like	Toxicity, dangerous
	Expired pharmaceutical products	Toxicity

) was the results of the type and characteristics of hazardous waste identification in Central Java Province:

3.3. Descriptive of Hazardous Waste Potential Criteria

Majority of the hazardous waste category produced in Central Java Province were identified as value 1 (hazardous waste category 2). Hazardous waste generation were mostly less than 10 tons. All cities & districts already have management of hazardous waste. The following (

Table 7. Description of Hazardous Waste Score in Central Java Province in 2021.

No	City/District	Hazardous Waste Value Score	Tonnage Score	Total Hazard	Hazardous Waste Management Capacity	The Existence of Provincial Hazardous Emergency Program	Total Capacity
1	Cilacap District	1 = 61.7% 2 = 38.3%	1 = 80.1% 2 = 8.5% 3 = 11.3%	2 = 50.4% 3 = 34% 4 = 11.3% 5 = 4.3%	3 = 100%	2 = 100%	6 = 15.6% 7 = 84.4%
2	Banyumas District	1 = 2.6% 2 = 76.3% 3 = 7.9%	NO DATA	2 = 5.4% 3 = 75.7% 4 = 10.8% 5 = 8.1%	3 = 100%	1 = 100%	6 = 100%
3	Purbalingga District	1 = 60.5% 2 = 39.5%	1 = 90.3% 2 = 5.6% 3 = 4.0%	2 = 56.5% 3 = 35.5% 4 = 6.5% 5 = 1.6%	3 = 100%	1 = 100%	5 = 29% 6 = 71%
4	Banjarnegara District	1 = 65.5% 2 = 34.5%	1 = 90.9% 2 = 3.6% 3 = 5.5%	2 = 63.6% 3 = 29.2% 4 = 1.8% 5 = 5.5%	3 = 100%	1 = 100%	5 = 100%
5	Kebumen District	1 = 35.1% 2 = 64.9%	1 = 92.8% 2 = 2.6% 3 = 4.6%	2 = 34.5% 3 = 58.8% 4 = 2.1% 5 = 4.6%	3 = 100%	1 = 100%	5 = 94.8% 6 = 5.2%
6	Purworejo District	1 = 30.2% 2 = 69.8%	1 = 82.5% 2 = 3.2% 3 = 14.3%	2 = 23.8% 3 = 60.3% 4 = 6.3% 5 = 9.5%	3 = 100%	1 = 100%	1 = 1.6% 5 = 93.8% 6 = 4.7%
7	Magelang District	1 = 39.6% 2 = 60.4%	1 = 84.7% 2 = 3.6% 3 = 11.7%	2 = 28.8% 3 = 58.6% 4 = 9% 5 = 3.6%	3 = 100%	1 = 100%	5 = 64.9% 6 = 35.1%
8	Temanggung District	1 = 79.3% 2 = 20.7%	1 = 89.7% 2 = 1.7% 3 = 8.6%	2 = 74.1% 3 = 15.5% 4 = 6.9% 5 = 3.4%	3 = 100%	1 = 100%	5 = 44.8% 6 = 55.2%
9	Wonosobo District	1=0.3% 2 = 29.7%	1 = 91.9% 3 = 8.1%	2 = 70.3% 3 = 21.6% 5 = 8.1%	3 = 100%	1 = 100%	5 = 2.7% 6 = 97.3%
10	Klaten District	1 = 60.4% 2 = 39.6%	1 = 88.7% 2 = 5.7% 3 = 5.7%	2 = 54.7% 3 = 34% 4 = 11.3%	3 = 100%	1 = 100%	5 = 100%
11	Sukoharjo District	1 = 43.4% 2 = 36.6%	1 = 75.6% 2 = 3.8% 3 = 20.6%	2 = 46.9% 3 = 32.7% 4 = 14.8% 5 = 5.6%	3 = 100%	1 = 100%	5 = 36.4% 6 = 63.6%
12	Wonogiri District	1 = 47.1% 2 = 52.9%	1 = 91.9% 2 = 2.9% 3 = 5.2%	2 = 42.4% 3 = 50% 4 = 6.4% 5 = 1.2%	3 = 100%	1 = 100%	5 = 39.5% 6 = 60.5%
13	Karanganyar District	1 = 66.3% 2 = 33.7%	1 = 97.8% 3 = 2.2%	2 = 64% 3 = 33.7% 4 = 2.2%	3 = 100%	1 = 100%	5 = 41.6% 6 = 58.4%
14	Sragen District	1 = 64.3% 2 = 35.7%	1 = 91.4% 2 = 4.3% 3 = 4.3%	2 = 60% 3 = 31.4% 4 = 8.6%	3 = 100%	1 = 100%	5 = 85.7% 6 = 14.3%
15	Boyolali District	1 = 70.2% 2 = 29.7%	1 = 84.6% 2 = 4.8% 3 = 10.6%	2 = 57.7% 3 = 30.8% 4 = 9.6% 5 = 1.9%	3 = 100%	1 = 100%	5 = 46.2% 6 = 53.8%
16	Grobogan District	1 = 61.5% 2 = 38.5%	1 = 88.8% 2 = 2.8% 3 = 8.4%	2 = 55.2% 3 = 35% 4 = 6.3% 5 = 3.5%	3 = 100%	1 = 100%	5 = 30.1% 6 = 69.9%
17	Blora District	1 = 24.5% 2 = 75.5%	1 = 81.1% 2 = 5.7% 3 = 13.2%	2 = 22.6% 3 = 58.5% 4 = 7.5% 5 = 11.3%	3 = 100%	2 = 100%	6 = 100%
18	Rembang District	1 = 55.2% 2 = 44.8%	1 = 35.2% 2 = 1.9% 3 = 62.9%	2 = 7.6% 3 = 29.5% 4 = 45.7% 5 = 17.1%	3 = 100%	1 = 100%	5 = 49.5% 6 = 50.5%
19	Pati District	1 = 55.4% 2 = 44.6%	1 = 90.8% 2 = 0.5% 3 = 8.7%	2 = 49.5% 3 = 41.3% 4 = 6.5% 5 = 2.7%	2 = 2.7% 3 = 97.3%	1 = 100%	4 = 2.7% 5 = 38.6% 6 = 58.7%
20	Kudus District	1 = 53.5% 2 = 46.5%	1 = 87% 2 = 3.5% 3 = 9.5%	2 = 48.5% 3 = 40% 4 = 5.5% 5 = 6%	3 = 100%	1 = 100%	5 = 63% 6 = 37%
21	Jepara District	1 = 51.9% 2 = 48.1%	1 = 84% 2 = 5.5% 3 = 10.5%	2 = 41.4% 3 = 44.8% 4 = 11.6% 5 = 2.2%	3 = 100%	1 = 100%	5 = 82.3% 6 = 17.7%
22	Demak District	2 = 57% 3 = 41%	1 = 77.2% 2 = 3.4% 3 = 11.8%	2 = 48.4% 3 = 37.4% 4 = 12.3% 5 = 1.8%	3 = 100%	1 = 100%	5 = 53.9% 6 = 46.1%
23	Semarang District	1 = 74.4% 2 = 25.6%	1 = 90.6% 2 = 4.4% 3 = 5%	2 = 68.5% 3 = 24.4% 4 = 5.6% 5 = 1.5%	2 = 1.5% 3 = 98.5%	1 = 100%	5 = 28.2% 6 = 71.8%
24	Kendal District	1 = 51% 2 = 49%	1 = 89.8% 2 = 8.2% 3 = 2.0%	2 = 51% 3 = 38.8% 4 = 8.2% 5 = 2%	3 = 100%	1 = 100%	5 = 28.6% 6 = 71.4%
25	Batang District	1 = 75% 2 = 25%	1 = 88.2% 2 = 2.2% 3 = 8.5%	2 = 65.1% 3 = 25.9% 4 = 7.5% 5 = 1.4%	2 = 0.9% 3 = 99.1%	1 = 100%	5 = 12.7% 6 = 87.3%
26	Pekalongan District	1 = 76.8% 2 = 23.2%	1 = 80.4% 2 = 7.1% 3 = 12.5%	2 = 62.5% 3 = 25% 4 = 7.2% 5 = 5.4%	2 = 3.6% 3 = 96.4%	1 = 100%	5 = 16.1% 6 = 83.9%
27	Pemalang District	1 = 29.3% 2 = 70.7%	1 = 95.1% 2 = 2.4% 3 = 2.4%	2 = 29.3% 3 = 65.9% 4 = 2.4% 5 = 2.4%	3 = 100%	1 = 100%	5 = 68.3% 6 = 31.7%
28	Tegal District	1 = 50.9% 2 = 49.1%	1 = 79.2% 2 = 5.7% 3 = 15.1%	2 = 35.8% 3 = 43.4% 4 = 20.8%	2 = 1.9% 3 = 98.1%	1 = 100%	4 = 1.9% 5 = 60.4% 6 = 37.7%
29	Brebes District	1 = 38.6% 2 = 61.4%	1 = 84.1% 2 = 6.8% 3 = 9.1%	2 = 36.4% 3 = 47.7% 4 = 9.1% 5 = 6.8%	3 = 100%	1 = 100%	5 = 70.5% 6 = 29.5%
30	Semarang City	1 = 64% 2 = 36%	1 = 95.7% 2 = 1.4% 3 = 2.9%	2 = 61.4% 3 = 35.3% 4 = 1.9% 5 = 1.4%	3 = 100%	1 = 100%	5 = 100%
31	Salatiga City	1 = 61.4% 2 = 38.6%	1 = 89.2% 2 = 4.8% 3 = 6%	2 = 54.2% 3 = 38.6% 4 = 4.8% 5 = 2.4%	3 = 100%	1 = 100%	5 = 16.9% 6 = 83.1%
32	Magelang City	2 = 23%	1 = 78.3% 2 = 4.3% 3 = 17.4%	3 = 78.3% 4 = 4.3% 5 = 17.4%	3 = 100%	1 = 100%	5 = 69.6% 6 = 30.4%
33	Surakarta City	1 = 47.3% 2 = 52.7%	1 = 87% 2 = 4.9% 3 = 8.2%	2 = 41.3% 3 = 46.7% 4 = 8.7% 5 = 3.3%	2 = 1.1% 3 = 98.9%	1 = 100%	5 = 6% 6 = 94%
34	Tegal City	1 = 54.2% 2 = 48.5%	1 = 83.3% 3 = 16.7%	2 = 45.8% 3 = 37.5% 4 = 8.3% 5 = 8.3%	3 = 100%	1 = 100%	5 = 100%
35	Pekalongan City	1 = 13.3% 2 = 86.7%	1 = 83.3% 2 = 3.3% 3 = 13.3%	2 = 3.3% 3 = 83.3% 4 = 6.7% 5 = 6.7%	3 = 100%	1 = 100%	5 = 93.3% 6 = 6.7%

) was the description of hazardous waste score in Central Java Province:

3.4. Hazardous Waste Risk Level by City/District

Based on the risk calculations, the average risk of hazardous waste in Central Java Province was 0.501. Rembang District had the highest risk score for the hazardous waste type, with an average of 0.684, while Wonosobo District had the lowest risk value for the hazardous waste type at 0.409. The results of the risk analysis of hazardous waste types by district/city in Central Java Province are presented in the following

Table 8. Hazardous and Toxic Waste Risk Score by District/City in Central Java Province in 2021.

No	Districts/Cities	Average	At Least	Maximum	SD
1	Cilacap District	0.463	0.33	1.0	0.15
2	Banyumas District	0.536	0.33	0.833	0.112
3	Purbalingga District	0.449	0.33	1.0	0.144
4	Banjarnegara District	0.498	0.4	1.0	0.158
5	Kebumen District	0.549	0.33	1.0	0.142
6	Purworejo District	0.599	0.33	1.0	0.168
7	Magelang District	0.539	0.33	1.0	0.131
8	Temanggung District	0.432	0.33	1.0	0.136
9	Wonosobo District	0.409	0.33	0.833	0.145
10	Klaten District	0.508	0.4	0.8	0.134
11	Sukoharjo District	0.498	0.33	1.0	0.166
12	Wonogiri District	0.479	0.33	1.0	0.128
13	Karanganyar District	0.429	0.33	0.67	0.1
14	Sragen District	0.485	0.33	0.8	0.132
15	Boyolali District	0.465	0.33	1.0	0.148
16	Grobogan District	0.451	0.33	0.83	0.125
17	Blora District	0.512	0.33	0.83	0.146
18	Rembang District	0.684	0.33	1.0	0.169
19	Pati District	0.482	0.333	1.0	0.152
20	Kudus District	0.506	0.333	1.0	0.166
21	Jepara District	0.532	0.333	1.0	0.148
22	Demak District	0.492	0.333	1.0	0.135
23	Semarang District	0.422	0.333	1.0	0.122
24	Kendal District	0.458	0.333	0.833	0.124
25	Batang District	0.418	0.333	0.833	0.118
26	Pekalongan District	0.438	0.333	0.833	0.144
27	Pemalang District	0.526	0.333	0.833	0.114
28	Tegal District	0.532	0.333	0.8	0.126
29	Brebes District	0.544	0.333	1.0	0.165
30	Semarang City	0.486	0.4	1.0	0.121
31	Salatiga City	0.439	0.333	0.833	0.119
32	Magelang City	0.638	0.5	1.0	0.121
33	Surakarta City	0.46	0.333	1.0	0.13
34	Tegal City	0.558	0.4	1.0	0.186
35	Pekalongan City	0.627	0.333	1.0	0.119
	Total Average	0.501

below:

Most cities/districts in Central Java Province had an average percentage of hazardous waste type risk level in the low category (Figure 2). Rembang District had a large percentage of the medium risk level category for hazardous waste.

3.5. Geographical Distribution Patterns of Hazardous Waste

Figure 3 and Figure 4 depict the geographical distribution of the hazardous waste producing sector. It is clear that the geographical distribution of the hazardous waste-producing sector in Central Java Province (purple dot) tends to be evenly distributed and centered in the middle of the province, following the existence and geographical positions of large cities/districts.

Figure 4 shows that the composition of the hazardous waste-producing sector in Central Java Province, which shows an almost similar proportion between category 1 and category 2 hazardous waste categories.

Figure 5 demonstrates that that category 1 hazardous waste hotspots in Central Java Province overlapped with each other, especially the hazardous waste-producing sector points from health care facilities, industrial areas, and oil and gas and mining fields. Meanwhile, the category 2 hazardous waste hotspots overlapped with the hazardous waste-producing sector points from the electrification and industrial fields (Figure 6). This is supported by the modeling of the composition of hazardous waste category 1 (Figure 7) which shows health care, industry, and manufacture sites as the sectors that produced hazardous waste category one in Magelang district, Jepara district, Sukoharjo district, and Semarang City. In contrast, it was somewhat different for the modeling the composition of hazardous waste category 2 (Figure 8) which showed the electricity, oil and gas, and industry sector domination in various areas, including Jepara, Sukoharjo, Temanggung, Demak, Wonogiri, Salatiga, Pekalongan, Cilacap, and Semarang districts/cities.

3.6. Disaster Risk Index in Central Java Province

The Indonesian Disaster Risk Index (Index Risiko Bencana Indonesia, IRBI) is an index which describes the risk level of disasters within certain areas (province or district). Thus, the calculation of the disaster-prone index is obtained from the casualties (deaths and injuries) and damage (houses and facilities/infrastructure) as the impacts of a disaster and population density. In calculations using the IRBI, the index studied is the disaster risk. Disaster risk is an assessment of the likelihood of an estimated impact if the hazard becomes a disaster. Therefore, the calculation emphasizes the potential possibility and magnitude of the impact as measured by the exposure of each hazard and the combination of several existing hazards (multi-hazard). IRBI currently focuses on natural disasters, whilst the need to include industrial disaster in the future is already identified.

Central Java Province has five active volcanoes, namely Mount Slamet, Mount Dieng, Mount Sindoro, Mount Sumbing, and Mount Merapi. In addition, Central Java is also home to several active faults across the area, namely the Baribis Kendeng Fault, Ajibarang Fault, Ungaran Fault, Merapi-Merbabu Fault, Muria Fault, and Pati Thrust Fault. In the south of Central Java, there is also the Java Megathrust Zone with a Central Java Segment. This condition puts the districts/cities in Central Java Province in a moderate- to-high risk class, with all types of threats faced by this province. As many as 26% of districts/cities have a high IRBI category. The highest IRBI score is identified in Brebes District, while the lowest is found in Surakarta City. Based on the 2021 IRBI, Central Java Province has a risk index of 125.73 (moderate). The Disaster Risk Index score in Central Java Province by district/city is presented in

Table 9. Disaster Risk Index Score and Category by District/City in Central Java Province in 2021.

No	District/City	Disaster Risk Index Score	Disaster Risk Level Category
1	Brebes District	189.94	High
2	Pati District	171.10	High
3	Banyumas District	164.25	High
4	Purworejo District	163.63	High
5	Batang District	161.93	High
6	Pekalongan District	160.19	High
7	Tegal District	158.93	High
8	Purbalingga District	148.12	High
9	Pemalang District	146.38	High
10	Pekalongan City	138.13	Medium
11	Jepara District	135.11	Medium
12	Sragen District	133.75	Medium
13	Rembang District	131.73	Medium
14	Grobogan District	131.66	Medium
15	Boyolali District	130.32	Medium
16	Banjarnegara District	127.36	Medium
17	Wonogiri District	124.77	Medium
18	Blora District	123.19	Medium
19	Temanggung District	121.33	Medium
20	Kudus District	119.71	Medium
21	Semarang District	118.89	Medium
22	Tegal City	116.80	Medium
23	Kebumen District	114.67	Medium
24	Cilacap District	112.75	Medium
25	Semarang City	108.63	Medium
26	Karanganyar	108.03	Medium
27	Magelang City	108.00	Medium
28	Demak District	105.21	Medium
29	Wonosobo District	102.83	Medium
30	Kendal District	100.40	Medium
31	Klaten District	99.24	Medium
32	Sukoharjo District	93.20	Medium
33	Salatiga City	91.20	Medium
34	Magelang District	71.16	Medium
35	Surakarta City	67.96	Medium
	Provincial Average	125.73	Medium

.

Description of disaster risk level categories at the provincial level is provided below:

• Total Score of <13: Class 1 → Low-Risk Class
• Total Score of 13–144: Class 2 → Medium-Risk Class
• Total Score of >144: Class 3 → High-Risk Class

According to the IRBI, the high-risk threats in Central Java Province are forest and land fires, droughts, and floods. Forest and land fire disasters dominate the cities or districts in Central Java Province.

Table 10. Risk Index Score by Disaster Type by City/District in Central Java Province in 2021.

No	District/City	Risk Level Score by Disaster Type
		Flood	Earthquake	Tsunami	Volcanic Eruption	Forest and Land Fire	Landslide	Extreme Tide	Drought	Extreme Weather
1	Brebes District	23.92	14.35	-	5.32	23.92	15.95	23.92	-	9.04
2	Pati District	34	20.40	-	-	34	11.33	24.00	22.67	19.27
3	Banyumas District	16.59	9.95	10.99	7.37	16.59	11.06	-	16.59	6.27
4	Purworejo District	17.08	10.25	11.32	-	17.08	11.39	17.08	11.39	6.45
5	Batang District	31.39	9.42	-	-	31.39	20.92	20.92	20.92	11.86
6	Pekalongan District	24.95	15.48	-	-	25.81	17.20	16.06	17.20	14.62
7	Tegal District	16.94	10.89	-	12.10	18.15	12.10	12.10	18.15	6.85
8	Purbalingga District		16.59	-	12.29	27.65	27.65	-	27.65	10.45
9	Pemalang District	17.01	10.56	-	7.82	17.60	11.73	11.73	17.60	6.65
10	Pekalongan City	26.42	8.49	-	-	26.42	8.81	17.61	17.61	10.69
11	Jepara District	22.77	6.83	-	-	22.77	7.59	24.00	15.18	12.90
12	Sragen District	28.06	17.42	-	-	29.03	9.68	-	19.35	10.97
13	Rembang District	16.94	10.89	-	-	18.15	6.05	24.00	12.10	10.28
14	Grobogan District	17.33	10.40	-	-	17.33	5.78	-	17.33	9.82
15	Boyolali District	9.49	8.54	-	6.33	14.23	9.49	-	9.49	5.38
16	Banjarnegara District	-	10.76	-	-	17.89	17.89	-	17.89	10.14
17	Wonogiri District	-	11.30	2.30	-	18.83	12.55	11.72	12.55	7.11
18	Blora District	22.77	13.66	-	-	22.77	7.59	-	15.18	12.90
19	Temanggung District	-	13.66	-	15.18	22.77	15.18	-	15.18	8.60
20	Kudus District	25.81	15.48	-	-	12.62	8.60	-	17.20	14.62
21	Semarang District	15.63	9.38	-	-	15.63	5.21	-	10.42	5.90
22	Tegal City	16.94	21.60	-	-	-	11.20	14.40	22.40	13.60
23	Kebumen District	13.38	8.03	8.92	-	13.38	4.46	8.92	13.38	5.05
24	Cilacap District	14.39	8.64	9.60	-	14.39	9.60	9.60	14.39	5.44
25	Semarang City	17.54	10.89	-	-	18.15	6.05	17.54	12.10	10.28
26	Karanganyar	4.80	9.25	-	-	15.42	10.28	-	10.28	5.82
27	Magelang City	-	21.60	-	5.60	33.60	11.20	-	22.40	13.60
28	Demak District	20.37	12.22	-	-	20.37	6.79	19.02	13.58	11.54
29	Wonosobo District	-	8.93	-	6.62	14.89	9.93	-	9.93	5.62
30	Kendal District	22.33	13.40	-	-	22.33	7.44	14.89	-	8.44
31	Klaten District	-	7.60	-	5.63	12.66	4.22	-	8.44	4.78
32	Sukoharjo District	-	21.60	-	-	23.20	11.60	-	23.20	13.60
33	Salatiga City	-	21.60	-	-	22.40	11.20	-	22.40	13.60
34	Magelang District	-	7.25	-	8.05	12.08	8.05	-	8.05	4.56
35	Surakarta City	-	10.76	-	-	-	11.16	-	11.16	6.78
	Total score	476.85	438.07	43.13	92.31	673.5	376.93	287.51	523.36	333.48

The description of disaster risk level categories at the provincial level is provided below: Total Score of <13: Class 1 → Low Risk Class Category. Total Score of 13–144: Class 2 → Medium Risk Class Category. Total Score of >144: Class 3 → High Risk Class Category.

describes the level of natural disaster risk in Central Java in more detail.

4. Discussion

4.1. Central Java and Hazardous Waste Generation

The results of this study suggested that Central Java has a variety of kinds of hazardous waste (HW) generated in the area, comprising of 4042 types of HW that are generated in large amounts, totaling 2,886,974,024 tons during 2021. This amount is similar to the total HW produced in the whole of Nigeria [4]. Our results suggest that the sector that generates the largest amount of hazardous waste is the healthcare sector. This is likely linked to the large population of Central Java Province which makes it necessary for this province to provide a large number of health care facilities. This condition is reinforced by a map showing the generation of hazardous waste from health care facilities that spreads throughout Central Java Province. This situation is different from the situation in Spain, where the manufacturing sector accounts for 80% of hazardous waste generation, with the service sector as the second hazardous waste-contributing sector [7]. In China, hazardous waste generation accounts for 11.62 million tons in 2005 [18]; hence, the hazardous waste generated in Central Java is much higher when compared to China. The different waste generation amounts in different sectors are likely to be influenced by the activities of each type of business in an area. In addition, the range of hazardous waste generation produced from each type of hazardous waste in each city is very wide. This is because there is no uniform guideline on how to calculate the risk analysis of hazardous waste. Indeed, the large amount of hazardous waste generated create a high risk to the large population of Central Java Province, as well as creating a huge challenge in the environmental management. Furthermore, any failure on hazardous waste management will bring a high potential risk to the human health within the province.

4.2. Types and Characteristics of Hazardous Waste in Central Java

Most hazardous waste produced in Central Java is toxic waste, followed by flammable, corrosive, reactive, and infectious waste. In Nigeria, toxic waste is also the most produced hazardous waste, generated from carbon dioxide gas flaring, electronic waste, household waste, and oil spillage [19]. The government of Central Java needs to be prepared for potential industrial disasters derived from hazardous waste. Indeed, the diverse types of hazardous waste produced in the province make it mandatory for this province to have a better hazardous waste management, including the basic approach from EPA’s Cradle-to-Grave Hazardous Waste Management Program, as well as better hazardous waste generation identification, transportation, recycling, treatment, storage, disposal, and regulations [20]. Emergency responses in case of failures in hazardous waste management need to be prepared, including the emergency response plan, emergency responders, human resources capacities, infrastructure and response facilities, coordination, and communication system for better emergency responses under potential hazardous waste emergencies. The government of Central Java needs to implement the Penta helix approach in collaboration with the industries and communities to deal with industrial disasters. The Penta helix approach involves academia, industry, communities, the media, and government in accident prevention, risk communication, industrial disaster response, and recovery [20].

4.3. Hazardous Waste Risk Level in Central Java

Most cities/districts in Central Java Province have a low risk for hazardous waste (92.52%), with a small percentage of cities/districts in the medium category (7.48%). No city/district is in the high-risk category for hazardous waste. This is likely due to the fact that the amount of hazardous waste generated in each type of business/activity is so large that when it is categorized using the existing formula, the result still shows the low-risk category. The regulation of the Government of the Republic of Indonesia is different from the EPA. The Government Regulations of the Republic of Indonesia stated that the generation of hazardous waste with a weight of more than 30 tons (300,000/month) is considered to reflect a high-risk category. Meanwhile, when referring to the EPA, the high-risk generation of hazardous waste is achieved when the waste generated is more than 1000 kg/month. Thus, it is necessary to recalculate and regroup for the determination of category of hazardous waste generation.

From the perspective of the city/district, Rembang District (40%) has a medium average risk for hazardous waste while the area with the lowest category risk is Karanganyar District (100%). Although the risk level of each type of hazardous waste is still mostly low, the Provincial government must be aware of the existence of multi-hazards, because this province is prone to natural disasters, such as floods, forest and land fires, and droughts. If hazardous waste is not managed properly and a flood occurs, the waste will spread to various regions in Central Java, affecting a broad area and a lot of people. Mismanagement of hazardous waste in some developing countries have shown to cause environmental contamination and major threats to public health [21].

4.4. Geographical Distribution Patterns of Hazardous in Central Java

Based on our GIS mapping, it is clearly shown that the distribution of hazardous waste in Central Java is quite disperse throughout the area. Meanwhile the distribution of industrial plants as a source of hazardous waste in Changhua County in Taiwan is clustered in some areas [22]. The potential risks of environmental damage and contamination should be a high concern since the majority of the areas in this province generate hazardous waste. Indeed, environmental monitoring of potential contamination to environmental media including air, water and land should be strictly conducted to prevent environmental damage and potential leachate of hazardous waste to the environment. The health and safety of the workers should also be a concern as they are vulnerable to hazards, as shown in the case of Dhaka [23,24] where operators did not consider the occupational health and safety of their employees, leading to potentially dire consequences. Furthermore, since most of the hazardous waste is derived from healthcare facilities, it is suggested that proper infectious hazardous waste management should be implemented to prevent uncontrolled final disposal sites, such as those in Palestine [25]. Since Central Java also has a high risk of natural disaster, future research is needed to evaluate the impact of natural hazards triggering technological disasters, or Natech, similar to the study conducted in Cilegon area [26,27].

5. Conclusions and Suggestions

Central Java Province consist of 35 cities/districts with a total of 1233 activities/businesses generating 4042 types of hazardous waste. In 2021, the amount of hazardous waste generated in Central Java Province was 2,886,974.024 tons, with the healthcare sector as the largest contributor to hazardous waste generation in the province. Therefore, hazardous waste management in the health care sector must receive strong attention from the local government, by making a guideline for hazardous waste management in health facilities available and by providing training for personnel who manages hazardous waste in healthcare facilities.

Most cities/districts in Central Java Province have a low risk level for hazardous waste (92.52%), with a small percentage (7.48%) in the medium category and none categorized as high risk. Although the risk level of each type of hazardous waste is still mostly low, the provincial government must be aware of multi-hazard potentials due to the existing natural disaster potential shown by a high Disaster Risk Index for this province, with forest and land fires, droughts, and floods as the potential disasters of concern.

The characteristics of hazardous waste generated in this province are mostly toxic and infectious. The geographical distribution of the hazardous waste-producing sector in Central Java shows that the geographical distribution pattern of the hazardous waste-producing sector tends to be evenly distributed and centered in the middle area due to the existence and geographical position of large cities/districts. The composition of the hazardous waste-producing sector appears to be almost similar between category 1 and category 2. Hazardous waste category 1 is generally dominated by the health care facilities, workshops, industrial areas, and oil and gas and mines in Magelang (District), Jepara, Sukoharjo, and Semarang (city), while hazardous waste category 2 is dominated by electricity, oil, and gas and industry sectors in Jepara, Sukoharjo, Temanggung, Demak, Wonogiri, Salatiga, Pekalongan, Cilacap and Semarang (district).

The healthcare sector needs to receive the most attention in hazardous waste management and preparation for relevant emergencies. Based on the characterization, most hazardous waste is toxic and infectious in nature; thus, it is crucial to prepare emergency equipment and reduce exposure to these types of waste by developing a tailored regional emergency plan and exposure reduction measures. The alternative actions that could be taken to reduce the risk from hazardous waste disaster in Central Java can be seen in the

Table 11. Risk Identifications and Recommended Actions to Reduce the Risk.

No	Risk Identification	Actions to Reduce the Risk
1.	Hazardous waste is dominated by toxic and infectious waste.	Prepare emergency equipment and reduce exposure by developing a regional emergency plan and exposure reduction measures.
2.	Healthcare facilities produced the highest amount of hazardous waste.	Making a guideline for hazardous waste management in healthcare, provide trained personnel to manage hazardous waste.
3.	No hazardous emergency program currently exists.	Provide a hazardous emergency plan.
5.	The sources of hazardous waste are quite dispersed in all areas.	Providing a clustered area for industrial sectors to reduce the exposure of hazardous materials towards the community.

below.